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1. The Neutral minimum and Neutral maximum parameters should be as close as possible to maximize the accuracy of your speed control but they should still be far enough from eachother so that you can reliably reach a scaled value of 0 when you put your input in the neutral position e g release your finger from the joystick Some joysticks can settle at different positions depending on where you release the from so you should experiment with releasing your joystick from different positions and see what Raw Values you get you can see them using Current channel value label or in the Status tab Then set Neutral minimum and Neutral maximum so that their range includes all of the values you saw and has a reasonable margin This guarantees that you will not waste any power driving your motor when your stick is in the neutral position 3 Ifyou want to restrict the scaled value of the channel to always be negative or always be positive you can set the Minimum equal Neutral Minimum or you can set Maximum equal to Neutral Maximum This could be useful for one directional control of a motor but typical applications will not need this 5 1 1 Configuring a Limit or Kill Switch Limit switches and kill switches help protect your motor controller from performing unwanted actions For example analog limit switches could be configured to prevent your actuator from moving out of its valid range An RC kill switch could be configured to conveniently i
2. Windows Vista or Windows 7 device manager showing a Simple Motor Controller In Linux the COM port name will be something like dev ttyacmo In Mac OS X 10 7 or later the COM port name will be something like dev cu usbmodemfal21 You can use a terminal program or computer software to send commands to this virtual serial port over USB Most common programming languages have libraries for sending serial data e g Visual C has a SerialPort class which makes it easy to write a custom computer program to control the Simple Motor Controller See Section 6 7 for code examples The baud rate settings do not matter when communicating through the virtual COM port 6 Using the Serial Interface Page 60 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation TTL Serial The Simple Motor Controller s serial receive line RX can receive bytes from a TTL serial source such as a microcontroller which allows for integration into embedded systems The RX line expects a logic level 0 to 2 5 V or TTL non inverted serial signal The voltage on the RX pin should not go below 0 V and should not exceed 5 V The Simple Motor Controller provides logic level 0 to 3 3 V serial output on its serial transmit line TX The bytes sent by the motor controller on TX are typically responses to commands that request information but they can also be data received by the TXIN pin and passed on If you aren t inte
3. 1 or 9 Max Acceleration Reverse 0 3200 0 no limit aspre per update period 2 or 10 Max Deceleration Reverse 0 3200 0 no limit Aspoed per update period 3 or 11 Brake Duration Reverse 0 16384 4ms 9 Note The Brake Duration units used by this command are 4 ms which differs from 1 ms units used by the Brake Duration variables returned by the Get Variable command Note that the Hard Motor Limit settings place restrictions on the limit values you can set with this command see Section 5 2 for more information on the hard motor limits The hard limits configured through the Simple Motor Control Center are considered minimal safety requirements and the temporary limits cannot be changed in a way that makes the controller less safe than this This means that the Maximum Speed Acceleration and Deceleration temporary limits cannot be increased beyond their hard limit counterparts and the Brake Duration limits cannot be decreased below their hard limit counterparts If you try to set a temporary limit in a way prohibited by the corresponding hard limit the temporary limit value is set to the hard limit and the response code byte indicates that the value could not be set as requested If the arguments to this command are valid the controller responds to this command with an ASCH digit E Description 0 No problems setting the limit sil Unable to set forward limit to the specified value bec
4. setMotorLimit DECELERATION 20 clear the safe start violation and let the motor run exitSafeStart main loop of the program this executes over and over while the program runs void loop static int speed 3200 full speed forward setMotorSpeed speed speed speed switch motor direction clear clear the LCD and move cursor to start of first row print ts signed variables must be cast to ints print _long int getVariable TARGET SPEED lcd_goto_xy 0 1 move LCD cursor to start of second row if is digital input high errPin if an error is stopping the motor print the error status variable in hex and try to re enable the motor print Err print _hex getVariable ERROR_STATUS once all other errors have been fixed this lets the motor run again exitSafeStart else print input voltage in Volts to the LCD print VIN unsigned int vin getVariable INPUT _VOLTAGE print truncated whole number of Volts print_unsigned_long vin 1000 print _character print rounded tenths of a Volt print_unsigned_long vin 1000 50 100 delay _ms 1000 program execution starts here int main setup while 1 loop 6 7 3 Cross platform C Example The example C code below works on Windows Linux and Mac OS X 10 7 or later It demonstrates how to get the error status from the controll
5. If your hardware came with an installation CD lt 6 or floppy disk insert it now What do you want the wizard to do Install the software automatically Recommended Install from a list or specific location Advanced Click Next to continue 8 Windows XP will warn you again that the driver has not been tested by Microsoft and recommend that you stop the installation Click Continue Anyway rere Winar Pete mat mide the mumi eat ls he sohase e 7 The bef m pe riding be the hetnae F bat S AA Pogerme Hag aeg Post Puas USB AVA Pogana Pogara Pot han rot paned ardoen Loge wrrg ety t coroaty th Winton F l e ta Sus iaa DILET mae emision od I sed temene may mga 9 When you have finished the Found New Hardware Wizard click Finish After that another wizard will pop up You will see a total of two wizards when plugging in a Simple Motor Controller Follow steps 6 9 for each wizard 3 Getting Started Page 13 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Found New Hardware Wizard Completing the Found New Hardware Wizard The wizard has finished installing the software for a Pololu Simple High Power Motor Controller 18 15 Click Finish to close the wizard 9 If you use Windows XP and experience problems installing or using the serial port drivers the cause of your problems might be a bug in older versions of Microsoft s usb
6. some variable IDs define ERROR STATUS 0 define LIMIT STATUS 3 define TARGET SPEED 20 define INPUT VOLTAGE 23 define TEMPERATURE 24 some motor limit IDs define FORWARD ACCELERATION 5 define REVERSE ACCELERATION 9 define DECELERATION 2 read a serial byte returns 1 if nothing received after the timeout expires int readByte char c if smcSerial readBytes amp c 1 0 return 1 return byte c required to allow motors to move must be called when controller restarts and after any error void exitSafeStart smcSerial write 0x83 speed should be a number from 3200 to 3200 void setMotorSpeed int speed if speed lt 0 smcSerial write 0x86 motor reverse command speed speed make speed positive else smcSerial write 0x85 motor forward command smcSerial write speed amp Oxl1F smcSerial write speed gt gt 5 unsigned char setMotorLimit unsigned char JlimitID unsigned int limitValue smcSerial write 0xA2 smcSerial write limitID smcSerial write limitValue amp Ox7F smcSerial write limitValue gt gt 7 return readByte returns the specified variable as an unsigned integer if the requested variable is signed the value returned by this function should be typecast as an int unsigned int getVariable unsigned char variableID 6 Using the Serial Interface Page 96 of 108 Pololu Simple
7. 2001 2015 Pololu Corporation 6 2 Binary Commands When configured in Binary serial mode the Simple Motor Controller offers several serial command protocols similar to that of other Pololu products Communication is achieved by sending serial command packets consisting of a single command byte followed by any data bytes that command requires not all commands require data bytes some command packets simply consist of a single command byte Command bytes always have their most significant bits set while data bytes almost always have their most significant bits cleared 0x80 128 lt command byte lt 0xFF 255 0x00 0 lt data byte lt 0x7F 127 This means that each data byte can only transmit seven bits of information The only exception to this is the Mini SSC command where the command byte is OxFF or 255 and the data bytes can have any value from 0x00 to OxFE 0 to 254 Note If you are using the TTL serial interface and the motor controller is in Auto Detect Baud Rate mode you must send the baud rate indication byte 0xAA or 170 on the RX line before sending any commands The 0OxAA baud rate indication byte can be the first byte of a Pololu protocol command or it can be transmitted as a single byte Communication via the controller s virtual COM port is unaffected by baud rate settings and does not require the transmission of an initial baud rate indication byte 3 This guide displays byte values in the format
8. 26 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation USB mini B GND connector RC power selectable RC signal input channels Potentiometer Potentiometer Analog voltage input channels potentiometer outputs RC Interface TTL Serial Interface Microcontroller Analog Interface Joystick Potentiometer Limit Switch Brushed DC Motor Battery 4 1 Connecting Power and a Motor Warning Take proper safety precautions when using high power electronics Make sure you know what you are doing when using high voltages or currents During normal operation this product can get hot enough to burn you Take care when handling this product or other components connected to it 4 Connecting Your Motor Controller Page 27 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation The first step in using your Simple Motor Controller is connecting power and a motor With those connections in place you can immediately start testing with the Simple Motor Control Center The following section explains the power system in detail USB mini B Simple Motor Controller 18v7 power and motor connections USB mini B Simple High Power Motor Controller 18v15 or 24v12 power and motor connections 4 Connecting Your Motor Controller Page 28 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation USB mini B GN
9. 7 57 Bash Script Example ss 905 4 eu ay Be Pi ee we EE wR eee ee ES 105 6 7 6 CRC Computation in C oaaae 106 7 Writing PC Software to Control the Simple Motor Controller oaoa a 108 Page 2 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 1 Overview The Pololu Simple Motor Controllers are versatile general purpose motor controllers for brushed DC motors A wide operating range of up to 5 5 40V and the ability to deliver up to several hundred Watts in a small form factor make these controllers suitable for many motor control applications With a variety of supported interfaces USB for direct connection to a computer TTL serial for use with embedded systems RC hobby servo pulses for use as an RC controlled electronic speed control ESC and analog voltages for use with a potentiometer or analog joystick and a wide array of configurable settings these motor controllers make it easy to add basic control of brushed DC motors to a variety of projects Although this motor controller has many more features than competing products a free configuration Simple Motor Controllers utility for Windows 8 7 Vista Windows XP and Linux simplifies initial setup of the device and allows for in system testing and monitoring of the controller via USB For 24 V applications we recommend the 24v12 or 24v23 versions We strongly recommend against using the 18v7 18v15 or 18v25 with 24 V batteri
10. ANI Unlimited Raw Value AN1 Raw Value ANI Scaled Value AN2 Unlimited Raw Value AN2 Raw Value AN2 Scaled Value Type unsigned 16 bit unsigned 16 bit signed 16 bit unsigned 16 bit unsigned 16 bit signed 16 bit Diagnostic Variables 2001 2015 Pololu Corporation Description Units The 12 bit ADC reading of analog channel 1 This value is OxFFFF 0 0 V 65535 if the controller detects the input is disconnected 4095 3 3 V The 12 bit ADC reading of analog channel 1 This value is OXFFFF 65535 if the controller detects the input is disconnected or if the 0 0 V signal is outside of the Error Max Error Min channel calibration 4095 3 3 V settings The scaled version of the AN1 raw value based on analog channel 1 calibration settings This value is 0 if the raw value is OxFFFF ee else it ranges from 3200 to 3200 nia 0 0 V See AN1 Unlimited Raw Value 4095 3 3 V 0 0 V See AN1 Raw Value 4095 3 3 V See AN1 Scaled Value internal units The following variables can be used to monitor various internal conditions of the Simple Motor Controller such as the input voltage the board temperature the and the motor speed 6 Using the Serial Interface Page 88 of 108 Pololu Simple Motor Controller User s Guide ID 20 21 22 23 24 26 27 28 29 Name Target Speed Speed Brake Amount Input Voltage Temperature RC Period Baud Rate R
11. Pololu Corporation Command Byte Data Byte1 Data Byte 2 Compact Protocol OxE0 224 Pololu Protocol OxAA 170 device number 0x60 96 Description This command sets the motor target speed to zero and makes the controller susceptible to a safe start violation error if Safe Start is enabled Put another way this command will stop the motor configured deceleration limits will be respected and not allow the motor to start again until the Safe Start conditions required by the Input Mode are satisfied This command has no serial response 6 3 ASCII Commands When configured in ASCII serial mode the Simple Motor Controller offers a simple serial interface based on ASCII characters This mode makes it easy to interact with the Simple Motor Controller through a terminal program such as HyperTerminal and it can provide a more intuitive interface for users who would rather deal with character strings than bits and bytes There are some limitations when using ASCII mode however e The commands are longer than their Binary mode Compact Protocol counterparts so they will take longer to send when using a TTL serial connection e Automatic baud detection is not available you must configure the Simple Motor Controller to the appropriate fixed baud rate ahead of time if you are communicating using TTL serial e CRC error detection is not available e The ASCII mode serial responses might be harder to parse with some programming la
12. Power ES a i Motor Controller r Rx 4 0 90 outB Engage Your Brain VIN www pololu com GNO Simple High Power Motor Controller 18v15 or 24vi2 bottom view with dimensions 1 3 18v25 and 24v23 Included Hardware Simple High Power Motor eee a Simple High Power Motor Controller 18v25 or 24v23 e on a ae id F Controller 18v25 or 24v23 with m TERE E NOT with included hardware instanced included The highest power controller versions 18v25 and 24v23 are sold without the power capacitor and connectors installed no fully assembled version is available They ship with a 40x1 straight 0 1 male header strip https www pololu com product 965 a 5mm pitch 4 pin terminal block https www pololu com product 2440 and a power capacitor as shown in the left picture above For applications under 15 A these pieces can be soldered to the board as shown in the middle picture above higher current applications should use thick wires soldered directly to the board or higher current connectors https www pololu com product 925 such as those shown in the right picture above 1 Overview Page 8 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Pololu High Power Motor Controller umc03b 0 2416 2 10 Simple High Power Motor Controller 18v25 or 24v23 bottom view with dimensions 1 4 Supported Operating Systems The Simple Motor Controller USB drivers and configuration softw
13. Simple High Power Motor Simple Motor Controller Controller 18v15 or 24v12 The fully assembled 18v7 18v15 and 24v12 Simple Motor Controller versions ship with terminal blocks soldered into the large VIN OUTA OUTB and GND pads and a power capacitor pre installed as shown in the pictures above These terminal blocks make it easy to connect and disconnect power supplies but they are only rated for 15 A 4 Connecting Your Motor Controller Page 31 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Simple High Power Motor Controller Simple High Power Motor Controller 18v15 or 24v12 partial kit with 18v25 or 24v23 with included included hardware hardware Simple High Power Motor Controller Simple High Power Motor Controller 18v25 or 24v23 with custom power 18v15 or 24v12 partial kit with and motor connectors NOT included custom power and motor connectors NOT included All other versions ship with terminal blocks and a power capacitor included but not installed which provides flexibility in making connections These versions offer two options for connecting to the high power signals VIN OUTA OUTB GND large holes on 0 2 centers which are compatible with the included terminal blocks https www pololu com product 2440 and pairs of 0 1 spaced holes which are compatible with the included 0 1 male header strip https www pololu com product 965 and can be used with perfboar
14. Simple Motor Controller s serial mode to be either Binary or ASCII depending on which command set you want to use See Section 6 7 for example code that uses the virtual COM port 7 Writing PC Software to Control the Simple Motor Controller Page 108 of 108
15. Using the Serial Interface The Simple Motor Controller has two serial interfaces that allow you to send commands and receive responses from the controller The commands and responses are represented as a series of bytes http simple wikipedia org wiki Byte Serial commands let you set the speed of the motor when the Input Mode is Serial USB In any Input Mode serial commands let you request information about the motor controller s state and monitor the RC and Analog channel inputs The serial commands can come from a TTL serial source such as a microcontroller transmitted to the motor controller s RX pin or they can come via USB transmitted to the controller s virtual COM port The Simple Motor Controller treats the two command sources independently and can simultaneously process commands from both sources The Simple Motor Controller can also be controlled using its native USB interface see Section 7 COM Port The Simple Motor Controller installs as two devices one of which is a virtual serial COM command port see Section 3 1 for driver installation instructions You can identify the COM port number by looking in your computer s Device Manager File Action View Help e968 amp Network adapters 5h Pololu USB Devices pou Ba Pololu Simple High Power Motor Controller 18v15 Ports COM amp LPT P Communications Port COM1 Pololu Simple High Power Motor Controller 18v15 Command Port COM5 a Processors
16. baud rate detection can be used but it is not recommended because of inaccuracy in the SoftwareSerial library Simple Example This example assumes the following connections exist between the Arduino and the Simple Motor Controller e Arduino digital pin 4 to Simple Motor Controller RX e Arduino GND to Simple Motor Controller GND There is nothing special about Arduino pin 4 you can use any free digital pins other than 0 and 1 the Arduino s hardware serial lines if you change the pin definition at the top of the sample program accordingly See Section 4 2 for more information on connecting a serial device to the Simple Motor Controller This program demonstrates how to initiate serial communication with the Simple Motor Controller and how to send commands to set the motor speed For information about the serial commands used by this sample code refer to Section 6 2 1 Note that the Simple Motor Controller must be powered when this Arduino sketch starts running include lt SoftwareSerial h gt define rxPin 3 pin 3 connects to smcSerial TX not used in this example define txPin 4 pin 4 connects to smcSerial RX SoftwareSerial smcSerial SoftwareSerial rxPin txPin 6 Using the Serial Interface Page 94 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation required to allow motors to move must be called when controller restarts and after any error void exitSafeStart smcSe
17. can conveniently immobilize from a distance using an RC transmitter and receiver The Forward and Reverse Limit Switch options allow you to set up limits that prevent your actuator from moving out of its allowed range See Section 4 4 for information about connecting limit switches You will probably want to avoid setting a motor deceleration limit if you are using a limit switch because the deceleration limit will prevent the motor from stopping immediately when the switch is triggered the motor will gradually decelerate from its current speed to zero which might be bad for your system depending on how it is set up Any channel configured as a limit or kill switch is considered a required channel This means that the motor will stop if that channel becomes disconnected the Required channel invalid error will occur Learn button The Learn button launches the Channel Setup Wizard which lets you quickly calibrate your input channel or limit switch Before using this wizard you should select your desired Alternate Use and if you are configuring an analog channel then you should first enable the pull up resistor and check Ignore Pot Disconnect in the Advanced Settings tab if necessary Enable pull up resistor analog channels only When checked the Enable pull up resistor option enables a pull up resistor on the selected analog input line The value of the resistor is approximately 40 kQ and it pulls the line up to 3 3 V Scaling P
18. connect the ERR pin to one of the microcontroller s digital inputs Connecting one of the microcontroller s digital outputs to the RST pin allows the microcontroller to selectively reset the Simple Motor Controller 4 Connecting Your Motor Controller Page 36 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Microcontroller with TTL UART Simple Motor Controller GND Optional The ERR Pin in Detail One function of the ERR pin is to communicate that an error is preventing the motor from moving When such an error occurs the red error LED turns on and the ERR pin outputs 3 3 V When there are no errors stopping the motor the ERR pin is pulled low and the red error LED is off Because the ERR pin never drives low it is safe to connect the ERR pins of multiple Simple Motor Controllers to the same microcontroller input If any one of those controllers experiences an error the microcontroller error input goes high and the error LEDs of all connected Simple Motor Controllers light up By default the ERR pin is also configured to serve as an input that stops the motor when externally driven above 2 3 V This means that the error lines of multiple Simple Motor Controllers can be connected together and all motor controllers will shut down their motors when any one motor controller experiences an error This technique of connecting error lines can be used even when RC signals or analog voltages are used to
19. contact us https www pololu com contact directly or post on our forum http forum pololu com Tell us what we did well what we could improve what you would like to see in the future or anything else you would like to say 2 Contacting Pololu Page 10 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 3 Getting Started 3 1 Installing Windows Drivers and Software If you are using Windows XP you will need to have Service Pack 3 http www microsoft com downloads details aspx FamilyId 68C48DA D BC34 40BE 8D85 6BB4F56F5110 installed before installing the drivers for the Simple Motor Controller See below for details Before you connect a Simple Motor Controller to a computer running Microsoft Windows you should install the drivers 1 Download the Simple Motor Controller Windows Drivers and Software https www pololu com file download smc windows 121204 zip file_id 0J408 SMB zip 2 Open the ZIP archive and run setup exe The installer will guide you through the steps required to install the Simple Motor Control Center the Simple Motor Controller command line utility SmcCmd and the Simple Motor Controller drivers on your computer If the installer fails you may have to extract all the files to a temporary directory right click setup exe and select Run as administrator 3 During the installation Windows will ask you if you want to install the drivers Click In
20. diagram shows the internal circuitry of the TX and TXIN pins Simple Motor Controller Schematic diagram of the Simple Motor Controller TXIN and TX pins See Section 6 6 for more information on connecting multiple controllers on the same serial line 4 3 Connecting an RC Receiver Simple Motor Controller can be directly connected to an RC receiver allowing for wireless manual motor control The RC inputs can serve several functions from directly controlling the motors RC input mode to 4 Connecting Your Motor Controller Page 38 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation sending signals to an autonomous robot Serial USB mode to providing an RC kill switch any input mode The Simple Motor Controller can derive motor speed from a single RC input channel or it can mix the signals on both RC channels to generate the motor speed which makes intuitive throttlet steering control of a differential drive robot possible using a pair of Simple Motor Controllers A BEC jumper lets the Simple Motor Controller optionally power your RC receiver at 3 3 or 5 V eliminating the need for a second battery a ee Ld p GND RC power selectable RC signal input channels eeenreer ee a gt 1i fra _ Simple High Power Motor Controller 18v25 or 24v23 RC connections 4 Connecting Your Motor Controller Page 39 of 108 Pololu Simple Motor Controller User s Guide 2
