Technical Questions (PCD Series)
Contents
1. Bi directional pulse output The PO terminal outputs CW pulses for rotating in the positive direction The PO terminal outputs CCW pulses for rotating in the negative direction Common pulse output also referred to as a one pulse output For rotating in either direction the PO terminal outputs the drive pulses and the PO terminal outputs a HIGH or LOW to signal the direction of rotation gt When bit DO PO output logic setting is 0 negative logic if the PO signal is HIGH the motor will rotate in the positive direction and when it is LOW it will rotate in the negative direction With the PCD4541 you can select between bi directional pulses and common pulses using register R7 The PCD4511 and PCD4521 do not have this choice and only bi directional pulse output is available If you want to use common pulses with these models you will have to add a gate circuit one IC will be enough The PCL series has this choice for all of the models in that series The type of input pulse required by a motor driver varies with each manufacturer Looking at the commercially available drivers board types and box types most are the bi directional pulse type and the drive ICs are mostly the command pulse type Some board type and box type drivers have a function for selecting a pulse output type with a dip switch Do we need to match the reference clock CLK with the clock frequency for the CPU that is accessing the PCD No there is no2. What are idling pulses in concrete terms Stepper motors cannot self start if the maximum self start frequency is exceeded and they may not rotate normally This is called being out of step When the PCD is triggered to start an acceleration it starts sending pulses right after the trigger Even with the first pulse output the speed calculated from output pulse frequency may be faster than the motor s FL speed because the cycle is so short This means that the stepper motor may be out of step even at an FL speed that should otherwise be possible with a self start made from the calculated value So in order to start at self start speed there is a way to delay the acceleration that normally occurs right after the start command This allows the motor to move at FL speed for a few pulses and then start accelerating These few pulses that allow it to move at FL speed are referred to as idling pulses In order to accelerate to FH speed in the shortest possible time the FL speed should be set near the upper limit of self starting speed for the motor However if the idling pulses are set to 0 the initial speed will quickly rise above the set value So the FL speed must be set lower than the upper limit Another point to consider is that when idling pulses are used when the acceleration has started the motor has rotational torque which means that the acceleration speed can be set higher In order to reduce the feed time for a positi
3. Regardless of the stop factor the PCD makes sure that the last pulse is a full length pulse Then it stops the motor Therefore when checking the clock status after an error stop occurs it might be LOW In this case the chip will reset PO to HIGH After setting bit 0 and 1 in the control mode command to 00 disable the ORG and SD signals if one of these sensors turns ON goes LOW do the ORG SD signals monitored status 1 change to 1 ON status The status always reflects the condition of the physical terminal Even if the ORG SD signals are disabled 0 with the control mode command if the terminals go LOW level the status of these signals will be ON 1 In preset operation even though the preset countdown counter is set to 0 stop the status does not change to stopping Why What are the conditions in which this will become 0 Basically when stopped the status should be stopping Possible causes 1 The operation status monitor is bit 3 in status 0 A1 0 AO 0 Are you reading a different status a different address 2 Is FL or FH speed register value 0 0 is not allowed for the FL or FH speed However if FL speed 0 FH speed 0 for the preset operation in an FH constant speed start the last pulse may not be returned to HIGH That is it could stay LOW The operation status monitor does not change to stopping 0 until the last pulse becomes HIGH To check this monitor the following e Inaconstant speed prese
4. D When the motor is decelerated to a new FH speed that is a lower value than the current FH speed and if the FH speed is changed again the motor will accelerate or decelerate to this new FH speed However if the FH speed is changed after the motor starts deceleration from a ramp down point it will not change back to the new FH speed Instead it will decelerate to the FL speed and stop The conditions needed to decelerate to the FL speed from the FH speed in preset operation are Preset counter residual pulses lt Ramp down point setting As long as this condition is established the motor will move toward the FL speed If the FL speed is changed to a higher speed the motor will accelerate to the new FL speed and stop If the ramp down point setting is changed to 0 the conditions above will not be established and the motor will accelerate to the new FL speed In any case the motor will stop when the preset counter R0 goes to 0 We are using the PCD series If we change the preset amount RO during a preset operation does the PCD generate any positional deviation We recommend the following measures 1 Set bit 3 in the register select command to 1 2 Change the RO amount 3 Return bit 3 in the register select command to 0 Restrictions Due to the CPU processing time the total number of pulses may deviate somewhat there may be some excess pulses If the CPU you are using is faster and if the RO is changed ju