21. error see Section 3 4 5 4 Upgrading Firmware The Simple Motor Controller has field upgradeable firmware that can be easily updated when Pololu releases bug fixes or new features Firmware Versions e Version 1 00 This is the original version e Version 1 01 This version fixes a bug that made the ASCII Get Variable serial command malfunction for negative numbers e Version 1 02 This version fixes a bug that caused the controller to detect the wrong baud rate if the baud rate detection byte was sent during the first two milliseconds after a reset e Version 1 03 released on 2010 11 18 This version fixes a bug that caused the yellow LED to flicker sometimes e Version 1 04 released on 2012 08 09 This version fixes some bugs with error handling The effect of the Exit Safe Start serial command now lasts for 200 ms instead of ending immediately and the ERR line high error now works in RC and analog mode 5 Configuring Your Motor Controller Page 58 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Upgrade Instructions You can determine the version of your controller s firmware by running the Pololu Simple Motor Control Center software connecting to the controller and selecting Device Information from the Device menu If you do not have the latest firmware you can upgrade the firmware by following these steps Linux users The Simple Motor Controller s firmware cannot be upgr
22. errors that have occurred since this variable was last cleared Reading this variable clears all of the bits See Section 3 4 for serial error descriptions e Bit 0 reserved f Bit 1 Frame Serial 2 Errors Bit 2 Noise Occurred e Bit 3 RX Overrun e Bit 4 Format e Bit 5 CRC e Bits 6 16 reserved The set bits of this variable indicate things that are currently limiting the motor controller e Bit 0 Motor is not allowed to run due to an error or safe start violation e Bit 1 Temperature is active reducing target speed iim e Bit 2 Max speed limit is actively reducing target speed target speed gt max speed Status e Bit 3 Starting speed limit is actively reducing target speed to zero target speed lt starting speed e Bit 4 Motor speed is not equal to target speed because of acceleration deceleration or brake duration limits 6 Using the Serial Interface Page 85 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation e Bit 5 RCI is configured as a limit kill switch and the switch is active scaled value gt 1600 e Bit 6 RC2 limit kill switch is active scaled value gt 1600 e Bit 7 ANI limit kill switch is active scaled value gt 1600 e Bit 8 AN2 limit kill switch is active scaled value gt 1600 e Bit 9 USB kill switch is active e Bits 10 15 reserved Flags indicating the source of the last board reset This variable does not change while the contro
23. for an example int smcGetVariable int fd unsigned char variableId unsigned char command 0xAl variableId if write fd amp command sizeof command 1 perror error writing return SERIAL ERROR unsigned char response 2 if read fd response 2 2 perror error reading return SERIAL ERROR return response 0 256 response 1 Returns the target speed 3200 to 3200 Returns SERIAL ERROR if there is an error int smcGetTargetSpeed int fd int val smcGetVariable fd 20 return val SERIAL ERROR SERIAL ERROR signed short val Returns a number where each bit represents a different error and the bit is 1 if the error is currently active See the user s guide for definitions of the different error bits Returns SERIAL ERROR if there is an error int smcGetErrorStatus int fd return smcGetVariable fd 0 Sends the Exit Safe Start command which is required to drive the motor Returns 0 if successful SERIAL ERROR if there was an error sending int smcExitSafeStart int fd const unsigned char command 0x83 6 Using the Serial Interface Page 103 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation if write fd amp command 1 1 perror error writing return SERIAL ERROR return 0 Sets the SMC s target speed 3200 to 3200 Returns 0 if successful SERIAL ERROR if there was an err
24. hex decimal where hex is the hexadecimal http simple wikipedia org wiki Hexadecimal base 16 representation of the byte s value and decimal is the decimal representation of the byte s value The hexadecimal representation starts with the prefix Ox e g 0x10 Keep in mind that a byte is simply a number between 0x00 0 and OxFF 255 For serial protocols the important thing about a byte is its value not the notation e g hex decimal or binary you use in your source code to write the byte The following three sub protocols are available in binary serial mode Compact Protocol This is the simpler and more compact of the two protocols it is the protocol you should use if your Simple Motor Controller is the only device connected to your serial line The compact protocol command packet is simply command byte MSB set data byte 1 data byte 2 data byte n 1XXXXXXX OXXXXXXX OXXXXXXX OXXXXXXX For example if we want to set the motor speed to 3200 full speed forward we could send the following byte sequence Hex notation 0x85 0x00 0x64 Decimal notation 133 0 100 6 Using the Serial Interface Page 64 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation The byte 0x85 is the Set Motor Forward command and the last two bytes contain the speed Pololu Protocol This protocol is compatible with the serial protocol used by our other serial motor an
25. int limitValue command 0 command 1 command 2 limitValue amp Ox7F command 3 limitValue gt gt 7 sendBlocking command 4 OxA2 limitID char response 1 receiveBlocking amp response 1 500 return response returns the specified variable as an unsigned integer if the requested variable is signed the value returned by this function should be typecast as an int unsigned int getVariable unsigned char variableID command 0 OxAl1 command 1 variableID sendBlocking command 2 unsigned int response if receiveBlocking char amp response 2 500 return 0 if we don t get a response in 500 ms return 0 return response initialization code called once when the program starts running void setup setBaudRate 115200 briefly reset SMC when Arduino starts up optional set_digital_output resetPin LOW delay ms 1 wait 1 ms set_digital input resetPin HIGH IMPEDANCE let SMC run again 6 Using the Serial Interface Page 101 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation must wait at least 1 ms after reset before transmitting delay _ms 5 this lets us read the state of the SMC ERR pin optional set_digital_input errPin HIGH IMPEDANCE command 0 OxAA sendBlocking command 1 send baud indicator byte setMotorLimit FORWARD ACCELERATION 4 setMotorLimit REVERSE ACCELERATION 10
26. only channel 1 affects motor speed If mixing mode is set to right or left channel 1 is considered the throttle input and channel 2 is considered the steering input Left mixing mode obtains motor speed by summing the throttle and steering channels CH1 CH2 while right mixing mode obtains motor speed by taking the difference of the throttle and steering channels CH1 CH2 To see why this makes sense 4 Connecting Your Motor Controller Page 44 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation consider a differential drive robot a robot with a motor on each side with a left motor driven by a Simple Motor Controller in left mixing mode and a right motor driven by a Simple Motor Controller in right mixing mode When throttle is full forward CH1 max and steering is neutral CH2 0 left and right mixed motors are both driven forward at full speed and the robot goes forward When throttle is neutral CH1 0 and steering is full right CH2 max the left mixing results in motor forward at full speed while right mixing results in motor reverse at full speed so the robot turns right As demonstrated above using both analog channels in mixing mode makes it possible to combine two joystick controlled Simple Motor Controllers to achieve single stick mixed control of a differential drive robot The connection diagram for such a setup would be very similar to the RC mixing diagram shown in Se
27. outputs Simple High Power Motor Controller 18v25 or 24v23 analog connections Analog Connections Overview The analog connection block consists of two channels Each channel has a signal pin and a and pin for powering the analog voltage source These potentiometer power pins are special in that they allow the Simple Motor Controller to detect if an analog channel has become disconnected so we recommend using these pins rather than alternate power supplies or other pins on the board 9 If you use an analog voltage source that is not powered from the Simple Motor Controller s potentiometer power and pins you will need to check the Ignore Pot Disconnect checkbox under the Advanced Settings tab of the Simple Motor Control Center see Section 5 3 We recommend using a potentiometer in the 1 kQ to 10 kQ range Higher resistance potentiometers will not work well with the potentiometer disconnection detection feature If you need to use a higher resistance potentiometer you can disable potentiometer disconnection detection from the Simple Motor Control Center 4 Connecting Your Motor Controller Page 43 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Note The analog channel inputs are not 5V tolerant so you must not connect voltages over 3 3 V to these pins If your control source outputs voltages higher than 3 3 V you can use a voltage divider to ensure the voltage is always at an acce
28. the opposite With the Invert motor direction option enabled Forward means the average voltage on OUTA is less than the average voltage on OUTB 5 Configuring Your Motor Controller Page 54 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation The PWM frequency setting specifies the frequency of the rapidly switching PWM signal used to control the speed of the motor Several PWM Frequency options are available between 1 12 and 21 77 kHz The default PWM frequency is 21 77 kHz This is an ultrasonic frequency it is too high for humans to hear so you won t hear the high pitched whine from the motor that other motor controllers can cause Using a lower PWM frequency will reduce switching losses and slightly increase the power output to the motor because the duty cycle the percentage of the time that the H bridge is powering the motor can be closer to 100 Note that a speed of 3200 is called 100 but it does not correspond to a duty cycle of 100 The correspondence between maximum duty cycle and PWM frequency is shown in the table below PWM Frequency Duty cycle when speed is 100 21 77 kHz 96 8 11 07 kHz 98 4 7 42 kHz 98 9 5 58 kHz 99 2 4 47 kHz 99 3 3 20 kHz 99 5 2 04 kHz 99 7 1 12 kHz 99 8 Speed zero brake amount is a number between 0 and 32 that specifies how strongly to brake the motor when the Current Speed is set to 0 This corresponds to the percentage of time that the low side MOS
29. to serial driver usbser sys Versions of this driver prior to version 5 1 2600 2930 will not work with the Simple Motor Controller You can check what version of this driver you have by looking in the Details tab of the Properties window for usbser sys in C Windows System32 drivers To get the fixed version of the driver you will need to install Service Pack 3 http www microsoft com downloads details aspx FamilyId 68C48DA D BC34 40BE 8D85 6BB4F56F5110 If you do not want Service Pack 3 you can try installing Hotfix KB918365 instead but some users have had problems with the hotfix that were resolved by upgrading to Service Pack 3 The Simple Motor Control Center and SmcCmd will work even if the serial port drivers are not installed properly After installing the drivers if you go to your computer s Device Manager and expand the Ports COM amp LPT list you should see the Command Port for the Simple Motor Controller In parentheses you will see the name of the port e g COMS5 or COM6 If you expand the Pololu USB Devices list you should see another entry for the Simple Motor Controller 3 Getting Started Page 14 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation File Action View Help e9 mEl H amp ao Network adapters S N Pololu USB Devices E Ports COM amp LPT _ J Communications Port COM1 l B LE Pololu Simple High Power Motor Control
30. unsigned The positive pulse width of the signal on RC channel 1 This value is 5 Value 16 bit OxFFFF 65535 if no valid signal is detected or if the signal is outside 0 25 us of the Error Max Error Min channel calibration settings RC1 i The scaled version of the RCI raw value based on RC channel signed ln ts internal 6 Scaled 16 bit calibration settings This value is 0 if the raw value is OxFFFF else it nit Value ranges from 3200 to 3200 eee RC2 Unlimited unsigned ro 8 Rank 16 bit See RC1 Unlimited Raw Value 0 25 us Value RC2 Raw unsigned 9 Value 16 bit See RC1 Raw Value 0 25 us Ree igned internal 10 Scaled Sine See RC1 Scaled Value s 16 bit units Value Analog Channel Inputs The raw and scaled voltages measured on the analog channel inputs are always available through serial variable requests which allows programs using the serial interface to factor the channel inputs into their motor control algorithms If the controller detects a disconnected potentiometer this requires potentiometer disconnect detection to be enabled under the Advanced Settings tab the raw channel value is reported as OxFFFF 65535 and the scaled channel value is reported as 0 The Simple Motor Controller is always reading the analog input channels even when the Input Mode is not Analog 6 Using the Serial Interface Page 87 of 108 Pololu Simple Motor Controller User s Guide ID 12 13 14 16 17 18 Name
31. unsigned char CRC7_POLY 0x91 unsigned char getCRC unsigned char message unsigned char length unsigned char i j cre 0 for i 0 i lt length i cre message i for j 0 j lt 8 j if cre amp 1 crc CRC7_POLY cre gt gt 1 return crc int main create a message array that has one extra byte to hold the CRC unsigned char message 3 0x83 0x01 0x00 message 2 getCRC message 2 send this message to the Simple Motor Controller Advanced Example The following example program shows a more efficient way to compute a CRC in the C language The increased efficiency is achieved by pre computing the CRCs of all 256 possible bytes and storing them in a lookup table which can be in RAM flash or EEPROM These table values are then XORed together based on the bytes of the message to get the final CRC In the example main routine this is applied to generate the CRC byte in the message 0x83 0x01 that was used in Section 6 5 include lt stdio h gt const unsigned char CRC7_POLY 0x91 unsigned char CRCTable 256 unsigned char getCRCForByte unsigned char val unsigned char j for j 0 j lt 8 j if val amp 1 val CRC7_ POLY val gt gt 1 return val void buildCRCTable tye a fill an array with CRC values of all 256 possible bytes 6 Using the Serial Interface Page 106 of 108 Pololu Simple Motor Co
32. via USB bin bash Sets the speed of a Simple Motor Controller via its virtual serial port Usage smc set speed sh DEVICE SPEED Linux example bash smc set speed sh dev ttyACMO 3200 Mac OS X example bash smc set speed sh dev cu usbmodemfal21 3200 Windows example bash smc set speed sh USBSEROO00 3200 Windows example bash smc set speed sh COM6 3200 DEVICE is the name of the virtual COM port device SPEED is a number between 3200 and 3200 DEVICE 1 SPEED 2 byte printf x printf Sx 1 byte 0x83 exit safe start if SPEED lt 0 J then byte 0x86 motor reverse SPEED SPEED else byte 0x85 motor forward fi byte SPEED amp 0x1F byte SPEED gt gt 5 amp 0x7F gt SDEVICE This script can also be run on Windows but since Windows does not have bash installed by default it is easier to use SmcCmd 6 Using the Serial Interface Page 105 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 6 7 6 CRC Computation in C Simple Example The following example program shows how to compute a CRC byte in the C language The outer loop processes each byte and the inner loop processes each bit of those bytes In the example main routine this is applied to generate the CRC byte in the message 0x83 0x01 that was used in Section 6 5 The getcrc function will work without modification in both Arduino and Orangutan programs const
33. weight of the board without header pins terminal blocks or through hole power capacitor Warning Take proper safety precautions when using high power electronics Make sure you know what you are doing when using high voltages or currents During normal operation this product can get hot enough to burn you Take care when handling this product or other components connected to it 1 1 18v7 Included Hardware Simple Motor Controller 18v7 partial kit with included hardware Simple Motor Controller 18v7 fully assembled 1 Overview Page 6 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation The lowest power controller version 18v7 is available with the power capacitor and connectors included but not soldered in as shown in the left picture above or with the power capacitor and connectors pre installed as shown in the right picture above The power capacitor has a significant effect on performance the included capacitor is the minimum size recommended and bigger ones can be added if there is space A bigger capacitor might be required if the power supply is poor or far more than about a foot from the controller 0 086 Pololu 2010 Pololu Simple Motor Controller 1 10 m Engage Your Brain www pololu com umc03c 0 2600 Simple Motor Controller 18v7 bottom view with dimensions 1 2 18v15 and 24v12 Included Hardware Simple High Power Mo
34. you are done running the Quick Input Setup you should be able to successfully control your motor as long as you have made all the necessary electrical connections as described in Section 4 The rest of this section documents all of the Input Settings in detail If you are able to control the motor the way you want to after running the Quick Input Setup Wizard then you probably don t need to read this section 3 The serial settings in the Input Settings tab are not documented here If you want to use the serial interface please see Section 6 5 Configuring Your Motor Controller Page 47 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation F Pololu Simple Motor Control Center File Edit View Device Help Connected to 1815 39FF 6806 3054 3036 1128 0743 Status rent Settings Motor Settings Advanced Settings Sera Protocol Quek input Setup Seral Mode input Mode Moing Mode Bray Senal USB None ASCH Analog FC Analog Channel 1 input Settings beam Scaling degree 1 Linear L invert input drection Neutral Neutral Erormin Minimum minimum maimum Ma mum Eror max o ip 40 ems is 2000 i oss ie 4095 e Current channel value 2024 Units Ois 0V 409518 3 3 V xa Buang 2 32 Motor topped Prees Resume to sat Input Settings tab in the Pololu Simple Motor Control Center Input Mode The Input Mode specifies what kind of input the co
35. 0 16384 4 ms 9 Note The Brake Duration units used by this command are 4 ms which differs from 1 ms units used by the Brake Duration variables returned by the Get Variable command The first limit value byte limit byte 1 can be computed by taking the full limit value modulo or mod 128 which is the same as dividing the value by 128 discarding the quotient and keeping only the remainder We can get the same result using binary math by bitwise ANDing the limit with 0x7F 127 In C and many other programming languages these operations can be carried out with the following expressions limit byte 1 limit 128 or equivalently limit_byte_1 limit amp 0x7F The second limit value byte limit byte 2 can be computed by dividing the full limit value by 128 discarding the remainder and keeping only the quotient i e turn the division result into a whole number by dropping everything after the decimal point We can get the same result using binary math by bit shifting the limit right seven places In C and many other programming languanges these operations can be carried out with the following expressions limit_byte_2 limit 128 or equivalently limit byte 2 limit gt gt 7 Note that the Hard Motor Limit settings place restrictions on the limit values you can set with this command see Section 5 2 for more information on the hard motor limits The hard limits configured through the Simple Motor Control Cente
36. 0 V 40 V 30 V 40 V Recommended max voltage 24V 24 V 34 V 24 V 34 V Max continuous current w o heat sink 7A 15A 12A 25A 23A It is very important that you select a power source that does not exceed the absolute maximum voltage rating for your Simple Motor Controller Ripple voltage on the supply line can raise the maximum voltage to more than the average or intended voltage so we recommend you to select a voltage that leaves at least a 6 V margin for noise It is also important to note that batteries can be much higher than their nominal voltage when fully charged so 4 Connecting Your Motor Controller Page 29 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation we do not recommend using the 18v7 18v15 or 18v25 versions with 24 V batteries unless appropriate measures are taken to limit the peak voltage For 24 V applications we recommend the 24v12 or 24v23 versions We strongly recommend against using the 18v7 18v15 or 18v25 with 24 V batteries which can significantly exceed 24 V when fully charged and are dangerously close to the maximum voltage limits of these lower voltage controllers Using a 24 V battery with an 18vX Simple Motor Controller makes the device much more susceptible to damage from power supply noise or LC voltage spikes Finally make sure you select a power source that is capable of delivering the current your motor will require e g alkaline cells are typically poor choices fo
37. 001 2015 Pololu Corporation RC Connections Overview The RC connection block consists of two channels oriented as columns and a battery elimination circuit BEC column for supplying power to the RC receiver Each channel has a ground pin outlined in black in the above diagrams a power pin outlined in red in the above diagrams and a signal pin outlined in yellow in the above diagrams The RC signal pins can read standard hobby servo RC pulses with peaks anywhere from 2 to 5 V The included shorting block https www pololu com product 968 can be used to supply the power pin row with either 3 3 V or 5 V which in turn can be used to power an RC receiver Note If you want to connect servos directly to your RC receiver you must power it separately as the Simple Motor Controller s regulators cannot supply enough current to power a servo If your RC receiver is powered separately you must leave the BEC jumper off to avoid shorting the motor controller s regulated voltage to your RC receiver s power source Your receiver and Simple Motor controller must always have a common ground even if you power the RC receiver separately The channel pins have a 0 1 spacing which means that a female female servo extension cable https www pololu com product 780 can be used to connect an RC receiver directly to the board Simple Wiring Example Connecting to an RC Receiver RC receiver Simple Motor Controller GND BEC jumper select
38. 170 device number 0x12 18 brake amount 6 Using the Serial Interface Page 70 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Description This command causes the motor to immediately brake by the specified amount configured deceleration limits are ignored The Brake Amount byte can have a value from 0 to 32 with 0 resulting in maximum coasting the motor leads are floating almost 100 of the time and 32 resulting in full braking the motor leads are shorted together 100 of the time Requesting a brake amount greater than 32 results in a Serial Format Error This command has no serial response Example To set the motor outputs to 50 braking a Brake Amount of 16 we would transmit the following compact protocol bytes We Send Command Byte Data Byte 1 Compact Protocol 0x92 146 0x10 16 Get Variable any input mode Command Format Command Byte Data Byte1 Data Byte 2 Data Byte 3 Compact Protocol 0xA1 161 variable ID Pololu Protocol OxAA 170 device number 0x21 33 variable ID Response Format Response Byte 1 Response Byte 2 variable low byte variable high byte Description This command lets you read a 16 bit variable from the Simple Motor Controller See Section 6 4 for a list of all of available variables The value of the requested variable is transmitted as two bytes with the low byte sent first You can reconstruct the variable value from the
39. 232 device directly to the Simple Motor Controller can permanently damage it 6 1 Serial Settings The behavior of the Simple Motor Controller s serial interface is determined by a number of settings almost all of which can be configured under the Input Settings tab of the Simple Motor Control Center Serial Protocol Serial Mode CRC Mode Binary Disabled 5 ASCII Commands only Device Number 13 s TTL Serial Auto detect baud rate Delay TTL serial responses Fixed baud rate 9600 The serial settings in the Input Settings tab of the Pololu Simple Motor Control Center Serial Mode The Serial Mode determines which protocols the Simple Motor Controller will accept e Binary In this mode the controller expects command packets comprised of a series of bytes that conform to the Compact Pololu or Mini SSC protocol formats see Section 6 2 for more information on these protocols The Binary protocol commands are more compact than their ASCII protocol counterparts so they can be transmitted faster and they let you send commands addressed to a particular device number so this mode should be used when multiple devices daisy chained together on the same serial line Note that some of the other serial settings documented below are only available in this mode e ASCII In this mode the controller expects command packets comprised of ASCII characters which makes the commands potentially more friendly to beg
40. 5 though the Simple Motor Control center will not let you set the controller s Device Number to a value greater than 127 If the Device Number byte matches the motor controller s device number or if the Device Number byte is 254 the motor controller will respond to the command all controllers respond to Mini SSC commands addressed to Device Number 254 3 The Simple Motor Controller identifies the Pololu Compact and Mini SSC protocols on the fly when configured in Binary serial mode you do not need to use a configuration parameter to identify which of these three protocols you are using and you can freely mix commands in the three protocols Trying the Binary Serial Interface If you are having trouble using the Binary protocols it can help to first use a program like the Pololu Serial Transmitter utility for Windows https www pololu com docs 0J23 to send bytes to the Simple Motor Controller s virtual COM port This program makes it easy send packets of arbitrary bytes which can help you identify if your problems are with your control software or with the bytes you are trying to send The Serial Transmitter Utility can even automatically append the appropriate CRC7 byte to the end of the transmitted command packet 6 Using the Serial Interface Page 66 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Pololu Serial Transmitter v1 3 Connected COM Port COM4 Baud Rate 112500 bps _ appe