5. need to match frequency of the PCD to the CPU
6. program your desired operation D We want to use the PCD45xx as a simple oscillator whose frequency can be changed easily We don t want to use the ramp down point In this application is the maximum output frequency 400 kpps We specify a maximum frequency of 400 kpps in the general specifications for the PCD series taking into account the number of bits in the registers used for the ramp down point setting and the acceleration deceleration rate setting However if you will simply be using it as an oscillator you may use a higher frequency Using the PCD series I want to place a number of pulses in RO at position a using the preset mode and start the motor While operating I want to write the preset amount b at position B then write amount c at position C As above we want to change preset amount during operation and finally I want to stop at position d positioning Can I do this For a PCD 1 Set the register select command bit 3 to 1 and temporarily stop the preset counter 2 Change the RO value 3 Return the register select command bit 3 to 0 However these steps have disadvantages As the PCD series was developed to put a priority on low cost they did not consider changing the target position while operating Even using the steps above the total number of pulses may deviate could become larger due to CPU processing time If the CPU processing speed is high perform these steps soon after status 3 bit 7 ch
7. trapezoid We want to use a 30 kpps frequency Is it possible It will be possible if you select the 4x mode for the multiplication rate Set R4 multiplication register to 150 If the reference clock is 4 9152MHz and ifthe maximum value of the speed register range is 8191 the maximum output frequency in 4x mode will be 8191 x 150 32764pps By increasing the multiplication rate it can output several hundred kpps Compared with the PCL series the PCD series has a smaller limit for the following settings e The number of bits in the acceleration deceleration rate register e The number of bits in the ramp down point setting register Therefore when the FH speed is high or you want to use a long acceleration time the PCD series may not be able to handle the necessary numbers If the ORG signal is input during preset operation what will the RO register value be ORG stop during preset operation Make bit 1 1 enable ORG signal in the control mode command and the PCL will stop operation when an ORG signal is input even it is operating with the preset command After stopping the RO value will be the number of residual pulses Page 41 in the PCD4511 4521 4541 user s manual says RO subtracts one count for each pulse that is output If the R4 multiplication register is changed how will the RO counter behave For RO counter and R7 setting the R4 multiplication register changes the multiplication rate of the frequency and
8. Technical Questions PCD Series Chips The motor will turn in a CW direction but it does not turn in a CCW direction What are some possible causes for this Check the following 1 Is an EL signal being input 2 Is specification of the direction appropriate 3 Is the selection of output method 2 pulse mode or common pulse direction signal mode appropriate for the driver When 0 is put in the preset counter will there be any problem with the operation of the PCL When you specify 0 in the preset counter and write a start command the LSI will not operate in preset mode However there will not be any problem with its operation Can we write data to the PCD PCL even when the reference clock is stopped The PCD PCL cannot read or write data when the reference clock is stopped How should unused terminals be handled Unused terminals should be handled as follows 1 Input group active low terminals with a bar over the terminal name should be connected to a 5V terminal 2 Input group active high terminals without a bar over the terminal name should be connected to a GND terminal 3 Output terminals should be left open This does not apply to input terminals connected to a CPU such as DO to D7 RD WR CS A1 and A0 For details see the PDF file called How to handle unused terminals When the motor is stopped by turning ON the EL signal how do you release the EL signal In order to release the EL feed the motor in the
9. al or the ORG signal and not make an immediate stop The PCD only decelerates and does not stop when using the STP and ORG signals The SD signal only decelerates and does not stop the motor Therefore there is no other way to decelerate and stop than to use these commands with the PCD series The PCL60xx 61xx series can decelerate and stop using the STP signal In the PCD4511 4521 4541 manual an example of how to use the SD signal input is described What if we do not use the SD signal input If the SD signal is not input in the high speed zero return operation the motor will stop immediately at the FH speed when the ORG goes ON The motor may overrun a little due to inertia After the SD is ON if it turns OFF again before the ORG goes ON the motor will accelerate again to FH speed If we try to perform a zero return with a constant speed what will the operation be like If the motor executes a zero return with an FL constant speed start command the motor may not change operation regardless of whether the SD signal turns ON When operating at FL speed the motor stops when the ORG signal goes ON When the motor is executing a zero return from an FH constant speed command the motor will decelerate from FH speed to FL speed when the SD signal turns ON and stop when the ORG signal turns ON If the SD signal is not input the motor stops immediately when the ORG signal turns ON while at FH speed It may overrun a little as describe