41. AND the inputs that control the speed of the motor are not near their neutral positions This helps prevent the situation where there might be an error stopping your motor such as a disconnected battery and the motor starts running at a high speed when you fix the error To clear the Safe start violation error move all the inputs that control the speed of the motor to their neutral positions the sum of the absolute values of their scaled values must be less than 8 e Required channel invalid This error occurs whenever any required RC or Analog channel is invalid This error helps ensure that your motor will stop if you accidentally disconnect your joystick potentiometer 3 Getting Started Page 20 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation or RC receiver A channel is invalid if it is disconnected or has a value that is out of range A channel is required if it controls the speed of the motor or it is configured as a limit switch or kill switch By default there are no required channels because the input mode is serial and no limit or kill switches have been configured You can check the Input Settings tab to see which channels are required Channels that are required and invalid are highlighted in red in the Input Channels box of the Status tab so you can quickly see which channel is causing this error e Command timeout This error occurs if you are controlling your motor using a microcontrolle
42. B with free configuration program Windows 8 7 Vista Windows XP and Linux compatible Note A USB A to mini B cable https vww pololu com product 130 not included is required to connect this controller to a computer Additional Features e Adjustable maximum acceleration and deceleration to limit electrical and mechanical stress on the system e Adjustable starting speed maximum speed and amount of braking when speed is zero Optional safety controls to avoid unexpectedly powering the motor Input calibration learning and adjustable scaling degree for analog and RC signals Under voltage shutoff with hysteresis for use with batteries vulnerable to over discharging e g LiPo cells e Adjustable over temperature threshold and response e Adjustable PWM frequency from 1 kHz to 22 kHz maximum frequency is ultrasonic eliminating switching induced audible motor shaft vibration Error LED linked to a digital ERR output and connecting the error outputs of multiple controllers together optionally causes all connected controllers to shut down when any one of them experiences an error Field upgradeable firmware USB Serial features e Controllable from a computer with native USB via serial commands sent to the device s virtual serial COM port or via TTL serial through the device s RX TX pins Example code in C Visual Basic NET and Visual C is available in the Pololu USB Software Developme
43. D BEC connector RC power selectable SH pst Simple High Power Motor Controller 18v25 or 24v23 power and motor connections Power Considerations The Pololu Simple Motor Controllers can be powered either from USB using a USB A to mini B cable https www pololu com product 130 or from a power supply such as a battery pack connected to the large VIN and GND pads When the VIN supply is not present the controller can use USB power to perform all of its functions except for driving the motor The controller automatically selects VIN as the power source when it is present even when USB is connected It is OK to have both USB and VIN power simultaneously connected Power for the motor must be supplied to the controller through the large VIN and GND pads The smaller VIN and GND pads on the left side of the board in the diagrams above are not suitable for high currents and should not be used to power the motor controller These smaller power pins provide a convenient way to pass the input voltage on to other parts in your system but they should not be used to power anything that will draw more than 500 mA All Simple Motor Controller versions can operate from VIN supplies as low as 5 5 V but the maximum continuous output current will be lower for voltages under 7 V The maximum power ratings for the Simple Motor Controllers are shown below Simple Motor Controller 18v7 18v15 24v12 18v25 24v23 Absolute max voltage 30 V 3
44. FETs will be turned on and braking the motor The default is 32 which means full brake This means that whenever the Current Speed gets set to zero because of an error or any other reason the motor will brake as fast as possible and it will be relatively hard to turn the motor by hand while it is stopped If you would prefer that your motor have a more gradual stop or be easier to turn while it is stopped you can set Speed zero brake amount to 0 which is almost full coast Another way to have gradual stops is to set a deceleration limit which will cause the Current Speed to slowly drop to zero 5 3 Advanced Settings The Advanced Settings tab lets you fine tune the details of how your Simple Motor Controller behaves 5 Configuring Your Motor Controller Page 55 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Ba Pololu Simple Motor Control Center File Edit View Device Help Connected to 18v15 39FF 6806 3054 3036 1128 0743 EA Low VIN startup V High VIN shutoff V VIN multiplier offset E Never sleep ignore USB suspend Command Timeout s 10 00 Advanced Settings tab in the Pololu Simple Motor Control Center VIN Detection These options specify how to measure the voltage on the VIN line The Low VIN options specify what constitutes a Low VIN error A Low VIN error occurs when the voltage on the VIN line drops below the Low VIN shutoff voltage and stays be
45. For more information on these limits see the section that documents the Motor Settings tab Input Channels The Input Channels box in the Status tab shows the current status of the RC or Analog input channels of the device The Raw Value is the raw unscaled value of the input channel For RC channels the Raw Value is the width of pulses received on the input line RC1 or RC2 It is typically between 1000 us and 2000 us and it is stored internally as an integer in units of quarter microseconds 6000 corresponds to 1500 us For Analog channels the Raw Value is the average voltage measured on the input line Al or A2 It is always between 0 mV and 3300 mV and it is stored internally as a 12 bit integer 0 corresponds to 0 mV while 4095 corresponds to 3300 mV The Scaled Value is a number between 3200 and 3200 that is determined entirely by the Raw Value and the scaling parameters in the Input Settings tab If the scaling parameters are set up correctly then the Scaled Value should be 0 when the input is in its neutral position if it has a neutral position and they should be 100 3200 internally when the input is moved to either extreme The Status column summarizes the state of each channel Here are the different things you might see in the Status column e Valid There is an RC or Analog input connected to this channel and it is working e Invalid disconnected This message is shown for Analog channels when the control
46. For sample C code that computes the CRC byte of a command packet see Section 6 7 6 3 The CRC implemented on the Simple Motor Controller is the same as the one on the Maestro https www pololu com product 1352 servo controller and jrk https www pololu com product 1392 and qik https www pololu com product 1110 motor controllers but it differs from that on the TReX https www pololu com product 777 _ motor controller Instead of being done MSB first the computation is performed LSB first to match the order in which the bits are transmitted over the serial line In standard binary notation the number 0x91 is written as 10010001 However the bits are transmitted in this order 1 0 0 0 1 0 0 1 so we will write it as 10001001 to carry out the computation below The CRC 7 algorithm is as follows 1 Express your 8 bit CRC 7 polynomial and message in binary LSB first The polynomial 0x91 is written as 10001001 2 Add 7 zeros to the end of your message 3 Write your CRC 7 polynomial underneath the message so that the LSB of your polynomial is directly below the LSB of your message 4 Ifthe LSB of your CRC 7 is aligned under a 1 XOR the CRC 7 with the message to get a new message if the LSB of your CRC 7 is aligned under a 0 do nothing 5 Shift your CRC 7 right one bit If all 8 bits of your CRC 7 polynomial still line up underneath message bits go back to step 4 6 What s left of your message is now your CRC 7 resu
47. Motor Controller User s Guide smcSerial write 0xAl smcSerial write variableID return readByte 256 readByte void setup Serial begin 115200 for debugging optional smcSerial begin 19200 briefly reset SMC when Arduino starts up optional pinMode resetPin OUTPUT digitalWrite resetPin LOW reset SMC delay 1 wait 1 ms pinMode resetPin INPUT let SMC run again must wait at least 1 ms after reset before transmitting delay 5 this lets us read the state of the SMC ERR pin optional pinMode errPin INPUT smcSerial write 0xAA send baud indicator byte setMotorLimit FORWARD ACCELERATION 4 setMotorLimit REVERSE ACCELERATION 10 setMotorLimit DECELERATION 20 clear the safe start violation and let the motor run exitSafeStart void loop setMotorSpeed 3200 full speed forward signed variables must be cast to ints Serial printin int getVariable TARGET SPEED delay 1000 setMotorSpeed 3200 full speed reverse Serial printin int getVariable TARGET SPEED delay 1000 z write input voltage in millivolts to the serial monitor Serial print VIN Serial print getVariable INPUT_VOLTAGE Serial printlin mV 2001 2015 Pololu Corporation if an error is stopping the motor write the error status variable and try to re enable the motor if digitalRead errPin HIGH S
48. Out USB mini B GND connector RC power selectable ret ry CI RC signal input channels Bl ee Ct Fated i 0 Be TX TTL serial output 5 RX TTL serial input tus a VIN power output a As a a fn Analog none ee aneennt AOON Potentiometer Potentiometer Pot 9 Q lt Analog input channel 1 Analog ch 2 O lt za potentiometer output pot output gt ow RC Interface RC Receiver USB Interface PC TTL Serial Interface Microcontroller Analog Interface Joystick Potentiometer Limit Switch Brushed DC Motor 4 Connecting Your Motor Controller Page 25 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Simple High Power Motor Controller 18v15 and 24v12 Pin Out USB mini B GND connector RC power selectable RC signal input channels 11 1 ne ERR error O lt gt sug p JSBLED TLE nn RST board reset S Error kpn J GND TX TTL serial output RX TTL serial input elf OUTA Potentiometer Potentiometer Potentiometer Potentiometer Analog input channel 1 Analog input channel 2 potentiometer output potentiometer output Battery RC Interface RC Receiver USB Interface PC J TTL Serial Interface Microcontroller Analog Interface Joystick Potentiometer Limit Switch Brushed DC Motora Simple High Power Motor Controller 18v25 and 24v23 Pin Out 4 Connecting Your Motor Controller Page
49. Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Pololu Simple Motor Controller User s Guide Cp w a e w meet AES A A e View document on multiple pages https www pololu com docs 0J44 View this document as a printable PDF simple_motor_controllers pdf https www pololu com docs pdf 0J44 simple_motor_controllers pdf https www pololu com docs 0J44 all Page 1 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation T Overview a s E o a Pe eee eek Fe eS Eee a So AS OA Pea bE EO ee 3 Leds T8v7 Inchided Hard ware s a esas goaiaten ag 2 446d pe ae SS we Reg we alae Sale ad 6 1 2 18v15 and 24v12 Included Hardware 2 2 2 a 7 1 3 18v25 and 24v23 Included Hardware a 8 1 4 Supported Operating Systems oaa ee 9 2 Contacting Polos prsne masan gas Yds oh pp ied ae Bid Pie ne ee Fee ase Bak ee BE Ee 10 3 Getting Started a c soci ek ae eae eS ke ee a eee 2 ae Soe eee Rea Ee Ae 11 3 1 Installing Windows Drivers and Software 2 0 ee 11 3 2 Installing Linux Drivers and Software oaoa a 16 3 3 Understanding the Control Center Status Tab 2 2 2 ee 16 SA ETTOL Ser E eeta ea dace ds Ree Bide eral A tee vow Oy Ee ae ee ie ae 20 329 LED Feedback z n ai ots Kae Giw Ge aac Bre gas Bs a dete BGS coal at oR 22 4 Connecting Your Motor Controller aoaaa ee 25 4 1 Connecting Power anda Motor 2 2 20 0 ee 27 4 2 Conne
50. aded from a Linux computer This is due to bugs in recent versions of mono which we were able to reproduce on mono version Debian 2 10 8 1 Subuntu2 If you need to upgrade your firmware please use a computer running Windows 1 Save the settings stored on your controller using the Save settings file option in the File menu All of your settings will be reset to their default values during the firmware upgrade 2 Download the latest version of the firmware here Firmware version 1 04 for the Simple Motor Controllers https www pololu com file download smc_v1 04 fmi file_id 0J569 266k fmi This single file will work with all the different Simple Motor Controllers 3 Connect your controller to a Windows computer using a USB cable Do not attempt to upgrade the firmware on a Linux computer 4 Run the Pololu Simple Motor Control Center application and connect to the controller 5 In the Device menu select Upgrade firmware You will see a message asking you if you are sure you want to proceed click OK The Simple Motor Controller will now disconnect itself from your computer and reappear as a new device with a name like Pololu Simple High Power Motor Controller 18v15 Bootloader Windows 8 Windows 7 and Vista the driver for the bootloader will automatically be installed Windows XP follow steps 6 8 from Section 3 1 to get the driver working 6 Once the bootloader s drivers are properly inst
51. all variables as 16 bit 2 byte values transmitted least significant byte first though not all variables use all 16 bits 6 Using the Serial Interface Page 83 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Status Flag Registers Status flag registers are unsigned 16 bit values whose bits convey general information about the controller s status such as any errors have occurred the errors are currently stopping the motor and sources of controller output limitations 6 Using the Serial Interface Page 84 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation ID Name Description The set bits of this variable indicate the errors that are currently stopping the motor The motor can only be driven when this register has a value of 0 See Section 3 4 for error descriptions e Bit 0 Safe Start Violation e Bit 1 Required Channel Invalid e Bit 2 Serial Error e Bit 3 Command Timeout Error e Bit 4 Limit Kill Switch a Bit 5 Low VIN e Bit 6 High VIN e Bit 7 Over Temperature e Bit 8 Motor Driver Error e Bit 9 ERR Line High e Bits 10 15 reserved The set bits of this register indicate the errors that have occurred since this register was 1 rae d last cleared This status register has the same bit assignments as the Error Status register documented above Reading this variable clears all of the bits The set bits of this variable indicate the serial
52. alled the green LED should be blinking in a double heart beat pattern and there should be an entry for the bootloader in the Pololu USB Devices list of your computer s Device Manager 7 Go to the window titled Firmware Upgrade that the Pololu Simple Motor Control Center opened Click the Browse button and select the firmware file you downloaded 8 Ifit is not already selected select the device you want to upgrade from the Device dropdown box 9 Click the Program button You will see a message warning you that your device s firmware is about to be erased and asking you if you are sure you want to proceed click Yes 10 It will take a few seconds to erase the Simple Motor Controller s existing firmware and load the new firmware 11 Once the upgrade is complete the Firmware Upgrade window will close the Simple Motor Controller will disconnect from your computer once again and it will reappear as it was before If there is only one Simple Motor Controller plugged into your computer the Pololu Simple Motor Control Center will connect to it Check the firmware version number and make sure that it now indicates the latest version of the firmware If you run into problems during a firmware upgrade please contact us https www pololu com contact for assistance 5 Configuring Your Motor Controller Page 59 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 6
53. arameters The rest of channel specific settings are all scaling parameters which means they specify how the Scaled Value of the input channel is calculated from its Raw Value They also specify the normal range of the input channel All of these parameters except Scaling degree can be easily set using the Learn button The Raw Value of a channel is measured directly from the input pin For RC channels the Raw Value is the width of received pulses in units of 1 4 us typical RC receivers will generate signals between 4000 1000 us and 8000 2000 us For Analog channels the Raw Value is a 12 bit measurement of the voltage on the input line 0 is 0 V and 4095 is 3 3 V You can see the raw value of the selected channel by looking at the Current channel value label or by looking at the Status tab If the Raw Value is less than Error min or greater than Error max then the channel is considered invalid and the Scaled Value is not computed Otherwise the Scaled Value of a channel is calculated from the Raw Value using the scaling parameters Specifically e Raw values between Error min and Minimum map to a Scaled Value of 3200 or 3200 if Invert input direction is checked e Raw values between Minimum and Neutral minimum map to a Scaled Value between 3200 or 3200 if Invert input direction is checked and 0 e Raw values between Neutral minimum and Neutral maximum map to a Scaled Value of 0 e Raw values between Neutral m
54. are work under Microsoft Windows XP Windows Vista Windows 7 Windows 8 and Linux On ARM based Linux machines such as the Raspberry Pi the graphical configuration program the Simple Motor Control Center does not work This is caused by problems with Mono s implementations of WinForms on those systems We do not provide any software for Mac OS X but the controller s USB virtual COM port is compatible with Mac OS X 10 7 Lion and later As a result the Simple Motor Controller can be controlled from a Mac but a Windows or Linux computer is required if you need to change any of the configuration parameters 9 Mac OS X compatibility we have confirmed that the Simple Motor Controller works on Mac OS X 10 7 and we can assist with advanced technical issues but most of our tech support staff does not use Macs so basic support for Mac OS X is limited 1 Overview Page 9 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 2 Contacting Pololu You can check the Pololu Simple Motor Controller pages https www pololu com category 94 pololu simple motor controllers for additional information The Resources tab on each product page contains links to this users guide as well as other valuable resources such as drivers and the Simple Motor Control Center software We would be delighted to hear from you about any of your projects and about your experience with the Simple Motor Controller You can
55. ature maximum If the temperature rises above the Over temperature maximum an over temperature error will occur and the motor will stop In this mode the motor will keep on running as the board heats up but it might run slower due to the temperature based speed limiting RC Pulse Detection These parameters adjust how lenient or strict the RC signal measurement is on the RCI and RC2 lines If you use strict settings your controller will shut down faster when the RC signal is lost and be less likely to act on corrupted data If you use lenient settings your controller will be more likely to keep operating when the RC signal quality is poor Consecutive good pulses is the number of consecutive good pulses that must be received before the controller starts heeding good pulses and updating the channel value The default value of 2 means that after 2 good pulses in a row are received the third one will be used to update the channel value A value of 0 means that every good pulse results in an update of the channel value Increasing this number makes your settings more strict while decreasing it makes them more lenient Minimum pulse period and Maximum pulse period specify limits on the amount of time allowed between pulses If a pulse is received too soon after a previous pulse it is considered bad If the pulses on the line stop then the RC input channel s signal is considered invalid after an amount of time equal to the Maximum pulse period has e
56. ause of Hard Motor Limit settings 2 Unable to set reverse limit to the specified value because of Hard Motor Limit settings 3 Unable to set forward and reverse limits to the specified value because of Hard Motor Limit settings Limit IDs above 11 and limit values outside of their allowed value ranges result in a Serial Format Error 6 Using the Serial Interface Page 82 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 9 The limit values set with this command persist only until the controller is next reset or the Apply settings button is next clicked in the Simple Motor Control Center at which point the temporary limit settings are all reinitialized to the hard limit settings Example The following commands all set the reverse deceleration limit limit ID 10 or 0x0A to 500 or Ox1F4 e L10 500 lt CR gt LAH 1F4H lt CR gt L10 1F4H lt CR gt We might receive 0 lt CR gt lt LF gt as a response The leading is a status character that indicates the last command was understood and no errors are currently stopping the motors The following character 0 tells us the temporary limit was set as requested If our Max Deceleration Reverse hard motor limit was below 500 this character would have been 2 which would tell us that the temporary limit was not set as requested rather it was set equal to whatever the hard limit is Get Firmware Vers
57. aximum and Maximum map to a Scaled Value between 0 and 3200 or 3200 if Invert input direction is checked e Raw values between Maximum and Error max map to a Scaled Value of 3200 or 3200 if Invert input direction is checked 5 Configuring Your Motor Controller Page 50 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation By default the scaling is linear but you can change the Scaling degree to use a higher degree polynomial function which gives you better control for low speeds The Error min and Error max parameters should be set so that the input channel s Raw Value is always within that range whenever the input is operating properly One way to do this is to move your input to the minimum position and set Error min to be 10 200 counts lower than the current channel value Similarly move your input to its maximum position and set Error max to be 10 200 counts higher than the current channel value The Minimum and Maximum parameters should be as far apart as possible to maximize the accuracy of your speed control but they should still be close enough that you can reliably reach scaled values of 3200 100 One way to do this is to move your input to its minimum position and set Minimum to be 10 200 counts higher than the current channel value Similarly move your input to its maximum position and set Error max to be 10 200 counts lower than the current channel value
58. bled For information about the serial commands used by this sample code refer to Section 6 2 1 6 7 1 Arduino Examples The Arduino _ https www pololu com product 2191 _ is a popular prototyping platform that is well suited for beginners to the world of embedded programming Arduino boards are based on Atmel s AVR microcontrollers like the Orangutan robot controllers https www pololu com category 8 robot controllers and are essentially programmed in C The Arduino uses its hardware serial or UART lines for programming and for debugging with the Arduino IDE s serial monitor so we do not recommend using these lines to communicate with peripheral serial devices like the Simple Motor Controller Instead we recommend using the SoftwareSerial Arduino R3 top view http arduino cc hu Reference SoftwareSerial library included with the Arduino IDE which lets you use arbitrary I O lines for transmitting and receiving serial bytes The drawback is that software serial requires much more processing time than hardware serial In the following examples we use the SoftwareSerial library to transmit bytes on digital pin 4 and receive bytes on digital pin 3 These examples are written for Arduino 1 0 and will not work with earlier verisons of the IDE 9 These sample programs require the Simple Motor Controller to have a fixed baud rate set to 19200 bps It must also be in Binary serial mode with the CRC Mode set to Disabled Auto
59. c Stamp https www pololu com product 1600 or other logic level serial device allowing for the creation of autonomous self contained systems The following section explains the serial pins in detail see Section 6 for information on using the serial interface ee ee o TXIN daisy chain input Simple High Power Motor Controller 18v15 or 24v12 serial connections 4 Connecting Your Motor Controller Page 34 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation il Simple High Power Motor Controller 18v25 or 24v23 serial connections Serial Connections Overview The pins along the left side of the Simple Motor Controller can be used to communicate with devices with logic level TTL serial interfaces such as microcontrollers As explained in Section 4 1 the Simple Motor Controller uses 3 3V logic but all of the digital pins in the above diagrams everything except for VIN and GND are 5V tolerant which means that the Simple Motor Controller can be used directly with a microcontroller running at 5 V as long as that microcontroller is guaranteed to read a 3 3 V signal as high The Simple Motor Controller uses its RX and TX pins to receive and transmit asynchronous logic level TTL non inverted serial signals with 8 bit characters and one stop bit often expressed as 8 N 1 This is the type of serial typically used by microcontroller UART modules 9 Whenever connecting device
60. can be temporarily modified using the appropriate USB or serial command Only modifications that make the system safer are allowed These temporary changes will only last until the next time the device resets at which point the hard limits will be reloaded See Section 6 2 1 for more details about setting temporary motor limits Configuring Your Motor Controller Page 53 of 108 Nn Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation If you want to enter different limits for the reverse and forward directions check the Asymmetric checkbox Max speed is a number between 0 and 3200 that specifies the maximum speed at which the motor controller will ever drive the motor The default value is 3200 which corresponds to 100 and means there is no limit A value of 0 means that the motor will not be allowed to drive in the specified direction This setting also affects how the Target Speed is computed in RC and Analog modes after mixing is optionally performed a scaled value of 3200 or 3200 maps to the Max speed The Max speed should be zero or it should be greater than the Starting speed Starting speed is a number between 0 and 3200 that specifies the minimum speed at which the motor controller will ever drive the motor The default value is 0 which means there is no minimum so this setting has no effect This setting also affects how the Target Speed is computed in RC or Analog modes after mixing is optionally perf
61. control the motors An example of this can be seen in Section 4 3 The following diagrams show the internal circuitry of the ERR pin in the error case driving high to report an error and in the error free case pulled low and configured as an input Simple Motor Controller Simple Motor Controller Schematic diagram of the Simple Schematic diagram of the Simple Motor Controller ERR pin when the pin Motor Controller ERR pin when the pin is an output i e there are errors is an input i e there are no errors The TXIN Pin in Detail The TXIN pin is a special input that allows multiple Simple Motor Controllers to be chained together without requiring an external AND gate The following diagram shows how multiple motor controllers can be connected to a single microcontroller UART 4 Connecting Your Motor Controller Page 37 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Microcontroller with TTL UART SMC 1 SMC 2 SMC 3 Wiring diagram for controlling multiple Simple Motor Controllers with single TTL serial source such as a microcontroller Inside each Simple Motor Controller an AND gate is used to combine the input from the TXIN pin with the controller s serial transmissions As long as only one chained controller is transmitting at any given time the above method of chaining will funnel the transmissions of all chained devices to a single microcontroller receive line The following
62. cting a Serial Device csoc ec ee 34 4 3 Connecting an RC Receiver s ssia cate Se RAS BS ea a PEM ES a 38 4 4 Connecting a Potentiometer or Analog Joystick 2 2 ee 42 5 Configuring Your Motor Controller 2 ee 47 Sil Input Settings o e es eee Sek eo Ree Be ee ee ee 47 5 1 1 Configuring a Limit or Kill Switch 2 ee 51 5 2 Motor Settings sno tia a ke ek ee ee ee a ew ee ad a ee ed Re 52 5 3 Advanced Settings 4 259 Ses he AWS atk ele Rip eee ee ee ee oe Sek ee De LRR 55 5 4 Upgrading Firmware oaa a ee 58 6 Using the Seral Interface sa sery anit ewe BR AA Ae See eee 60 6 1 Serial Settings 3 cae Soe Pe ee Bee ee PE ee a ee 62 6 2 Binary Commands Asa 2 e244 aoe we a whe bod bees eee Re ee we ee eee 64 6 2 1 Binary Command Reference 2 20 0 0000 ee ee 67 6 3 ASC Commands sa a cia es ge Be ec ay Bok pes Ba eae EG ee ae ee 2A 76 6 3 1 ASCII Command Reference 0 0 0000 2 ee 80 6 4 Controller Variables sas irela doh ge Oe SE Eee Mee bag Wa Pd ghia ee eee 83 6 5 Cyclic Redundancy Check CRC Error Detection 0000000008 90 6 6 Daisy Chaining oya aay a ies SANE BO eo Be es Ae ae a ee 92 6 7 Sample Code cc oa a ee eo ee bh we oe OP ee ee PE oe a a 94 6 7 1 Arduino Examples s sr po ew 4 a ety gi Bhs et ee Ee ew we a A es 94 6 7 2 Orangutan Examples 2 2 ee 98 6 7 3 Cross platform C Example 2 2 2 e 102 6 7 4 Windows C Example 2 ee 105 6
63. ction 4 3 Limit Kkill Switches Unused analog channels can also be used as limit or kill switches When configured as a limit or kill switch if the channel value exceeds more than half of its forward value the switch is activated If you want to use a push button switch for this purpose we recommend using a normally closed NC switch connected in one of the two ways depicted in the diagrams below Simple Motor Simple Motor Controller Controller Analog Interface Analog Interface with internal pull up no internal pull up 3 3V 5S N C Limit Switch N C Limit Switch By using a normally closed limit switch you ensure that if the switch becomes disconnected in some way the controller considers the limit kill switch active and stops the motor The left wiring diagram is simpler because it uses an internal pull up resistor enabled using the Simple Motor Control Center but it can only result in one of two possible states switch active or switch inactive The right wiring diagram above is able to take advantage of the potentiometer disconnection detection feature Pressing the switch activates it releasing it deactivates it and disconnecting it results in a disconnection error or an activated switch depending on which parts of the switch are disconnected The above configurations should work with the default analog channel calibration values but we still recommend you use the Channel Setup Wizard click the Learn b
64. d Serial Manually set speed Serial USB mode only USB mode only a The Manually Set Speed box in R e p Status tab allows you to control 100 BS 100 the speed of your motor over USB by using a scrollbar or by typing in a speed To use this feature the Input Mode configured in the Input Settings tab must be USB Serial and there must be no errors currently stopping the motor You will need to press the Resume button if you have not disabled Safe Start or if you previously pressed the Stop Motor button lt Set speed when slider or entry box are changed Retum slider to zero when it is released I lt 3 Getting Started Page 19 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 3 4 Errors The Simple Motor Controller has several Errors features that stop the motor when Stopping motor Count something is going wrong These are called Safe start violation 526 errors and they can help protect your SS p rT No 5 project from damaging itself Whenever you are having an issue with the controller Command timeout No z you should first check to see what if any Limit kill switch No errors are occurring You can get Low VIN Yes 526 information about the errors by High VIN No 5 e Checking the Errors box in the Status Motor driver error No p tab of the Simple Motor Control Center Over temperature No This is recommended because it gives ERR line high No E
65. d and run the Pololu Simple Motor Control Center This is what the Status tab should look like initially before you have modified any settings or connected anything to the Simple Motor Controller besides USB 3 Getting Started Page 16 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation E Pololu Simple Motor Control Center File Edit View Device Help Connected to 18v15 39FF 7406 2054 3036 49230743 Status input Settings Motor Setangs Advanced Settings Motor Limits Curent Speed 0 00 Target Speed 0 00 Forward Max speed Starting speed Max acceleration Max deceleration Set Speed Set speed when sider or entry box are changed Retum sider to zero when t is released Exc Braking 32 32 Motor stopped because VIN is dsconmected The Status tab in the Simple Motor Control Center should look like this when you first connect the controller to the PC Target Speed and Current Speed The Target Speed is the speed that the motor controller is trying to achieve The Target Speed source is determined by the settings in the Input Settings tab and can come from serial USB commands analog voltages or RC signals The Current Speed is the speed at which the controller is currently your driving your motor There are several reasons why the Current Speed might be different from the Target Speed errors acceleration limits deceleration limits brake duration ma
66. d operations on the devices it was not addressed to If you want to daisy chain several Simple Motor Controllers together you can use a mixture of both protocols If you want to daisy chain the Simple Motor Controller with other devices that use the Pololu protocol you can use the Pololu protocol If you want to daisy chain the Simple Motor Controller with other devices that use the Mini SSC protocol you can use the Mini SSC protocol Secondly assign each device in the project a different device number so that they can be individually addressed by your serial commands For the Simple Motor Controller this can be done in the Input Settings tab of the Simple Motor Control Center The following diagram shows how to connect one master and many slave devices together into a chain Each of the slave devices may be a Simple Motor controller or any other TTL serial device such as a Maestro https www pololu com product 1352 jrk https www pololu com product 1392 qik https www pololu com product 1110 or other microcontroller Pololu USB device Serial devices using or microcontroller Pololu protocol Daisy chaining serial devices using the Pololu protocol An optional AND gate is used to join multiple TX lines 6 Using the Serial Interface Page 92 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation The Simple Motor Controller has a special input called TXIN that eliminates the need for an exter
67. d servo controllers As such you can daisy chain a Simple Motor Controller on a single serial line along with our other serial controllers including additional Simple Motor Controllers and using this protocol send commands specifically to the desired controller without confusing the other devices on the line To use the Pololu protocol you must transmit OxAA 170 in decimal as the first command byte followed by a Device Number data byte The default Device Number for the Simple Motor Controller is 0x0D 13 in decimal but this is a configuration parameter you can change Any controller on the line whose device number matches the specified device number accepts the command that follows all other Pololu devices ignore the command The remaining bytes in the command packet are the same as the compact protocol command packet you would send with one key difference the compact protocol command byte is now a data byte for the command 0xAA and hence must have its most significant bit cleared Therefore the command packet is OxAA device command byte with MSB data byte data byte data byte 170 number cleared 1 2 X3 n 10101010 0XXXXXXX OXXXXXXX OXXXXXXX OXXXXXXX OXXXXXXX For example if we want to set the motor speed to 3200 full speed forward we could send the following byte sequence Hex notation OxAA 0x0D 0x05 0x00 0x64 Decimal notation 170 13 5 0 100 The byte 0x05 is the Set Motor Forward com
68. ds breadboards https www pololu com category 28 solderless breadboards and 0 1 connectors For high power applications that exceed the 15 A rating of the terminal blocks we recommend soldering thick wires directly to a connector free version of the board and using higher current connectors https www pololu com product 925 see the custom connector pictures above Another benefit of the connector free version is flexibility in placement of the power capacitor e g on the other side of the board to accommodate compact installations or to make room for a heat sink The power capacitor has a significant effect on performance the included capacitor is the minimum size recommended and bigger ones can be added if there is space A bigger capacitor might be required if the power supply is poor or far more than about a foot from the controller The pin out diagrams above show where you can connect the included or your own larger power capacitor 4 Connecting Your Motor Controller Page 32 of 108 Pololu Simple Motor Controller User s Guide Logic Power The Simple Motor Controllers use 3 3 V logic but all of the controllers digital inputs are 5V tolerant so it can interface directly with 5V systems The only pins on the board that cannot tolerate 5V are the two analog input channels Al and A2 The simple motor controllers incorporate both a 5V regulator and a 3 3V regulator but the 5V regulator is only used when power is supplied
69. e Motor Controller s virtual serial port can be used in Linux without any special driver installation The virtual serial port is managed by the cdc acm kernel module whose source code you can find in your kernel s source code drivers usb class cdc acm c When you connect the Simple Motor Controller to the PC the virtual serial port should appear as a device with a name like dev ee Garade te fee ener sen ae som aus ore 2001 2015 Pololu Corporation 3 das h tmp eee font ro me j eo reen me te pees a ommen r a ern e omen maae fo T G ai mmi met a AENA E a The Pololu Simple Motor Control Center running under Linux ttyacmo the number depends on how many other ACM devices you have plugged in You can use any terminal program such as kermit to send commands and receive responses on those ports 3 3 Understanding the Control Center Status Tab After installing the software and drivers for the Simple Motor Controller it is a good idea to run the Pololu Simple Motor Control Center and look at the Status tab The Status tab lets you monitor the status of your motor controller in real time and control the speed of the motor The Status tab also shows what errors and limits are affecting your motor controller so it can help you quickly troubleshoot any issues you are having To use the Status tab you should connect your Simple Motor Controller to your PC using a USB cable not include
70. e begins with a single low start bit followed by the bits of the byte least significant bit LSB first Logical ones are transmitted as high 3 3 V and logical zeros are transmitted as low 0 V which is why this format is referred to as non inverted serial The byte is terminated by a stop bit which is the line going high for at least one bit time The Simple Motor Controller supports fixed baud rates of 1099 bps to 2 Mbps and can automatically detect baud rates up to 500 kbps in auto detect baud rate mode You must wait for at least 1 ms after the Simple Motor Controller powers up or is reset before you start sending data Anything sent during this first millisecond is likely to be ignored or incorrectly received 6 Using the Serial Interface Page 61 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 9 Whenever connecting devices remember to wire the grounds together and ensure that each device is properly powered Unpowered devices with a TTL serial port can turn on or partially on drawing power from the serial line which means that extra care must be taken when turning power off and on to reset the devices Note TTL serial is not the same as RS 232 serial You must use an inverter and level shifter such as a MAX232 or a Pololu 23201a Serial Adapter https www pololu com product 126 if you want to interface an RS 232 device with the Simple Motor Controller Connecting an RS
71. e expressed as strings of ASCII digits By default the string is interpreted as a decimal base 10 value but an H can be appended to the end of the string to tell the Simple Motor Controller to interpret it as a hexadecimal base 16 or hex value For example you can represent an argument value of 127 with 127 or 7FH 0x7F is the hex representation of 127 The arguments to the three motor commands F R and B can also be written as percentages by appending a to the end of the argument For example you can represent full motor speed with the argument 3200 or with the argument 100 Termination Characters ASCII mode accepts three different termination characters e Carriage Return A carriage return is the character sent when you press the Enter key in a terminal program It is often written as lt CR gt and has a character value of 13 In C this special character can be written as r e NL Line Feed Also known as new line this character is often written as lt LF gt and has a character value of 12 In C this special character can be written as n e Null Character This character is used to terminate strings in C It is often written as lt NUL gt and has a character value of 0 In C the string abc is comprised of the four characters a b c and lt NUL gt One of the above three characters must be the last character in your ASCII com
72. e settings on the bottom half of the Input Settings tab are all channel specific settings To view or edit them you must first select the desired channel using the list box in the bottom left corner Alternate Use The Alternate Use setting allows you to configure any channel that is not used to control the speed of the motor as a limit or kill switch The available options are e None This channel will not be used for anything special but its Raw and Scaled values can be read using serial or USB e Forward limit switch When the scaled value of the channel is above 1600 50 the limit switch will be considered active and the motor will not be allowed to move forward If the target speed is positive a Limit kill switch error will occur e Reverse limit switch When the scaled value of the channel is above 1600 50 the limit switch will be considered active and the motor will not be allowed to move in reverse If the target speed is negative a Limit kill switch error will occur 5 Configuring Your Motor Controller Page 49 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation e Kill switch When the scaled value of the channel is above 1600 50 the kill switch will be considered active and the Limit kill switch error will occur preventing the motor from moving For example you could use the kill switch feature and the Serial USB input mode to make an autonomous robot that you
73. ed Additionally serial responses from the controller have a CRC byte appended to the end which lets you be more confident that the response was not corrupted by noise Device Number This is the device number 0 127 that is used to address this device in Pololu Protocol and Mini SSC protocol commands This setting is useful when using the Simple Motor Controller with other devices in a daisy chained configuration see Section 6 6 Baud Rate This setting only applies to TTL serial communication via the RX and TX pins it is not relevant for serial communication over the virtual COM port Auto detect baud rate is only available when the Serial Mode is Binary Fixed baud rate is automatically selected when the Serial Mode is ASCII e Auto detect baud rate In this mode the Simple Motor Controller automatically detects the baud rate from the first OxAA 170 baud rate indication byte it receives on the RX line Every time the controller is powered up or reset and every time the Apply settings button is pressed in the Simple Motor Control Center you will need to send a baud rate indication byte before the Simple Motor Controller will accept TTL serial commands Once you send the baud rate indication byte you can check the Status Tab of the Simple Motor Control Center to see what baud rate the controller detected The controller can automatically detect baud rates from 1200 bps to 500 kbps e Fixed baud rate In this mode the S
74. ed long baud if SERIAL PORTS gt 1 Orangutan X2 and SVP users serial set _baud_rate UARTO baud else 6 Using the Serial Interface Page 98 of 108 Pololu Simple Motor Controller User s Guide serial set_baud_rate baud endif void sendBlocking char buffer unsigned char size if SERIAL PORTS gt 1 Orangutan X2 and SVP users serial send _blocking UARTO buffer size else serial send _blocking buffer size endif required to allow motors to move must be called when controller restarts and after any error void exitSafeStart command 0 0x83 sendBlocking command 1 speed should be a number from 3200 to 3200 void setMotorSpeed int speed if speed lt 0 command 0 0x86 motor reverse command speed speed make speed positive else command 0 0x85 motor forward command command 1 speed amp Ox1F command 2 speed gt gt 5 sendBlocking command 3 initialization code called once when the program starts running void setup initialize hardware serial UARTO with baud rate of 115 2 kbps setBaudRate 115200 the Simple Motor Controller must be running for at least 1 ms before we try to send serial data so we delay here for 5 ms delay _ms 5 if the Simple Motor Controller has automatic baud detection enabled we first need to send it the byte OxAA 170 in decimal so tha
75. egister System Time Low System Time High Type signed 16 bit signed 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit Temporary Motor Limits Description Motor target speed 3200 to 3200 requested by the controlling interface Current speed of the motor 3200 to 3200 When Speed 0 this variable indicates how hard the controller is braking with a value from 0 full coast to 32 full brake Otherwise it has a value of OxFF 255 The high byte of this variable is always zero Measured voltage on the VIN pin Board temperature as measured by a temperature sensor near the motor driver Temperatures below freezing are reported as 0 If there is a valid signal on RC1 this variable contains the signal period Otherwise this variable has a value of 0 Value of the controller s baud rate register BRR Convert to units of bps with the equation 72 000 000 BRR In automatic baud detection mode BRR has a value of 0 until the controller has detected the baud rate Two lower bytes of the number of milliseconds that have elapsed since the controller was last reset or powered up Two upper bytes of the number of milliseconds that have elapsed since the controller was last reset or powered up 2001 2015 Pololu Corporation Units internal units internal units 0 coast 32 brake mV 0TG 0 1 m
76. er how to read a variable and how to set the target speed This code will work in Windows if compiled with MinGW but it does not work with the Microsoft C compiler For Windows specific example code that works with either compiler see Section 6 7 4 6 Using the Serial Interface Page 102 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 3 For this example to work the Simple Motor Controller s input mode must be Serial USB the serial mode must be Binary and the CRC Mode must be set to Disabled These are the default settings that the controller is shipped with The controller should be connected to the computer via USB Uses POSIX functions to send and receive data from the virtual serial port of a Pololu Simple Motor Controller NOTE The Simple Motor Controller s Input Mode must be set to Serial USB NOTE You must change the const char device line below include lt fcntl h gt include lt stdio h gt include lt unistd h gt ifdef WIN32 define O_NOCTTY 0 else include lt termios h gt endif define SERIAL ERROR 9999 Reads a variable from the SMC and returns it as number between 0 and 65535 Returns SERIAL ERROR if there was an error The variableId argument must be one of IDs listed in the Controller Variables section of the user s guide For variables that are actually signed additional processing is required see smcGetTargetSpeed
77. er supply s voltage is too high You can set the threshold voltage in the Advanced Settings tab e Motor driver error This error occurs whenever the motor driver chip reports an under voltage or over temperature error by driving its fault line low e Over temperature This error occurs whenever the reading from the temperature sensor is too high You can see the temperature reading in the Conditions box of the Status tab The behavior of this error and the threshold temperatures can be configured in the Advanced tab ERR line high This error occurs whenever there are no other errors but the voltage on the ERR line is high 2 3 5 V This error allows you to connect the error lines of two Simple Motor Controllers together and have both of them stop when either one experiences an error This error can be disabled in the Advanced Settings tab e Serial errors Serial errors are recorded whenever something goes wrong with the serial communication either on the RX TX lines or on the USB virtual COM port If the input mode is Serial USB then a serial error will stop the motor from running until a valid serial command is received or the Resume button is pressed or the native USB Set Speed or Exit Safe Start commands are sent If you are using serial and have not disabled Safe Start mode you will need to send the Exit Safe Start command followed by a Set Speed command to recover from an error and get the motor running again If you are using se
78. er to have automatic baud rate detection enabled or to have a fixed baud rate set to 115200 bps It must also be in Binary serial mode with the CRC Mode set to Disabled Simple Example This example assumes the following connections exist between the Orangutan and the Simple Motor Controller e Orangutan pin PDO to Simple Motor Controller TX e Orangutan GND to Simple Motor Controller GND Pin PDO is the Orangutan s hardware serial receive line and must be connected to the Simple Motor Controller as described above for this sample program to work See Section 4 2 for more information on connecting a serial device to the Simple Motor Controller This program demonstrates how to initiate serial communication with the Simple Motor Controller and how to send commands to set the motor speed For information about the serial commands used by this sample code refer to Section 6 2 1 Note that the Simple Motor Controller must be powered when this Orangutan program starts running include lt pololu orangutan h gt char command 3 These first two functions call the appropriate Pololu AVR library serial functions depending on which Orangutan you are using The Orangutan SVP and X2 have multiple serial ports so the serial functions for these devices require an extra argument specifying which port to use You can simplify this program by just calling the library function appropriate for your Orangutan board void setBaudRate unsign
79. erial print Error Status 0x Serial printin getVariable ERROR STATUS HEX once all other errors have been fixed this lets the motors run again exitSafeStart 6 Using the Serial Interface Page 97 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 6 7 2 Orangutan Examples The Orangutan robot controllers https www pololu com category 8 robot controllers feature user programmable Atmel AVR microcontrollers interfaced with additional hardware useful for controlling robots They are programmable in C or C and supported by the Pololu AVR library https www pololu com docs 0J20 which makes it easy to use the integrated hardware and AVR peripherals such as the UART module Unlike the Arduino the hardware serial lines are completely available on the Orangutans so software serial is not necessary when connecting to serial devices like the Simple Motor Controller Orangutan SVP fully assembled In the following example programs we use the OrangutanSerial functions from the Pololu AVR library to transmit bytes on pin PD1 In the advanced example we use the OrangutanSerial functions to receive bytes on pin PDO and we use the OrangutanLCD functions to report feedback obtained from the Simple Motor Controller See the Pololu AVR library command reference https www pololu com docs 0J18 for more information on these functions 3 This code requires the Simple Motor Controll
80. es which can significantly exceed 24 V when fully charged and are dangerously close to the maximum voltage limits of these lower voltage controllers Using a 24 V battery with an 18vX Simple Motor Controller makes the device much more susceptible to damage from power supply noise or LC voltage spikes Key Features IRC Receiver USB Interface PC e Simple bidirectional control of one DC brush motor TTL Serial interface e 5 5 V to 30 V 18v7 18v15 Microcontroller and 18v25 or 40 V 24v12 Pia Ces esstac and 24v23 operating supply range Analog Interface Joystick Potentiometer Limit Switch e 7A to 25A maximum continuous current output without a heat sink depending on controller model Brushed DC Motor e Four communication or control options 1 USB interface for direct connection to a PC Battery 2 Logic level TTL serial Simple High Power Motor Controller 18v25 or 24v23 simplified interface for direct connection Cagram connection to microcontrollers or other embedded controllers 3 Hobby radio control RC pulse width interface for direct connection to an RC receiver or RC servo controller https www pololu com category 12 re servo controllers 4 0 3 3 V analog voltage interface for direct connection to potentiometers and analog joysticks 1 Overview Page 3 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Simple configuration and calibration over US
81. fter a reset to transmit to the Simple Motor Controller This pin can be left disconnected in most applications RST Input Simple Motor Controller error output This pin outputs high when there is an ERR In Out error that is stopping the motor turning on the red error LED in the process otherwise it is weakly pulled low This pin is documented in more detail below Simple Motor Controller chained transmission input pin Connecting the transmit output of another serial device to this pin will cause that device s TXIN Input TO f SS p transmissions to be output from the Simple Motor Controller s TX pin This pin is documented in more detail below GND Ground connection point Your serial device must share a common ground with the Simple Motor Controller Board power access point This pin is internally connected to the large VIN pad where motor power is supplied and can be used to power other components in the system but it should not be used to supply more than 500 mA This is not a regulated logic level output VIN Output These pins have a 0 1 spacing Simple Wiring Example Connecting to a Microcontroller All you need to control the Simple Motor Controller with a microcontroller is a connection between the microcontroller s TTL serial transmit pin and the Simple Motor Controller s RX pin If you want to get feedback from the controller you can connect the TX pin to the microcontroller s TTL serial receive pin and or
82. get the same result using binary math by bitwise ANDing the speed with 0x1F 31 In C and many other programming languages these operations can be carried out with the following expressions o speed_byte_1 speed 32 or equivalently speed_byte_1 speed amp Ox1F The second speed data byte can be computed by dividing the full 0 3200 speed by 32 discarding the remainder and keeping only the quotient i e turn the division result into a whole number by dropping everything after the decimal point We can get the same result using binary math by bit shifting the speed right five places In C and many other programming languanges these operations can be carried out with the following expressions speed byte 2 speed 32 or equivalently speed_byte_2 speed gt gt 5 6 Using the Serial Interface 2001 2015 Pololu Corporation Page 68 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation This command has no serial response Example If we want to set the motor target speed to half speed forward we can use the above equations to compute that the first speed byte must be the remainder of 1600 32 or 0 and the second speed byte must be the quotient of 1600 32 or 50 Therefore we can send the following compact protocol bytes We Send Command Byte Data Byte 1 Data Byte 2 Compact Protocol 0x85 133 0x00 0 0x32 50 Alternate Interpretation The allowed
83. ght input to channel 2 e None In this mixing mode the Target Speed is calculated as a function of the Scaled Value of the first channel only Analog Channel or RC Channel 1 Left In this mixing mode the Target Speed is calculated as a function of the sum of the Scaled Value of both channels e Right In this mixing mode the Target Speed is calculated as a function of the difference of the Scaled Value of both channels channel minus channel 2 Note that in RC and Analog mode the Target Speed depends not only on the Scaled Values of the channels but also on the Starting Speed and Max Speed parameters as explained in Section 5 2 The table below summarizes all the input and mixing modes you can choose Input Mode Serial USB Analog Analog Analog RC RC RC Mixing Mode N A None Left Right None Left Right Motor speed is calculated from Serial and or USB commands Analog Channel 1 Analog Channel 1 plus Analog Channel 2 Analog Channel minus Analog Channel 2 RC Channel 1 RC Channel 1 plus RC Channel 2 RC Channel 1 minus RC Channel 2 Example Applications Motor controlled by microcontroller or PC Motor controlled by joystick Differential drive vehicle controlled by joystick Differential drive vehicle controlled by joystick Electronic Speed Controller ESC Differential drive RC vehicle Differential drive RC vehicle Th
84. gs tab Press or activate your switch and make sure that the channel value changes significantly If the value does not change then you should double check your connections and settings and try again 7 Click the Learn button for the channel in the Input Settings tab The Channel Setup Wizard will walk you through the steps needed to calibrate your limit switch s scaling parameters 5 2 Motor Settings The Motor Settings tab of the Pololu Simple Motor Control Center allows you to set up limits to protect your system and lets you specify the details of how your motor should be driven 5 Configuring Your Motor Controller Page 52 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Bad Pololu Simple Motor Control Center File Edit View Device Help Connected to 18v15 39FF 6806 3054 3036 1128 0743 mi Starting speed Max acceleration 0 Brake duration ms p Seeetute pte I P HP P E Invert motor direction PWM frequency 21 77 kHz Speed zero brake amount lt Motor Settings tab in the Pololu Simple Motor Control Center Hard Limits The Hard Limits box allows you to set up hard limits on the motion of your motor in order to protect your system and reduce mechanical stress They are called Hard Limits because they are stored in non volatile memory and they are always obeyed However all of them except Starting Speed
85. h a limit switch because the motor will not stop as fast as possible with the limit switch is triggered If an deceleration value of is too fast for your application you can increase the Speed update period to make it slower Brake duration is the time in milliseconds that the motor controller will spend braking the motor Current Speed 0 before allowing the Current Speed to change signs The Forward Brake Duration is the braking time required before switching from forward to reverse from positive to negative speeds The Reverse Brake Duration is the braking time required before switching from reverse to forward from negative to positive speeds The Speed update period is the time in milliseconds between consecutive updates to the Current Speed The default is 1 ms which is the lowest allowed value By increasing the Speed update period you can decrease the effective rate of acceleration and deceleration because the updates will be applied less often The slowest possible acceleration deceleration can be achieved by setting the Speed update period to 100 ms and the acceleration deceleration limit to 1 with this configuration it will take 320 seconds to accelerate from speed 0 to speed 3200 100 or decelerate from speed 3200 to speed 0 The Invert motor direction option lets you switch the meanings of forward and reverse By default Forward means the average voltage on OUTA is greater than the average voltage on OUTB and reverse means
86. imple Motor Controller will only respond to TTL serial signals transmitted at the configured fixed baud rate in units of bits per second or bps The fixed baud rate can be set from 1099 bps to 2 Mbps but the Simple Motor Controller will not be able to keep up with a constant stream of commands at baud rates over 500 kbps if you send commands to the controller faster than it can process them the receive buffer will eventually fill up data will be lost and a Serial RX Overrun Error will be generated Delay TTL serial responses Enabling this feature causes the Simple Motor Controller to wait for approximately 1 ms before transmitting a TTL serial response This is useful when interfacing with devices like the Basic Stamp that use half duplex UARTs and need time to switch from transmit mode to receive mode When this feature is disabled transmission of a response packet begins as soon as possible after the last byte of a command packet is received if that command packet generates a response Command Timeout This setting lets you configure the Simple Motor Controller to shut down the motor if too much time elapses between received commands which could happen if your serial control source gets disconnected or loses power It is located under the Advanced Tab of the Simple Motor Control Center See Section 5 3 for more information on this parameter 6 Using the Serial Interface Page 63 of 108 Pololu Simple Motor Controller User s Guide
87. ing 5V Wiring diagram for connecting an RC receiver to a Simple Motor Controller Using the RC Channels The Simple Motor Controller is constantly reading the two RC channels and making the measured pulse widths available via the USB and serial interfaces even when the controller is not in RC mode For example you can use the serial interface to read the RC channel values while the motor controller is in analog mode The RC channels are read with 0 25 us resolution and RC pulse frequencies from 10 Hz to 333 Hz are permitted A number of settings exist for adjusting what constitutes a valid RC signal Driving a Motor In RC mode the channel values are mapped to motor speed based on the channel calibration values and the mixing mode We recommend your first step after connecting your RC receiver be to use the Quick Input Setup wizard in the Simple Motor Control Center The wizard instructs you to move your transmitter control sticks to their extremes and maps stick full forward right to the maximum forward motor speed the neutral stick to speed zero and the stick full back left to maximum reverse speed Calibration can have a significant impact on performance 4 Connecting Your Motor Controller Page 40 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation If mixing mode is disabled only channel affects motor speed If mixing mode is set to right or left channel 1 is considered the thr
88. inners since they look like character strings rather than seemingly random sets of bytes Also the ASCII protocol makes it easy to send commands to the Simple Motor Controller from a terminal program See Section 6 3 for more information on the ASCII protocol 6 Using the Serial Interface Page 62 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation CRC Mode When enabled the Simple Motor Controller requires a cyclic redundancy check CRC byte at the end of every Binary Mode serial command packet which helps ensure that the controller won t misinterpret noisy commands or act up when presented with a stream of random serial bytes see Section 6 5 for more information on CRCs CRC error detection is only available when the Serial Mode is Binary it is disabled when the Serial Mode is ASCII There are three possible CRC modes e Disabled CRC error detection is not enabled and CRC bytes should not be added to the end of command packets e Commands only The proper CRC byte must be appended to the end of every Binary Mode serial command packet If the CRC byte is not appended or is incorrect a Serial CRC Error is generated Serial responses from the controller do not have a CRC byte appended to the end e Commands and responses The proper CRC byte must be appended to the end of every Binary Mode serial command packet If the CRC byte is not appended or is incorrect a Serial CRC Error is generat
89. ion any input mode Command Format V lt CR gt Description This command prints the Simple Motor Controller product number in decimal and firmware version number the two major firmware version digits followed by the two minor firmware version digits For example the response to this command might be 152 01 00 lt CR gt lt LF gt which indicates a product ID of 152 a major firmware version of 1 and a minor firmware version of 0 Stop Motor any input mode Command Format X lt CR gt Description This command sets the motor target speed to zero and makes the controller succeptible to a safe start violation error if Safe Start is enabled Put another way this command will stop the motor configured deceleration limits will be respected and not allow the motor to start again until the Safe Start conditions required by the Input Mode are satisfied 6 4 Controller Variables The Simple Motor Controller maintains a set of variables that contain real time information about the controller s inputs outputs and state and these variables in conjunction with the user settings determine the behavior of the controller These variables are all displayed in some way under the Status Tab of the Simple Motor Control Center see Section 3 3 and they can all be requested via the serial interface see the Get Variable command in Section 6 2 1 and Section 6 3 1 for use by custom control programs The serial interface reports
90. is next clicked in the Simple Motor Control Center at which point the temporary limit settings are all reinitialized to the hard limit settings Example To set the reverse deceleration limit limit ID 10 to 500 we can use the above equations to compute that limit byte 1 must be the remainder of 500 128 or 116 and limit byte 2 must be the quotient of 500 128 or 3 Therefore we can send the following compact protocol bytes and wait until we have received one byte in response from the Simple Motor Controller or until our receiving function times out which could happen if there is a problem We Send Command Byte Data Byte 1 Data Byte 2 Data Byte 3 Compact Protocol OxA2 162 Ox0A 10 0x74 116 0x03 3 We Receive Response Byte 1 0x00 0 This response tells us the temporary limit was set as requested If our Max Deceleration Reverse hard motor limit was below 500 we would receive a response code of 2 which would tell us that the temporary limit was not set as requested rather it was set equal to whatever the hard limit is 6 Using the Serial Interface Page 74 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Get Firmware Version any input mode Command Format Command Byte Data Byte1 Data Byte 2 Compact Protocol 0xC2 194 Pololu Protocol OxAA 170 device number 0x42 66 Response Format Response Byte 1 Response Byte 2 Response Byte 3 Response Byte 4 p
91. lapsed The period of your RC signal is shown in the Status tab so you can use that to help pick good values for these settings The Bad signal timeout is like an expiration time for the pulses If the RC signal line is corrupted by enough bad pulses that the channel s value is not getting updated then the RC input channel s signal will be considered 5 Configuring Your Motor Controller Page 57 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation invalid after an amount of time equal to the Bad signal timeout has elapsed Increasing this number makes your settings more strict while decreasing it makes them more lenient Miscellaneous The Disable safe start option disables Safe start violation error which is described in Section 3 4 In Serial USB input mode this means that you will no longer have to send Exit Safe Start commands In RC or Analog input mode this means that you will no longer have to center your inputs in order to restart the motor after an error This option makes it more likely that the motor will start when you are not expecting it The Ignore ERR line high option disables the ERR line high error which is described in Section 3 4 This allows your motor to run even if the ERR line is being driven high by some external device The Ignore pot disconnect option disables the disconnect detection for analog channels Enabling this option means that the device will stop toggling the posi
92. led by selecting a CRC Mode of Commands only or Commands and responses in the Input Settings tab of the Simple Motor Control Center In CRC mode the Simple Motor Controller expects an extra byte to be added onto the end of every Binary mode command packet CRC error checking is not available when the serial mode is ASCII The most significant bit of this byte must be cleared and the seven least significant bits must be the 7 bit CRC for that packet If this CRC byte is incorrect a CRC Error will occur and the command will be ignored The Simple Motor Controller will append a CRC byte to the data it transmits in response to serial commands if the CRC mode is Commands and responses 6 Using the Serial Interface Page 90 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation A detailed account of how cyclic redundancy checking works is beyond the scope of this document but you can find more information using Wikipedia http en wikipedia org wiki Cyclic_redundancy_check The CRC computation is basically a carryless long division of a CRC polynomial 0x91 into your message expressed as a continuous stream of bits where all you care about is the remainder The Simple Motor Controller uses CRC 7 which means it uses an 8 bit polynomial and as a result produces a 7 bit remainder This remainder is the lower 7 bits of the CRC byte you tack onto the end of your command packets
93. ler 18v15 Command Port COM5 iE Processors Windows Vista or Windows 7 device manager showing a Simple Motor Controller Device Manager File Action view Help e gt TS h 2 Network Bus Enumerator Pololu USB Devices amp Pololu Simple High Power Motor Controller 18v15 Ports COM amp LPT Pololu Simple High Power Motor Controller 18715 Command Port COM4 Sh Processors B Soanste Navwirac Windows XP device manager showing a Simple Motor Controller Some software will not allow connection to higher COM port numbers If you need to change the COM port number assigned to your USB device you can do so using the Device Manager Bring up the properties dialog for the COM port and click the Advanced button in the Port Settings tab From this dialog you can change the COM port assigned to your device 3 Getting Started Page 15 of 108 Pololu Simple Motor Controller User s Guide 3 2 Installing Linux Drivers and Software You can download the Pololu Simple Motor Control Center SmcCenter and the command line utility SmcCmd for Linux here Simple Motor Controller Linux Software https www pololu com file download smc linux 101119 tar gz file_id 03411 115k gz Unzip the tar gzip archive by running tar xzvf followed by the name of the file After following the instructions in README txt you can run the programs by executing smcCenter and SmcCma The Simpl
94. ler detects that they are disconnected If you do not intend to use this channel you do not need to worry about this message Otherwise to correct this situation make sure that all three pins of your potentiometer or analog joystick are connected correctly to the three analog interface pins see Section 4 4 The controller toggles the power supply on the Analog pins in order to detect when your potentiometer is disconnected This feature can be turned off in the Advanced tab in which case you will not see the Invalid disconnected message e Invalid signal This message is shown for RC channels when the controller detects no signal or a bad signal on the RC input If you do not intend to use this channel you do not need to worry about this message Otherwise to correct this situation make sure that your RC receiver is powered and connected correctly see Section 4 3 and check your RC pulse detection settings in the Advanced tab e Invalid too high and Invalid too low These messages are shown for Analog channels when the voltage read on the Al or A2 pin is outside of the normal range as specified by the Error min and Error max parameters for that channel in the Input Settings tab To correct this error you can re configure the range of your analog input by clicking the Learn button for that channel or you can manually adjust the scaling parameters e Invalid high signal and Invalid low signal These messages are shown f
95. ller is running and is not reported under the Status Tab of the Simple Motor Control Center You can view it in the Device Information window of the Control Center which is available from the Device menu and for the first two seconds after start up the yellow status LED flashes a pattern that indicates the last reset source see Section 3 5 Reset 0x04 4 RST pin pulled low by external source o Flags 0x0C 12 Power reset VIN got too low or was disconnected e 0x14 20 Software reset by firmware upgrade process e 0x24 38 Watchdog timer reset should never happen this could indicate a firmware bug RC Channel Inputs The raw and scaled signals measured on the RC channel inputs are always available through serial variable requests which allows programs using the serial interface to factor the channel inputs into their motor control algorithms If no valid signal is detected the raw channel value is reported as OxFFFF 65535 and the scaled channel value is reported as 0 The Simple Motor Controller is always reading the RC input channels even when the Input Mode is not RC 6 Using the Serial Interface Page 86 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation ID Name Type Description Units RCl 4 Unlimited unsigned The positive pulse width of the signal on RC channel 1 This value is 0 25 Raw 16 bit OxFFFF 65535 if no valid signal is detected ee Value RCI Raw
96. log joystick allowing for simple manual motor control e g easily control motor speed with a knob The analog inputs can serve several functions from directly controlling the motors Analog input mode to sending signals to an autonomous robot Serial USB mode to providing limit or kill switch inputs any input mode The Simple Motor Controller can derive motor speed from a single analog input channel or it can mix the signals on both analog channels to generate the motor speed which makes intuitive throttlet steering control of a differential drive robot possible using a pair of Simple Motor Controllers Typical analog voltage sources can be powered directly from the Simple Motor Controller C E LELE at Tes Potentiometer Potentiometer Potentiometer Potentiometer Analog input channel 1 Analog input channel 2 potentiometer output potentiometer output Simple Motor Controller 18v7 analog connections 4 Connecting Your Motor Controller Page 42 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Potentiometer Potentiometer Potentiometer Potentiometer Analog input channel 1 Analog input channel 2 potentiometer output potentiometer output Simple High Power Motor Controller 18v15 or 24v12 analog connections Sled ce LEd gt eh S2 tr pr ri s s gt i io E E E Potentiometer Potentiometer Analog voltage input channels potentiometer
97. lolu com docs 0J41 _ supports Windows and Linux and includes the source code for W SmcExampiel in Views Basc NET sF SmcExamplel in C e SmcExamplel a simple example application that uses native USB and has three buttons for setting the motor speed Versions of this example are available in C Visual Basic NET and Visual The Pololu USB SDK contains example code for C the Simple Motor Controller in C Visual C and Visual Basic NET e SmcExample2 an example graphical application that has a scrollbar for setting the motor speed over native USB written in C e SmcCmd a command line utility for configuring and controlling the Simple Motor Controller written in C e Smc A NET class library that enables native USB communication with the Simple Motor Controller written in C You can modify the applications in the SDK to suit your needs or you can use the class library to integrate the Simple Motor Controller in to your own applications Virtual Serial Port Almost any programming language is capable of accessing the Simple Motor Controller s virtual COM port We recommend the Microsoft NET framework which is free to use and contains a SerialPort class that makes it easy to read and write bytes from a serial port You can download Visual Studio Express for either C C or Visual Basic and write programs that use the SerialPort class to communicate with the Simple Motor Controller You will need to set the
98. low One potential problem with this approach is that if there is an error e g the battery becomes disconnected then the motor will start running immediately when the error has been resolved e g the battery is reconnected If you want to prevent your motor from starting up unexpectedly after the controller has recovered from an error then you should only send an Exit Safe Start command after either waiting for user input or issuing a warning to the user Motor Forward Serial USB input mode only Command Format Command Byte Data Byte1 Data Byte 2 Data Byte3 Data Byte 4 Compact Protocol 0x85 133 speed byte 1 speed byte 2 Compact Alternate Use 0x85 133 0 speed Pololu Protocol OxAA 170 device number 0x05 5 speed byte 1 speed byte 2 Pololu Alternate Use OxAA 170 device number 0x05 5 0 speed Description This command lets you set the full resolution motor target speed in the forward direction The motor speed must be a number from 0 motor stopped to 3200 motor forward at full speed and is specified using two data bytes The first data byte contains the low five bits of the speed and the second data byte contains the high seven bits of the speed The first speed data byte can be computed by taking the full 0 3200 speed modulo http simple wikipedia org wiki Modular_arithmetic 32 which is the same as dividing the speed by 32 discarding the quotient and keeping only the remainder We can
99. low it for the amount of time specified by the Low VIN timeout The Low VIN error will stop occurring when the voltage on the VIN line rises above the Low VIN startup voltage If you are using a battery that can be damaged by over discharging we recommend setting your Low VIN shutoff to an appropriate value so that your motors will shut down when the battery voltage gets too low For example if you are using a Lithium Polymer Li Po battery it would be good to set a Low VIN Shutoff to something like 3 0 V or 3 5 V multiplied by the number of cells in your battery You should also consult your battery s specifications and adjust your Low VIN shutoff based on how much current your motor draws and how careful you want to be If VIN exceeds the High VIN shutoff level a High VIN error will occur This error is different from the other errors it instantly shuts down the motors and goes in to full braking mode regardless of your deceleration and 5 Configuring Your Motor Controller Page 56 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation speed zero brake amount settings This means that if you are using the controller in a differential drive vehicle and your vehicle is being pulled down a hill by gravity the extra voltage generated by the motors might trigger a VIN error and the controller would attempt to stop your robot s descent by braking The VIN multiplier offset is a calibration factor used in com
100. lt transmit these seven bits as your CRC byte when talking to the Simple Motor Controller with CRC enabled If you have never encountered CRCs before this probably sounds a lot more complicated than it really is The following example shows that the CRC 7 calculation is not that difficult For the example we will use a two byte sequence 0x83 0x01 Steps 1 amp 2 write as binary least significant bit first add 7 zeros to the end of the message CRC 7 Polynomial 1000100 1 message 11000001 10000000 0000000 Steps 3 4 amp 5 10001001 i11000001 XOR10001001 RoR IPO OSITO 20 0 6 Using the Serial Interface Page 91 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation shift gt 1000100 1 1 0 0 0 0 0 0 1000 0 0 10 0 0 0 0 1000100 1 0 0 0 0 00 0 0 0 1 0 0 0 0 0 1000100 010 0 0 00 0 0 0 10 0 0 0 0 1000100 1 0 0 0 0x17 So the full command packet we would send with CRC enabled is 0x83 0x01 0x17 6 6 Daisy Chaining This section is a guide to integrating the Simple Motor Controller in to a project that has multiple TTL serial devices that use a compatible protocol First of all you will need to decide whether to use the Pololu protocol the Mini SSC protocol or a mix of both see Section 6 2 You must make sure that no serial command you send will cause unintende
101. mand 0x85 with its most significant bit cleared Mini SSC Protocol The Simple Motor Controller also responds to the Scott Edwards Mini SSC protocol a simple three byte serial protocol commonly used by servo controllers This protocol allows you to control up to 254 different motors by chaining multiple motor controllers together Since it only takes three serial bytes to set the speed of one motor this protocol is good if you need to send many commands rapidly to multiple motor controllers The Mini SSC protocol is to transmit OxFF 255 in decimal as the first command byte followed by a Device Number byte and an 8 bit motor speed byte If you think of the available motor speeds as ranging from 127 to 127 the motor speed byte is this signed speed value offset by 127 Therefore A speed byte of 0 results in full speed reverse a speed byte of 127 results in speed 0 motor stopped and a speed byte of 254 results in full speed forward The command packet is OxFF 255 device number 0 254 speed byte 0 254 11111111 XXXXXXXX XXXXXXXX For example if we want to set the speed of device 13 to approximately half speed forward 63 127 190 we could send the following byte sequence 6 Using the Serial Interface Page 65 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Hex notation OxFF 0x11 OxBE Decimal notation 255 13 190 The Device Number byte and Speed byte can be any value except 25
102. mand sets the motor target speed in the forward direction based on the specified low resolution 7 bit Speed byte The Speed byte is a number from 0 motor stopped to 127 motor forward at full speed This command has no serial response Example To set the motor target speed to approximately half speed forward 63 we could send the following compact protocol bytes We Send Command Byte Data Byte 1 Compact Protocol 0x89 137 0x3F 63 Motor Reverse 7 Bit Serial USB input mode only Command Format Command Byte Data Byte1 Data Byte 2 Data Byte 3 Compact Protocol 0x8A 138 speed Pololu Protocol OxAA 170 device number 0x0A 10 speed Description This command sets the motor target speed in the reverse direction based on the specified low resolution 7 bit Speed byte The Speed byte is a number from 0 motor stopped to 127 motor reverse at full speed This command has no serial response Set Speed Mini SSC Serial USB input mode only Command Format Command Byte Data Byte1 Data Byte 2 Mini SSC Protocol OxFF 255 device number speed Description This is the Mini SSC Protocol command for setting the motor speed This command has no serial response See Section 6 2 for complete documentation of this command Motor Brake Serial USB input mode only Command Format Command Byte Data Bytel Data Byte2 Data Byte 3 Compact Protocol 0x92 146 brake amount Pololu Protocol OxAA
103. mand string Responses Any ASCII mode command string that contains more than just a termination character will generate a serial response from the Simple Motor Controller The first character of the response gives you information about the status of the Simple Motor controller it can be one three possible characters 6 Using the Serial Interface Page 77 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Status Character Meaning The last command was understood and no errors are stopping the motor The last command was understood and errors are stopping the motor P The last command was not understood a Serial Format Error has occurred 7 J If the command sent responds with data e g the Get Variable command the data follows the status character as a decimal base 10 string of ASCH digits The ASCII mode serial response is always terminated by a carriage return lt CR gt followed by a line feed lt LF gt For example if we send a Motor Forward command while no errors are stopping the motor the response would be lt CR gt lt LF gt If we send a Get Variable command while errors are stopping the motor the response might be 123 lt CR gt lt LF gt which would indicate that the requested variable has a value of 123 9 Commands that consist only of termination characters do not result in a serial response from the Simple Motor Controller All other commands e
104. mmobilize an autonomous robot from a distance using an RC Transmitter and Receiver To configure your Simple Motor Controller to use a limit or kill switch follow these steps 1 Decide what channel you are going to connect your limit switch to and connect it to that channel as described in Section 4 4 2 If you are using an Analog channel for your limit switch and you decide to use the internal pull up instead of supplying an external one check the Enable pull up resistor box for that channel in the Input Settings tab 3 If you have chosen a wiring configuration that make it impossible for the controller to detect when your switch is disconnected check Ignore pot disconnect box in the Advanced Settings Disconnect detection works by toggling power to the analog power pins and making sure that this toggling has an effect on the voltage on the sigal pin A1 or A2 If you have wired your switch such that the analog power pin is not connected to the signal pin you will need to do this 5 Configuring Your Motor Controller Page 51 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 4 Select the desired Alternate Use for the limit switch channel This determines whether it will be a Forward Limit Switch Reverse Limit Switch or Kill Switch See Section 5 1 for details about the Alternate Use 5 Click Apply Settings 6 Look at the current channel value label in the Input Settin
105. nal AND gate the AND gate is built in to the Simple Motor Controller To make a chain of devices using the TXIN input connect them like this Pololu USB device Serial devices using or microcontroller Pololu protocol 1 TINN TAIN Daisy chaining serial devices that have a TXIN input For additional connection diagrams and more information about the TXIN pin see Section 4 2 Connections Connect the TX line of your controlling device to the RX lines of all of the slave devices Sent commands will then be received by all slaves When receiving serial responses from multiple slaves each device should only transmit when requested so if each device is addressed separately multiple devices will not transmit simultaneously However the TX outputs are driven high when not sending data so they cannot simply be wired together Instead you can use an AND gate as shown in the diagram to combine the signals or you can use the TXIN pin as described above if the device has one Note that in many cases receiving responses is not necessary and the TX lines can be left unconnected 9 Whenever connecting devices remember to wire the grounds together and ensure that each device is properly powered Unpowered devices with a TTL serial port can turn on or partially on drawing power from the serial line which means that extra care must be taken when turning power off and on to reset the devices Sending commands The Pololu Pro
106. nation circuit BEC jumper can power enable mixed RC control of Dagu Wild the RC receiver with 5 V or 3 3 V Thumper 4WD all terrain chassis e Analog features 0 8 mV 12 bit measurement resolution Works with 0 to 3 3 V inputs Optional potentiometer joystick disconnect detection Two analog channels allow for single stick mixed motor control making it easy to use two simple motor controllers in tandem on a joystick controlled differential drive robot o Analog channels can be used in any mode as limit or kill switches Simple Motor Controller Comparison Table The Simple Motor Controllers are available in several input voltage ranges and output current ranges 1 Overview Page 5 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Absolute max connectors installed Available with Y Yes voltage Recommended max 24 V 24 V 34 V 24 V voltage Max continuous current w o 7A 15A 12A 25A heat sink Width 1 1 2 8 cm 1 1 2 8 cm 1 1 2 8 cm 1 2 3 1 cm 1 2 3 1 cm Length 2r SFS iem 2A 53 E 2n Cm AE SR G DE 5 CI Weight 7O 7g Y No 1 We do not recommend using the 18v7 18v15 or 18v25 versions with 24 V batteries which can significantly exceed 24 V when fully charged The 24v12 and 24v23 are the much more appropriate controller for 24 V applications 2 This is the
107. nd CRC byte Disconnect use 0x prefix for hex e g you can write 128 or 0x80 single byte OxC2 Send single byte 2 byte command 0x41 3 byte command 0x85 Jf l Send 3 byte command 4 byte command Send 4 byte command 5 byte command Send 5 byte command 6 byte command Send 6 byte command Sent Received data hex 11 15 56 AM sent C2 received 98 l 00 oO O1 r 11 16 35 AM sent 85 00 32 11 17 22 AM sent Al 18 received 1F O1 r Sending Binary Compact Protocol commands to the Simple Motor Controller with the Pololu Serial Transmitter utility 6 2 1 Binary Command Reference Exit Safe Start Serial USB input mode only Command Format Command Byte Data Byte1 Data Byte 2 Compact Protocol 0x83 131 Pololu Protocol OxAA 170 device number 0x03 3 Description If the Input Mode is Serial USB and you have not disabled Safe start protection then this command is required before the motor can run Specifically this command must be issued when the controller is first powered up after any reset and after any error stops the motor This command has no serial response 6 Using the Serial Interface Page 67 of 108 Pololu Simple Motor Controller User s Guide If you just want your motor to run whenever possible you can transmit Exit Safe Start and motor speed commands regularly The motor speed commands are documented be
108. nguages than the Binary mode responses Command Format ASCII commands consist of a command string which is typically a single letter followed by a comma separated list of numbers representing the arguments to the command Not all commands take arguments and only one command Set Motor Limit takes multiple arguments All commands must be terminated by a special termination character such as a carriage return lt CR gt Expressed generally the format is command string argument 1 argument 2 termination character For example to command the motor to drive forward at speed 3200 full speed we could send the following ASCII command F3200 lt CR gt Here the command string is F the argument string is 3200 and the termination character is lt CR gt 3 ASCII commands are case insensitive and white space is ignored so F3200 lt CR gt has the same effect as f 3200 lt CR gt 6 Using the Serial Interface Page 76 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation The specific commands are documented in Section 6 3 1 Command Strings The following table lists all of the available command strings Command String Command Name GO Exit Safe Start pe Motor Forward RP Motor Reverse B Motor Brake D Get Variable i Set Motor Limit coy Get Firmware Version Xe Stop Motor Argument Strings Command arguments ar
109. nt Kit https www pololu com docs 0J41 Optional CRC error detection to eliminate communication errors caused by noise or software faults Optional command timeout shut off motors if communication ceases Supports automatic baud rate detection from 1200 bps to 500 kbps or can be configured to run at a fixed baud rate 1 Overview Page 4 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Supports standard compact and Pololu protocols as well as the Scott Edwards Mini SSC protocol and an ASCII protocol for simple serial control from a terminal program Optional serial response delay for communicating with half duplex controllers such as the Basic Stamp Controllers can be easily chained together and to other Pololu serial motor and servo controllers to control hundreds of motors using a single serial line e RC features 1 4 us pulse measurement resolution Works with RC pulse frequencies from 10 to 333 Hz Configurable parameters for determining what constitutes an acceptable RC signal Two RC channels allow for single stick mixed motor control making it easy to use two simple motor controllers in tandem on an RC controlled differential drive robot e RC channels can be used in any mode as limit or kill switches e g use an RC receiver to trigger a kill switch on your autonomous robot a ee a i Two Pololu Simple Motor Controllers Battery elimi
110. nt if abruptly switched from full speed in one direction to full speed in the other direction Occasionally electrical noise from a motor can interfere with the rest of the system This can depend on a number of factors including the power supply system wiring and the quality of the motor If you notice parts of your system behaving strangely when the motor is active e g corrupted serial data bad RC pulses noisy analog voltage readings or the motor controller randomly resetting consider taking the following steps to decrease the impact of motor induced electrical noise on the rest of your system 1 Solder a 0 1 uF ceramic capacitor https www pololu com product 1166 across the terminals of your motor or solder one capacitor from each terminal to the motor case For the greatest noise suppression you can use three capacitors one across the terminals and one from each terminal to the case 2 Make your motor leads as thick and as short as possible and twist them around each other It is also beneficial to do this with your power supply leads 3 Route your motor and power leads away from your logic connections if possible 4 Place decoupling capacitors also known as bypass capacitors across power and ground near any electronics you want to isolate from noise Power and Motor Connectors Simple High Power Motor Controller 18v25 or 24v23 18v7 fully assembled fully assembled with included hardware installed
111. ntroller User s Guide for i 0 i lt 256 i CRCTable i getCRCForByte i unsigned char getCRC unsigned char message unsigned char length unsigned char i cre 0 for i 0 i lt length i cre CRCTable cre message i return crc int main unsigned char message 3 0x83 0x01 0x00 nte is Je buildCRCTable message 2 getCRC message 2 for i 0 i lt sizeof message i for J 07 J lt 87 JFF printf d message i gt gt j 2 prirneet lt 3 printf yny 2001 2015 Pololu Corporation 6 Using the Serial Interface Page 107 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 7 Writing PC Software to Control the Simple Motor Controller There are two ways to write PC software to control a Simple Motor Controller the native USB interface and the virtual serial port The native USB interface provides more features than the serial port such as the ability to change configuration parameters and select the Simple Motor Controller by its serial number Also the USB interface allows you to recover more easily from temporary disconnections The virtual serial port interface is easier to use if you are not familiar with programming and it can work with existing software programs that use serial ports such as LabView Native USB Interface The Pololu USB Software Development Kit https www po
112. ntroller will use to calculate the Target Speed of the motor The available options are e Serial USB In this input mode the Target Speed is specified by serial or USB commands and the Target Speed is reset to zero whenever there is an error This is the default input mode e Analog In this input mode the Target Speed is determined by the voltages measured on the analog signal lines A1 and optionally A2 if you want to use mixing e RC In this input mode the Target Speed is determined by the pulse widths measured on the RC signal lines RC1 and optionally RC2 if you want to use mixing Regardless of which input mode you choose the Analog and RC input channels will always be measured those channels can be used as limit or kill switches if they are not controlling the speed of the motor and their values can be retrieved using the Get Variable serial command Mixing Mode If you have chosen Analog or RC as the Input Mode the Mixing Mode setting specifies whether to use mixing and what type of mixing it is 5 Configuring Your Motor Controller Page 48 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation The primary use of mixing is for controlling a motor on a differential drive robot You can use one Simple Motor Controller for each motor on the robot and feed the same inputs in to both of them We recommend connecting the throttle forward reverse input to channel 1 and the steering left ri
113. o digital pin 6 to Simple Motor Controller ERR e Arduino GND to Simple Motor Controller GND There is nothing special about Arduino pins 3 through 6 you can use any free digital pins other than 0 and 1 the Arduino s hardware serial lines if you change the pin definitions at the top of the sample program accordingly See Section 4 2 for more information on connecting a serial device to the Simple Motor Controller 6 Using the Serial Interface Page 95 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation This program demonstrates how to initiate serial communication with the Simple Motor Controller and how to send commands to set the motor speed read variables and change the temporary motor limits For information about the serial commands used by this sample code refer to Section 6 2 1 It will be more interesting if you have input power and a motor connected to your Simple Motor Controller see Section 4 1 but you can see some interesting things even without a motor connected by using the Status tab of the Simple Motor Control Center application to monitor the effect this sketch has on the controller s variables see Section 3 3 include lt SoftwareSerial h gt define rxPin 3 pin 3 connects to SMC TX define txPin 4 pin 4 connects to SMC RX define resetPin 5 pin 5 connects to SMC nRST define errPin 6 pin 6 connects to SMC ERR SoftwareSerial smcSerial SoftwareSerial rxPin txPin
114. onse The leading is a status character that indicates the last command was understood and no errors are currently stopping the motors The rest of the characters before the carriage return lt CR gt and new line lt LF gt characters are an ASCII representation of a decimal base 10 number This particular variable has units of 0 1 C which would mean that the board temperature is 28 6 C Set Motor Limit any input mode Command Format L lt limit_id gt lt limit_value gt lt CR gt Description This command lets you change the temporary motor limit variables documented in Section 6 4 Limit IDs from 0 to 3 are affect both forward and reverse limits equally they are symmetric Limit IDs from 4 to 7 affect only forward limits and limit IDs from 8 to 11 affect only reverse limits The following table provides the limit IDs for all of the temporary motor limit variables along with the allowed limit values 6 Using the Serial Interface Page 81 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation ID Name Allowed Values Units 0 or 4 Max Speed Forward 0 3200 0 0 3200 100 1 or 5 Max Acceleration Forward 0 3200 0 no limit sa his update period 2 or 6 Max Deceleration Forward 0 3200 0 no limit Apend por update period 3 or 7 Brake Duration Forward 0 16384 4 ms 0 or 8 Max Speed Reverse 0 3200 0 0 3200 100
115. or RC channels when the pulse width measured on the RC1 or RC2 pin is outside of the normal range as specified by the Error min and Error max parameters for that channel in the Input Settings tab To correct this error you can re 3 Getting Started Page 18 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation configure the range of your RC input by clicking the Learn button for that channel or you can manually adjust the scaling parameters Conditions The Conditions box in the Status tab shows miscellaneous information about the current state of the controller e VIN This is the voltage of your power supply measured on the VIN line When your power supply is disconnected this should read 0 0 V This reading is continually compared to the VIN thresholds in the Advanced Settings tab and will generate an error and shut down the motor if it passes these thresholds This allows a properly configured controller to avoid over discharging your batteries e Temperature This is a measurement of the temperature of the device This reading is used prevent damage to the device by shutting down the motor when the board gets too hot the over temperature threshold is can be adjusted in the Advanced Settings tab Please note that this product can get hot enough to burn you during normal operation Take care when handling this product or other components connected to it Parts of the board be significantly hotte
116. or more information on connecting a serial device to the Simple Motor Controller This program demonstrates how to initiate serial communication with the Simple Motor Controller and how to send commands to set the motor speed read variables and change the temporary motor limits For information about the serial commands used by this sample code refer to Section 6 2 1 It will be more interesting if you have input power and a motor connected to your Simple Motor Controller see Section 4 1 but you can see some interesting things even without a motor connected by using the Status tab of the Simple Motor Control Center application to monitor the effect this program has on the controller s variables see Section 3 3 include lt pololu orangutan h gt char command 4 define resetPin IO CO pin PCO connects to SMC nRST define errPin IO Cl pin PC1 connects to SMC ERR some variable IDs define ERROR STATUS 0 define LIMIT STATUS 3 define TARGET SPEED 20 define INPUT VOLTAGE 23 define TEMPERATURE 24 some motor limit IDs define FORWARD ACCELERATION 5 define REVERSE ACCELERATION 9 define DECELERATION 2 These first three functions call the appropriate Pololu AVR library serial functions depending on which Orangutan you are using The Orangutan SVP and X2 have multiple serial ports so the serial functions for these devices require an extra argument specifying which port to use You can simplify this program by j
117. or sending int smcSetTargetSpeed int fd int speed unsigned char command 3 if speed lt 0 command 0 0x86 Motor Reverse speed speed else command 0 0x85 Motor Forward command 1 command 2 speed amp Ox1F speed gt gt 5 amp Ox7F if write fd command sizeof command 1 perror error writing return SERIAL ERROR return 0 int main Open the Simple Motor Controller s virtual COM port const char device dev ttyACM0 Linux const char device USBSERO00 Windows COM6 also works const char device dev cu usbmodemfal21 Mac OS X int fd open device O_RDWR O_NOCTTY if fd 1 perror device return 1 ifdef WIN32 _setmode fd _O BINARY else struct termios options tcgetattr fd amp options options c_lflag amp ECHO ECHONL ICANON ISIG IEXTEN options c_oflag amp ONLCR OCRNL tcsetattr fd TCSANOW amp options endif smcExitSafeStart fd printf Error status 0x 04x n smcGetErrorStatus fd int speed smcGetTargetSpeed fd printf Current Target Speed is d n speed int newSpeed speed lt 0 3200 3200 printf Setting Target Speed to d n newSpeed smcSetTargetSpeed fd newSpeed close fd return 0 6 Using the Serial Interface Page 104 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Polol
118. ormed a scaled value of 1 means the Target Speed equals the Forward Starting Speed and a scaled value of 1 means the Target Speed equals the inverse negation of Reverse Starting Speed The starting speed parameter allows you to save some energy by never driving the motor at speeds that are too low to actually make the motor turn It can also make your joystick control be more accurate and responsive because the motor can start moving as sooner as the stick leaves the neutral area Max acceleration is a number between 0 and 3200 that specifies how much the magnitude absolute value of the motor speed is allowed to increase every speed update period The default value is 0 which means there is no limit An acceleration limit can help reduce mechanical stress and help reduce current spikes when the motor is starting up If an acceleration value of is too fast for your application you can increase the Speed update period to make it slower Max deceleration is a number between 0 and 3200 that specifies how much the magnitude absolute value of the motor speed is allowed to decrease every speed update period The default value is 0 which means there is no limit A deceleration limit can help reduce mechanical stress and help reduce current spikes when the motor is decelerating Note that deceleration limits apply even when there is an error stopping the motor depending on your setup it might not be a good idea to use deceleration in conjunction wit
119. otor turns in the opposite direction 6 Using the Serial Interface Page 80 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Motor Brake Serial USB input mode only Command Format B lt brake_amount gt lt CR gt Description This command causes the motor to immediately brake by the specified amount configured deceleration limits are ignored The argument brake_amount can be an integer from 0 maximum coasting to 32 full braking or an integer percentage from 0 to 100 You can represent the brake amount in hex by putting an H at the end of the number If the argument brake amount is outside the allowed range a Serial Format Error occurs Error Examples The following commands all make the motor brake as hard as possible e B32 lt CR gt e B100 lt CR gt e B20H lt CR gt Get Variable any input mode Command Format D lt variable_id gt lt CR gt Description This command lets you read a variable from the Simple Motor Controller See Section 6 4 for a list of all of available variables The value of the requested variable is transmitted as an ASCII encoded decimal number If the argument variable id is between 41 and 127 a Serial Format Error occurs Example The following commands both request the board temperature variable ID 24 or 0x18 D24 lt CR gt D18H lt CR gt We might receive 286 lt CR gt lt LF gt as a resp
120. ottle input and channel 2 is considered the steering input Left mixing mode obtains motor speed by summing the throttle and steering channels CH1 CH2 while right mixing mode obtains motor speed by taking the difference of the throttle and steering channels CH1 CH2 To see why this makes sense consider a differential drive robot a robot with a motor on each side with a left motor driven by a Simple Motor Controller in left mixing mode and a right motor driven by a Simple Motor Controller in right mixing mode When throttle is full forward CH1 max and steering is neutral CH2 0 left and right mixed motors are both driven forward at full speed and the robot goes forward When throttle is neutral CH1 0 and steering is full right CH2 max the left mixing results in motor forward at full speed while right mixing results in motor reverse at full speed so the robot turns right As demonstrated above using both RC channels in mixing mode makes it possible to combine two RC controlled Simple Motor Controllers to achieve single stick mixed control of a differential drive robot The following diagram shows how to connect two such motor controllers together RC receiver SMC 1 RC Input Mode RC Input Mode Mix Mode Left Mix Mode Right Wiring diagram for pairing two Simple Motor Controllers with RC channel mixing You should configure the controller that drives the right motor as mixing mode right and the controlle
121. perature 32C Baud Rate 115200 Starting speed N A N A RC Period ms 20 Max acceleration 4 4 Max deceleration 10 Brake duration ms 0 200 Stoppang motor Count Raw Value Scaled Status 1839 ys 66 09 Vaid 1364 us 23 47 Vaid 1637 mV 0 00 Vaid Anaiog2 Mmv 10003 Toae No No No No No No No No No No Manually set speed Serial USB mode only 100 73 25 Set Speed V Set speed when sider or entry box are changed V Retum sider to zero when t is released erm Diving Status tab in the Pololu Simple Motor Control Center 4 Connecting Your Motor Controller 2001 2015 Pololu Corporation Page 33 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Before you can move the motor you will probably need to click the green Resume button in the lower left corner to clear the safe start violation If the Resume button is grayed out there are errors that are preventing the motor from moving See Section 3 4 for information on how to identify and fix errors 9 Safe Start is an optional feature enabled by default that makes it less likely that the motor will start moving unexpectedly 4 2 Connecting a Serial Device The serial pins make it possible to connect the Simple Motor Controller to a microcontroller e g an Orangutan Robot Controller https www pololu com category 8 robot controllers Arduino https www pololu com product 2191 Or Basi
122. ptable level The channel pins have a 0 1 spacing which means that a female female servo extension cable https www pololu com product 780 can be used to connect a potentiometer or analog joystick to the motor controller board Simple Wiring Example Connecting to a Potentiometer Simple Motor Controller GND Analog Interface S Potentiometer Joystick 1K to 10K recommended Wiring diagram for connecting a potentiometer or joystick to a Simple Motor Controller Using the Analog Channels The Simple Motor Controller is constantly sampling the two analog channels and making the measured voltages available via the USB and serial interfaces even when the controller is not in analog mode For example you can use the serial interface to read the analog channel values while the motor controller is in RC mode The analog channels are read with 12 bit 0 8 mV resolution Driving a Motor In analog mode the channel values are mapped to motor speed based the channel calibration values and the mixing mode We recommend your first step after connecting your analog voltage source be to use Quick Input Setup Wizard in the Simple Motor Control Center The wizard instructs you to move your inputs to their extremes and maps one extreme to the maximum forward motor speed the neutral position to speed zero and the other extreme to maximum reverse speed Calibration can have a significant impact on performance If mixing mode is disabled
123. puting VIN The default value of 0 should work fine for most purposes If you have a multimeter or another accurate way of measuring voltage you can click the Learn button to have the software automatically set this number for you If you find that the VIN reading shown in the Status tab is too high you should decrease this number If it is too low you should increase this number Over temperature Response The Simple Motor Controller monitors its temperature using a sensor near the MOSFETs and protects itself from burning up by generating an error when the temperature is too high The Simple Motor Controller has two modes for over temperature response e Abrupt shutoff with hysteresis This is the default mode In this mode the Over temperature error will start occurring when the temperature exceeds the Over temperature maximum and will keep until the temperature drops below the Over temperature minimum In this mode it will be obvious when you are having temperature issues because your motor will shut down completely while your motor controller cools off e Gradual limiting In this mode whenever the temperature is between the Over temperature minimum and Over temperature maximum the magnitude of the motor speed will be limited The speed limit is 3200 100 when the temperature is equal to the Over temperature minimum and it decreases linearly with temperature so that the speed limit is 0 when the temperature is equal to the Over temper
124. r are considered minimal safety requirements and the temporary limits cannot 6 Using the Serial Interface Page 73 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation be changed in a way that makes the controller less safe than this This means that the Maximum Speed Acceleration and Deceleration temporary limits cannot be increased beyond their hard limit counterparts and the Brake Duration limits cannot be decreased below their hard limit counterparts If you try to set a temporary limit in a way prohibited by the corresponding hard limit the temporary limit value is set to the hard limit and the response code byte indicates that the value could not be set as requested If the arguments to this command are valid the controller responds to this command with a single byte code Response Code Description 0 No problems setting the limit 1 Unable to set forward limit to the specified value because of Hard Motor Limit settings 2 Unable to set reverse limit to the specified value because of Hard Motor Limit settings 3 Unable to set forward and reverse limits to the specified value because of Hard Motor Limit settings Limit IDs above 11 and limit values outside of their allowed value ranges result in a Serial Format Error and no response is transmitted by the controller 3 The limit values set with this command persist only until the controller is next reset or the Apply settings button
125. r high current applications and place a large capacitor across power and ground near the motor controller to limit electrical noise such a capacitor is pre installed on fully assembled 18v7 18v15 and 24v12 controller versions 9 The Simple Motor Controllers feature a configurable low voltage shutoff that can help you avoid damaging batteries that are sensitive to over discharging such as Li Po packs See Section 5 for more information Motor Considerations The two terminals of your brushed DC motor connect to the OUTA and OUTB pins When selecting a motor for your controller or a controller version for your motor it is important to consider how the motor will be used in your system If the motor is likely to be stalled for prolonged periods of time or under heavy load or if the motor will be rapidly changing direction without acceleration limiting enabled you should be taking into 4 Connecting Your Motor Controller Page 30 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation account the stall current of the motor at the voltage it will be running and selecting a controller that can deliver a continuous current that exceeds the stall current 9 It is not unusual for the stall current of a motor to be an order of magnitude 10x higher than its free run current When a motor is supplied with full power from rest it briefly draws the full stall current and it draws nearly twice the stall curre
126. r or a PC Input Mode is Serial USB and the configurable time period has elapsed with no valid serial or USB commands being received by the controller The purpose of this error is to ensure that your motor will stop if the software talking to the controller crashes or if the communications link is broken All valid serial commands clear this error The native USB commands for setting the speed and exiting safe start also clear this error By default this error is disabled but it can be enabled from the Advanced Settings tab by setting a non zero Command Timeout value e Limit kill switch This error occurs when a limit or kill switch channel stops the motor More specifically it occurs in three cases when a kill switch is active when a Forward Limit switch is active AND the Target Speed is positive or when a Reverse Limit switch is active AND the Target Speed is negative A limit kill switch is considered active if its scaled value is above 50 If you are using a limit switch and your input mode is Serial USB you will need to check the Count column in the Status tab to see this error because in Serial USB mode the Target Speed gets set to 0 whenever there is an error e Low VIN This error occurs whenever your power supply s voltage is too low or it is disconnected If you set the correct thresholds in the Advanced Settings tab this error will prevent you from over discharging your battery e High VIN This error occurs whenever your pow
127. r than this reading so you should not rely on this temperature reading when deciding whether it is safe to touch the board e Up Time This is the total amount of time that the controller has been running since its last reset or power up The Up Time reading can be used to help identify if the controller has reset unexpectedly You can determine the cause of a reset by looking at the pattern of the yellow LED see Section 3 5 or you can look in the Device Information window available from the Device menu The Up Time reading will overflow back to zero after 49 7 days e Baud Rate This is the current baud rate that the device is using on the TTL serial interface RX and TX lines in units of bits per second bps By default the device is in Auto detect baud rate mode so this value will be N A until the baud rate is detected After a OxAA byte is received on the RX line the device will detect the baud rate and you can see it here Please note that the Baud Rate display in the Status tab has nothing to do with the USB virtual COM port it doesn t matter what baud rate you use when connecting to the virtual COM port e RC Period This is the period of the RC signal on the RC1 input channel You can use this reading to help you make the RC period settings in the Advanced Settings tab more strict so that the controller can better identify bad RC signals If the signal on RC1 is invalid this reading is reported as N A Manually set spee
128. r that drives the left motor as mixing mode left You can splice together your own cables or use premade Y splitter cables https www pololu com product 2164 to connect channels 1 and 2 from your RC receiver to channels and 2 of both controllers as shown in the diagram above You can also connect the ERR lines of both controllers together to ensure that both controllers stop if either controller experiences an error The following pictures show 4 Connecting Your Motor Controller Page 41 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation a Wild Thumper 4WD chassis https www pololu com product 1567 being driven by two Simple Motor Controllers in mixed RC mode as depicted in the above wiring diagram Limit Kkill Switches Unused RC channels can also be used as limit or kill switches For example you could use an RC signal as a kill switch to stop your autonomous serially controlled robot if it gets into trouble When configured as a limit or kill switch if the channel s value exceeds more than half of its forward value the switch is activated We recommend you use the Channel Setup Wizard click the Learn button in the Simple Motor Control Center for any RC channel you configure as a limit or kill switch 4 4 Connecting a Potentiometer or Analog Joystick Simple Motor Controller can be directly connected to a 0 to 3 3 V analog voltage source such as a potentiometer or ana
129. rested in receiving TTL serial bytes from the motor controller you can leave the TX line disconnected See Section 4 2 for more information on connecting a serial device to the Simple Motor Controller The serial interface is asynchronous meaning that the sender and receiver are separately configured ahead of time to agree on the length of a bit this is known as the baud rate and it is usually specified in bits per second or bps and each side independently times the serial bits The Simple Motor Controller has the ability to automatically detect the baud rate which means that it can be used even when the baud rate of the serial source is unknown as long as the serial source initiates communication by sending the proper baud rate indication byte OxAA written as 170 in decimal notation The Simple Motor Controller works with baud rates from 1200 to 500 000 bits per second Asynchronous TTL serial is available as hardware modules called UARTs on many microcontrollers but it can also be bit banged by a standard digital output line under software control The data format is 8 data bits no parity bit and one stop bit which is often expressed as 8 N 1 The diagram below depicts a typical asynchronous non inverted TTL serial byte LSB MSB 10011010 cc ov UU UU n om start bit stop bit Diagram of a non inverted TTL serial byte A non inverted TTL serial line has a default non active state of high A transmitted byt
130. rial and have disabled Safe Start the motor will start driving as soon when a valid Set Speed command is received These are the types of serial errors that are recorded o Frame This is error occurs when a de synchronization or excessive noise on the RX line is detected o Noise This error occurs when noise is detected on the RX line RX overrun This error occurs when the buffer for storing bytes received on the RX line is full and data was lost as a result This should not occur during normal operation 3 Getting Started Page 21 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Format This error occurs if the serial bytes received on RX or the virtual COM port do not obey the protocol specified in this guide If you get this error check the bytes you are sending carefully and compare them to the examples provided e CRC This error occurs if you have enabled cyclic redundancy check CRC for serial commands but the CRC byte received was invalid CRC helps prevent the motor controller from accidentally performing unwanted actions when it is receiving commands over a noisy serial link If you get this error check your algorithm for calculating CRCs and check the quality of your serial signal at the RX pin 3 5 LED Feedback The Simple Motor Controllers have three indicator LEDs that provide feedback about the current state of the controller The LEDs can tell you whether an error is occ
131. rial write 0x83 speed should be a number from 3200 to 3200 void setMotorSpeed int speed if speed lt 0 smcSerial write 0x86 motor reverse command speed speed make speed positive else smcSerial write 0x85 motor forward command smcSerial write speed amp 0x1F smcSerial write speed gt gt 5 void setup initialize software serial object with baud rate of 19 2 kbps smcSerial begin 19200 the Simple Motor Controller must be running for at least 1 ms before we try to send serial data so we delay here for 5 ms delay 5 if the Simple Motor Controller has automatic baud detection enabled we first need to send it the byte OxAA 170 in decimal so that it can learn the baud rate smcSerial write 0xAA send baud indicator byte next we need to send the Exit Safe Start command which clears the safe start violation and lets the motor run exitSafeStart clear the safe start violation and let the motor run void loop setMotorSpeed 3200 full speed forward delay 1000 setMotorSpeed 3200 full speed reverse delay 1000 Advanced Example This example assumes the following connections exist between the Arduino and the Simple Motor Controller e Arduino digital pin 3 to Simple Motor Controller TX e Arduino digital pin 4 to Simple Motor Controller RX e Arduino digital pin 5 to Simple Motor Controller RST e Arduin
132. roduct ID low product ID high minor FW version BCD major FW version BCD byte byte format format Description This command lets you read the Simple Motor Controller product number and firmware version number The first two bytes of the response are the low and high bytes of the product ID each Simple Motor Controller version has a unique product ID and the last two bytes of the response are the firmware minor and major version numbers in binary coded decimal BCD format http en wikipedia org wiki Binary coded_decimal BCD format means that the version number is the value you get when you write it in hex and then read it as if it were in decimal For example a minor version byte of 0x15 21 means a the minor version number is 15 not 21 Example To request the product ID and firmware version we would transmit the following compact protocol byte and wait until we have received four bytes in response from the Simple Motor Controller or until our receiving function times out which could happen if there is a problem We Send Command Byte Compact Protocol OxC2 194 We Receive Response Byte 1 Response Byte 2 Response Byte 1 Response Byte 2 0x98 152 0x00 0 0x00 0 0x01 1 This response tells us that the product ID is 0x0098 152 and the firmware version is 1 0 Stop Motor any input mode Command Format 6 Using the Serial Interface Page 75 of 108 Pololu Simple Motor Controller User s Guide 2001 2015
133. s seconds per 7 2e7 bits 65 536 ms These variables contain the user imposed limits on the motor output such as maximum speed acceleration and deceleration These variables are initialized to the hard motor limit settings see Section 5 2 every time the controller is powered up or reset and every time the apply settings button is pressed in the Simple Motor Control Center These temporary limits can be changed via the serial interface while the controller is running to impose stricter safer limits than the hard motor limit settings see the Set Motor Limit command in Section 6 2 1 and Section 6 3 1 6 Using the Serial Interface Page 89 of 108 Pololu Simple Motor Controller User s Guide bo 30 31 32 33 36 37 38 39 Name Max Speed Forward Max Acceleration Forward Max Deceleration Forward Brake Duration Forward Max Speed Reverse Max Acceleration Reverse Max Deceleration Reverse Brake Duration Reverse Type unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit unsigned 16 bit Description Maximum allowed motor speed in the forward direction 0 to 3200 Maximum allowed motor acceleration in the forward direction 0 to 3200 0 means no limit Maximum allowed motor deceleration from the forward direction 0 to 3200 0 means no limit Time spent braking at speed 0 when tran
134. s remember to wire the grounds together and ensure that each device is properly powered Unpowered devices with a TTL serial port can turn on or partially on drawing power from the serial line which means that extra care must be taken when turning power off and on to reset the devices Note You must use an inverter and level shifter such as a MAX232 or a Pololu 23201a Serial Adapter https www pololu com product 126 if you want to interface an RS 232 device with the Simple Motor Controller Connecting an RS 232 device directly to the Simple Motor Controller can permanently damage it 4 Connecting Your Motor Controller Page 35 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Serial Interface Pin Descriptions Pin Direction Description Simple Motor Controller TTL serial receive pin This should be connected to the TTL serial output transmit line of your other device This connection is only required if you want to send serial commands to the motor controller from your other device RX Input Simple Motor Controller TTL serial transmit pin This should be connected to TX Output the TTL serial input receive line of your other device This connection is only required if you want to receive serial feedback from the motor controller Simple Motor Controller active low reset pin This pin is internally pulled high driving it low resets the motor controller You must wait for at least 1 ms a
135. se bytes using the following equation variable_low_byte 256 variable_high_byte If the variable type is signed and the above result is greater than 32767 you will need to subtract 65536 from the result to obtain the correct signed value Alternatively if it is supported by the language you are using you can cast the result to a signed 16 bit data type Requesting variable IDs between 41 and 127 results in a Serial Format Error and the controller does not transmit a response Example To request the board temperature variable ID 24 we would transmit the following compact protocol bytes and wait until we have received two bytes in response from the Simple Motor Controller or until our receiving function times out which could happen if there is a problem 6 Using the Serial Interface Page 71 of 108 Pololu Simple Motor Controller User s Guide We Send Command Byte Data Byte 1 Compact Protocol OxA1 161 0x18 24 We Receive Response Byte 1 Response Byte 2 0x1E 30 0x01 1 This response tells us that the temperature is 30 256 1 286 in units of 0 1 C which means the board temperature is 28 6 C Set Motor Limit any input mode Command Format Command Data Byte Byte Data Byte 1 5 Compact o Protocol OxA2 162 limit ID limit byte 1 Pololu Protocol 0xAA 170 device 9499 84 number Response Format Response Byte 1 response code 2001 2015 Pololu Corporation Data B
136. sitioning from forward to reverse Maximum allowed motor speed in the reverse direction 0 to 3200 Maximum allowed motor acceleration in the reverse direction 0 to 3200 0 means no limit Maximum allowed motor deceleration from the reverse direction 0 to 3200 0 means no limit Time spent braking at speed 0 when transitioning from reverse to forward 2001 2015 Pololu Corporation Units internal units Aspeed per update period Aspeed per update period internal units Aspeed per update period Aspeed per update period 9 The Simple Motor Controller uses an internal system of units labeled internal units in the above tables where 3200 represents the maximum possible motor speed in the forward direction 0 represents a stopped motor and 3200 represents the maximum possible motor speed in the reverse direction The RC and analog channel inputs are scaled from their raw units into this internal 3200 to 3200 unit system using the channel calibration settings 6 5 Cyclic Redundancy Check CRC Error Detection For certain applications verifying the integrity of the data you are sending and receiving can be very important Because of this the Simple Motor Controller has optional 7 bit cyclic redundancy checking which is similar to a checksum but more robust as it can detect errors that would not affect a checksum such as an extra zero byte or bytes out of order Cyclic redundancy checking can be enab
137. stall Windows 7 8 and Vista or Continue Anyway Windows XP Would you like to install this device software Software Installation Name Pelolu USB AVR Programmer Drivers Pubbsher Poletu Corporation The software you are installing has not parsed Windows Logo testing to veely its compatiblity wath Windows XP Led me why thes testing is important Aweys trust software een Poloha Corporation Instat Deg Install You shouid only instal driver software from publinhers you trust How san decide inwing your installation of this software may impair nirsh dence saftnare n sate to natai Would you like to install this device software Name Polotu USB to Seriat Drivers egy Pbisher Poletu Corporation Abways trust software from Poloha Corporation instal Don t inital Vou should ordy ntal dewer software from publishers you trust How can ecg 4 After the installation is finished your start menu should have a shortcut to the Simple Motor Control Center in the Pololu folder This is a Windows application that allows you to configure control and get real time feedback from the Simple Motor Controller There will also be a command line utility called SmcCmd which you can run at a Command Prompt Windows 8 Windows 7 and Windows Vista users Your computer should now automatically install the necessary drivers when you connect a Simple Motor Controller No further action from you is required Windows XP
138. t Safe Start Serial USB input mode only Command Format GO lt CR gt Simple Motor Controller Hyper Terminal SEE Description This command clears the Serial USB safe start violation and allows the motor to run When Safe Start protection is enabled this command must be issued when the 152 01 00 controller is first powered up after any reset and after any error stops the 3200 motor t Motor Forward Serial USB input mode only Command Format F lt speed gt lt CR gt Description This command sets the motor target speed in the forward direction The argument speed can be an integer from 0 motor stopped to 3200 motor forward at full speed or an integer percentage from 0 to 100 You can represent the speed in hex by putting an H at the end of the number If the argument speed is outside the allowed range a Serial Format Error occurs Examples The following commands all make the motor drive forward at half speed e F1600 lt CR gt F50 lt CR gt o E640H lt CRY Connected 0 07 06 Auto detect 2400 8 N 1 Sending ASCII commands to the Simple Motor Controller Motor Reverse Serial USB input from HyperTerminal with echoing of typed characters mode only enabled Command Format R lt speed gt lt CR gt Description This command sets the motor target speed in the reverse direction It behaves the same as the Motor Forward command above except the m
139. t it can learn the baud rate command 0 OxAA sendBlocking command 1 send baud indicator byte next we need to send the Exit Safe Start command which clears the safe start violation and lets the motor run exitSafeStart clear the safe start violation and let the motor run program execution starts here int main setup while 1 loop forever setMotorSpeed 3200 delay ms 1000 setMotorSpeed 3200 delay _ms 1000 2001 2015 Pololu Corporation 6 Using the Serial Interface Page 99 of 108 Pololu Simple Motor Controller User s Guide Advanced Example 2001 2015 Pololu Corporation This example assumes the following connections exist between the Orangutan and the Simple Motor Controller e Orangutan pin PDO to Simple Motor Controller TX e Orangutan pin PD1 to Simple Motor Controller RX e Orangutan pin PCO to Simple Motor Controller RST e Orangutan pin PC1 to Simple Motor Controller ERR e Orangutan GND to Simple Motor Controller GND Pins PDO and PD1 are the Orangutan s hardware serial receive and transmit lines respectively and must be connected to the Simple Motor Controller as described above for this sample program to work There is nothing special about pins PCO and PC1 however you can connect any free digital pins to the Simple Motor Controller RST and ERR pins if you change the pin definitions at the top of the sample program accordingly See Section 4 2 f
140. tatus LED primarily gives feedback about the motor driver outputs e An even blinking pattern of on for 2 3 s and off for 2 3 s indicates that the controller is not driving the motor and has not yet detected the baud rate This pattern only occurs when the controller is in USB serial mode with automatic baud detection enabled and helps you determine when you have established communication between a TTL serial source and the Simple Motor Controller e A brief flash once per second indicates that the controller is not driving the motor If the controller is in Serial USB mode with automatic baud detection enabled this pattern additionally indicates that the Simple Motor Controller has successfully learned the TTL serial baud rate e A repeating gradual increase in brightness every second indicates that the controller is driving the motor forward e A repeating gradual decrease in brightness every second indicates that the controller is driving the motor in reverse 3 Getting Started Page 24 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 4 Connecting Your Motor Controller This chapter explains all the electrical connections you might need to make to get your motor controller working the way you want it to The diagrams below label the key components and pins on the Simple Motor Controllers Most of these pins are also labeled on the bottom side of the board Simple Motor Controller 18v7 Pin
141. tive analog power pins in order to detect whether your potentiometer is connected The analog channel will still be considered invalid if the voltage goes out of the acceptable range specified by the Error min and Error max parameters for that channel This option is necessary if you are connecting a limit switch or other device to the analog input in a way that prevents the disconnect detection from working The Never sleep ignore USB suspend option prevents the device from going in to deep sleep mode in order to comply with the suspend current requirements of the USB specifications Checking this option will make the device non USB compliant but will allow it to perform some functions while connected to a sleeping PC via USB and the VIN power supply is disconnected Note that the Simple Motor Controller can not drive a motor while VIN is disconnected The Command timeout error occurs if you are controlling your motor using a microcontroller or a PC Input Mode is Serial USB and the Command Timeout period has elapsed with no valid serial or USB commands being received by the controller The default value of Command Timeout is 0 which means the error is disabled The Command Timeout can be specified with 0 01 s resolution and can be as high as 655 35 s The purpose of the Command timeout error is to ensure that your motor will stop if the software talking to the controller crashes or if the communications link is broken For more details about this
142. to VIN Otherwise the USB 5V bus voltage replaces the output of the 5V regulator The 5V and 3 3V power buses are available via the RC BEC jumper pads see the upper right corners of the power connection diagrams above and a shorting block can be used to connect the RC power row to the desired voltage rail thereby powering a connected RC receiver with 3 3 or 5 V These pins can also be used to supply approximately 150 mA to other components in your system Trying Out the Controller with USB Once you have a connected a power supply and a motor you can use the Simple Motor Control Center to make the motor move and test how various settings affect the behavior of the motor see Section 5 for more information on configuring the Simple Motor Controller The Simple Motor Controller defaults to Serial USB input mode which lets you control the motor speed with the slider bar under the status tab If you have already changed the input mode of the device to something else you can restore it by going to the Input Settings tab selecting Serial USB as the Input Mode and clicking the Apply Settings button in the lower right corner F Pololu Simple Motor Control Center File Edit View Device Help Connected to 18v15 39FF 806 2054 3036 1128 0743 Status Input Settings Motor Setangs Advanced Settings 5 Motor Limts Conditions 7 38 Curent Speed 67 38 Baii f 2 Target Speed 73 25 VIN 124V Up Time 0 14 46 l ENDE SAE ee Tem
143. tocol or Mini SSC protocol should be used when multiple Pololu devices are receiving the same serial data This allows the devices to be individually addressed and it allows responses to be sent without collisions If the devices are configured to detect the baud rate then when you issue your first Pololu Protocol command the devices can automatically detect the baud from the initial OxAA byte Some older Pololu devices use 0x80 as an initial command byte If you want to chain these together with devices expecting OxAA you should first transmit the byte 0x80 so that these devices can automatically detect the baud rate and only then should you send the byte OxAA so that the Simple Motor Controller can detect the baud rate Once all devices have detected the baud rate Pololu devices that expect a leading command byte of 0x80 will ignore command packets that start with OxAA and Pololu devices that use the Pololu Protocol such as the Simple Motor Controller will ignore command packets that start with 0x80 6 Using the Serial Interface Page 93 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 6 7 Sample Code This section contains example code for controlling the Simple Motor Controller over TTL serial or over the USB virtual serial port These examples use the Compact Protocol without CRC error detection so they require the Simple Motor Controller to be in Binary serial mode with the CRC Mode set to Disa
144. tor The red LED is tied directly to the active high output ERR which allows the error status to be monitored by an external device such as a microcontroller When no errors are stopping the motor the error LED is off and the ERR pin is pulled low See Section 4 2 for more information about the ERR pin and the error LED Yellow Status LED This LED helps you visually identify the state of the device which can be useful when the controller is not connected to the Control Center On start up the status LED briefly flashes a pattern indicating the source of the last reset see the Reset Flags variable in Section 6 4 for more information e 8 blinks over the first two seconds after start up indicates that the external RST pin was driven low to reset the controller e 3 blinks over the first two seconds after start up indicates that the controller last reset because logic power got too low power was disconnected or the controller browned out e Rapid flickering for the first two seconds after start up indicates that the controller was reset by a software fault or by a firmware upgrade This startup behavior can help you detect if your Simple Motor Controller is browning out and resetting unexpectedly as can happen if your input voltage drops due to high power demands or electrical noise 3 Getting Started Page 23 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation After the start up phase ends the s
145. tor Simple High Power Motor Simple High Power Motor Controller 18v15 or 24v1i2 Controller 18v15 or 24v12 Controller 18v15 or 24v1i2 partial kit with included fully assembled partial kit with custom hardware power and motor connectors NOT included The medium power controller versions 18v15 and 24v12 are available with the power capacitor and connectors included but not soldered in as shown in the left picture above or with the power capacitor and connectors pre installed as shown in the middle picture above The terminal blocks are only rated for 15 A For higher current applications we recommend soldering thick wires directly to the connector free version of the board and using higher current connectors 1 Overview Page 7 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation https www pololu com product 925 as shown in the right picture above Another benefit of the connector free version is flexibility in placement of the power capacitor e g on the other side of the board to accommodate compact installations or to make room for a heat sink The power capacitor has a significant effect on performance the included capacitor is the minimum size recommended and bigger ones can be added if there is space A bigger capacitor might be required if the power supply is poor or far more than about a foot from the controller 1 90 0 086 Pololu umcdja 2010 0 322790 rc Pololu High
146. u Corporation 6 7 4 Windows C Example For example C code that shows how to control a Simple Motor Controller using its serial interface in Microsoft Windows download SmcSerialCWindows zip https www pololu com file download SmcSerialC Windows zip file_id 0J558 5k zip This zip archive contains a Microsoft Visual C 2010 Express project and the provided C code can also be compiled with MinGW This example is like the previous example except it does the serial communication Windows specific functions like CreateFile and WriteFile 9 For this example to work the Simple Motor Controller s input mode must be Serial USB the serial mode must be Binary and the CRC Mode must be set to Disabled These are the default settings that the controller is shipped with The controller should be connected to the computer via USB 6 7 5 Bash Script Example The Bash shell script below works on Linux and Mac OS X 10 7 or later It demonstrates how to control a Simple Motor Controller over USB You can run it using the example commands given below You will need to change the DEVICE argument to be the name of the Simple Motor Controller s virtual serial port see Section 6 9 For this script to work the Simple Motor Controller s input mode must be Serial USB the serial mode must be Binary and the CRC Mode must be set to Disabled These are the default settings that the controller is shipped with The controller should be connected to the computer
147. urring whether the USB connection is active what direction the motor is driving and much more ge i5 see a i te gt a sa LE ems G r Simple High Power Motor Controller 18v15 or 24v12 LEDs 3 Getting Started Page 22 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Q an e 88 eeee Simple High Power Motor Controller 18v25 or 24v23 LEDs The Simple Motor Controllers have three indicator LEDs Green USB LED This LED indicates the USB status of the device When the Simple Motor Controller is not connected to a computer via the USB cable the green LED will always be off When you connect the controller to USB the green LED starts blinking slowly The blinking continues until the controller receives a particular message from the computer indicating that the Simple Motor Controller s USB drivers are installed correctly see Section 3 1 for driver installation instructions After the controller gets this message the green LED turns solidly on except for brief flickers whenever there is USB activity The Simple Motor Control Center software constantly streams data from the controller so when the control center is running and connected to the Simple Motor Controller the green LED will flicker constantly Red Error LED This LED turns on whenever there is an error stopping the motor see Section 3 4 for information on errors that can stop the mo
148. users Follow steps 5 9 for each new Simple Motor Controller you connect to your computer 5 Connect the device to your computer s USB port The Simple Motor Controller shows up as two devices in one so your XP computer will detect both of those new devices and display the Found New Hardware Wizard two times Each time the Found New Hardware Wizard pops up follow steps 6 9 3 Getting Started Page 11 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 6 When the Found New Hardware Wizard is displayed select No not this time and click Next Found New Hardware Wizard Welcome to the Found New Hardware Wizard Windows will search for current and updated software by looking on your computer on the hardware installation CD or on the Windows Update Web site with your permission Read our privacy policy Can Windows connect to Windows Update to search for software O Yes this time only Yes now and every time connect a device No not this time Click Next to continue 7 On the second screen of the Found New Hardware Wizard select Install the software automatically and click Next 3 Getting Started Page 12 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Found New Hardware Wizard This wizard helps you install software for Pololu Simple High Power Motor Controller 18 15 C
149. ust calling the library function appropriate for your Orangutan board void setBaudRate unsigned long baud if SERIAL PORTS gt 1 serial set _baud_rate UARTO baud else serial set baud rate baud endif a void sendBlocking char buffer if _SERIAL PORTS gt 1 serial _send_blocking UARTO buffer size else serial send blocking buffer size Orangutan X2 and SVP users unsigned char size Orangutan X2 and SVP users 6 Using the Serial Interface Page 100 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation endif char receiveBlocking char buffer unsigned char size unsigned int timeout_ms if SERIAL PORTS gt 1 Orangutan X2 and SVP users return serial receive blocking UARTO buffer size timeout_ms else return serial_receive blocking buffer size timeout_ms endif required to allow motors to move must be called when controller restarts and after any error void exitSafeStart command 0 0x83 sendBlocking command 1 speed should be a number from 3200 to 3200 void setMotorSpeed int speed if speed lt 0 command 0 0x86 motor reverse command speed speed make speed positive else command 0 0x85 motor forward command command 1 speed amp OxlF command 2 speed gt gt 5 sendBlocking command 3 char setMotorLimit unsigned char limitID unsigned
150. utton in the Simple Motor Control Center for any analog channel you configure as a limit or kill switch 4 Connecting Your Motor Controller Page 45 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Normally open NO switches can also be used as limit kill switches with this controller but they are not as safe since accidental disconnection will lock the switch in an inactive state 4 Connecting Your Motor Controller Page 46 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 5 Configuring Your Motor Controller The Simple Motor Controllers can be configured over USB using the Pololu Simple Motor Control Center which is available for download from the Pololu website see Section 3 1 5 1 Input Settings The Input Settings tab of the Pololu Simple Motor Control Center allows you to quickly specify how you want to control the speed of the motor and also allows you to set up limit and kill switches As a first step we recommend that you click Quick Input Setup This will launch the Quick Input Setup Wizard which will let you specify how you want to control of the motor and if you are using analog or RC lets you quickly calibrate your inputs When you finish the Quick Input Setup Wizard your new settings will get saved in the Input Settings tab and will optionally be applied to the device so you can start using your new settings right away After
151. values for the second speed data byte are 0 100 so you can ignore the first speed data byte always set it to 0 and consider the second data byte to simply be the speed percentage For example to drive the motor at 53 speed you would use byte1 0 and byte2 53 Motor Reverse Serial USB input mode only Command Format Command Data Byte Data Byte Data Byte Byte Data Byte 1 2 3 4 Compact Protocol 0x86 134 speed byte 1 i bye Compact Alternate 0x86 134 0 speedo p g Use Pololu Protocol 0xAA 170 device gogio PDE speed byte number 1 2 device Pololu Alternate Use OxAA 170 0x06 6 0 speed number Description This command lets you set the full resolution motor target speed in the reverse direction The motor speed must be a number from 0 motor stopped to 3200 motor reverse at full speed and is specified using two data bytes the first containing the low five bits of the speed and the second containing the high seven bits of the speed This command behaves the same as the Motor Forward command except the motor moves in the opposite direction Motor Forward 7 Bit Serial USB input mode only Command Format Command Byte Data Byte1 Data Byte 2 Data Byte 3 Compact Protocol 0x89 137 speed Pololu Protocol OxAA 170 device number 0x09 9 speed 6 Using the Serial Interface Page 69 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation Description This com
152. ven invalid ones cause the Simple Motor Controller to respond when a termination character is received Using a Terminal Program ASCII mode makes it easy to communicate with the Simple Motor Controller from a terminal program such as HyperTerminal The responses are formatted so that they will appear nicely in the terminal window Simple Motor Controller Hyper Terminal SEE File Edit view Call Transfer Help Dawe 3 De eB y 1152 01 00 f3200 Connected 0 00 02 Auto detect 2400 8 N 1 We recommend you enable local echoing of transmitted characters when typing commands into a terminal program The following picture shows our recommended ASCII settings when using HyperTerminal 6 Using the Serial Interface Page 78 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation ASCII Setup ASCII Sending Send line ends with line feeds Echo typed characters locally Line delay 0 f milliseconds Character delay 0 milliseconds ASCII Receiving C Append line feeds to incoming line ends C Force incoming data to 7 bit ASCII Wrap lines that exceed terminal width j Cancel You can get to this dialog by going to the File gt Properties menu and clicking on the ASCII Setup button under the Settings tab 6 Using the Serial Interface Page 79 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation 6 3 1 ASCII Command Reference Exi
153. ximum speed limits starting speed limits and gradual temperature based speed limiting If any of these things are affecting the Current Speed the appropriate part of the Status tab will be highlighted to let you know Anything that is stopping the motor completely will be highlighted in red Anything that is limiting the speed of the motor will be highlighted in yellow The Simple Motor Controller represents speeds internally as a number from 3200 full reverse to 3200 full forward However by default the speeds in the Status Tab are displayed as percentages so 3200 full reverse is shown as 100 00 and 3200 full forward is shown as 100 00 Below the Target Speed label is a two dimensional diagram that represents the values of the inputs that are used to set the Target Speed This diagram is especially useful in RC or Analog mode with Mixing enabled because 3 Getting Started Page 17 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation it graphically shows you the value of both input channels and makes it easier to tell how well the Simple Motor Controller is calibrated for your controller is Motor Limits The Motor Limits box in the Status tab shows the current limits on the movement of the motor These limits will be equal to the hard motor limits specified in the Motor Settings tab unless you have temporarily changed the motor limits using the command line utility SmcCmd or a serial command
154. you the most information including a Serial a 89 running count of how many times the error has been reported Frame 2 e Running the command line utility p just type smccmd s at the command RX overrun E line Format Looking at the red LED on the device CRC 7 It will be lit if there are any errors Reset Counts ines stopping your motor Writing PC software or using a The Errors box in the Status tab of the Pololu Simple microcontroller to send the Get Errors Motor Control Center reveals problems that are stopping serial command your motor e Using a microcontroller to measure the voltage on ERR pin This pin is linked to the red LED so it should go high 3 3 V when there is an error stopping your motor and low 0 V otherwise All the errors are explained below e Safe start violation Safe Start is a feature that helps prevent the motor from starting up unexpectedly This feature is enabled by default but can be disabled in the Advanced Settings tab The behavior of Safe Start depends on what Input Mode you are using In Serial USB input mode the Safe start violation error occurs whenever any other error is stopping the motor After all the other errors have been fixed you can clear the Safe start violation error by pressing the Resume button which issues a native USB command or using a serial command In Analog or RC input mode the Safe start violation error occurs whenever the motor is stopped because of an error
155. yte Data Byte Data Byte 3 4 5 limit byte 2 z limit ID limit byte 1 limit byte 2 Description This command lets you change the temporary motor limit variables documented in Section 6 4 The ID of the limit to set is specified by the first compact protocol data byte and the value of the limit is specified by the next two data bytes the first of which limit byte 1 contains the low seven bits of the value and the second limit byte 2 contains the high seven bits Limit IDs from 0 to 3 are affect both forward and reverse limits equally they are symmetric Limit IDs from 4 to 7 affect only forward limits and limit IDs from 8 to 11 affect only reverse limits The following table provides the limit IDs for all of the temporary motor limit variables along with the allowed limit values 6 Using the Serial Interface Page 72 of 108 Pololu Simple Motor Controller User s Guide 2001 2015 Pololu Corporation ID Name Allowed Values Units 0or4 Max Speed Forward 0 3200 0 0 3200 100 lor5 Max Acceleration Forward 0 3200 0 no limit ee Per update period 2 or 6 Max Deceleration Forward 0 3200 0 no limit er eke Per update period 3o0r7 Brake Duration Forward 0 16384 4 ms 0 or 8 Max Speed Reverse 0 3200 0 0 3200 100 lor9 Max Acceleration Reverse 0 3200 0 no limit Aspeed per update period 2 or 10 Max Deceleration Reverse 0 3200 0 no limit ae per update period 30r 11 Brake Duration Reverse

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