10. anges from 1 to 0 so that the position won t deviate The result may vary with the frequency and the CPU processing speed For the PCL60xx 61xx series These models have a position override function Using this function the target position can be changed to a longer distance than the current position or to a position that has already been passed For details see the user s manual In preset operation I want to change speeds while operating To change the speed an operator shifts a joystick manually 6 stages so there are no fixed points for changing speed If the operator shifts the joystick while the motor is decelerating from a ramp down point the motor should not change speed and should be forced to decelerate to FL speed and stop at the preset amount Are these settings possible Try the following procedures and conditions 1 Select an FL speed and five FH speeds 2 Specify separate ramp down points for each of these five speeds 3 The acceleration deceleration rate must be constant during operation If operated at constant speed changes in the acceleration deceleration rate are possible However there will be a large number of ramp down points Write the program so that when the joystick lever is not shifted the motor will operate at FL speed 5 Determine with which speed the motor will operate at for each joystick position Then make a program that allows writing any of the five FH speeds into the FH speed register
11. ation deceleration operation in the middle to 1 in the output mode command When bit 3 in the output mode command is 0 the PCD will execute a normal ramp up down If it is set to 1 1 The PCL will halt a ramp up down the instant that the bit is set to 1 and it will hold the current pulse frequency 2 Ifthe PCD has stopped outputting pulses even if an FH high speed command is written it will feed at FL speed without a ramp up To determine the acceleration deceleration rate when the multiplication rate is set to 2x should we multiply the R1 R2 value by 2 Regardless of the multiplication rate the acceleration deceleration rates can be calculated using the following formulas Enter the same R1 R2 values as are set in each register For linear acceleration deceleration R3 Acceleration deceleration time x Reference clock frequency R2 R1 For S curve acceleration deceleration R3 Acceleration deceleration time x Reference clock frequency R2 R1 2 When relationship of the values in registers R1 FL and R2 FH is R1 gt R2 what will the operation be like The PCD PCL series changes the speed from FL to FH speed Therefore when R1 gt R2 it will decelerate from FL to FH speed If it is currently operating at FH speed it will accelerate from FH to FL speed In preset operation when the LSI reaches the ramp down point while feeding at FH speed it will accelerate to FL speed Therefore the shape will be an inverted
12. d in item 1 above Turning ON the SD signal means change speed from FH to FL using the current acceleration deceleration rates If FH lt FL the motor will accelerate to the FL speed when the SD signal is turned ON The SD signal can be monitored on the ST terminal monitor bit in the Status 1 register If you do not use the SD signal this terminal status can be checked in the status register so the ST terminal can be used as general purpose input terminal However D1 in the control mode must be set to 0 disabled On the PCD4541 we will use only three axes Should the terminals for the 4th axis be left open or should they be pulled up to VDD If there are some terminals that can be left open and if we leave them open how much power would be saved These terminals have an internal pull up resistor for protection However the resistance varies between 25 and 500 k ohms Even if they are left open the voltage level will probably be stable However to provide noise immunity we recommend pulling them up to VDD or shorting them together Terminals in question STA STP ORG EL EL SD SD U B F H There is no difference in the power consumption between leaving the input terminals open pulling them up to VDD or shorting them When you pull them down to GND the current consumption will increase by 0 09 mA to 1 8 mA per terminal We are currently designing a circuit using the PCD4511 This IC has only a 2 pulse output mode T
13. does not affect the number of pulses Therefore regardless of the setting in R7 the RO value will count down once for each pulse that is output How do we calculate the number of pulses needed for acceleration deceleration Can we obtain the number of pulses needed from the register values such as the acceleration deceleration rates In the PCD series both the acceleration and deceleration rates are equal which means that the number of pulses used for acceleration is equal to the number of pulses used for deceleration Calculate the value from the register values as follows CLK Reference clock frequency Hz R1 FL speed setting FL FL speed frequency pps R2 FH speed setting FH FH speed frequency pps R3 Acceleration deceleration rate Tsud Acceleration or deceleration time R4 Multiplication rate setting Psud Number of pulses needed for Acceleration or deceleration 1 In the case of linear acceleration deceleration Tsud R2 R1 x R3 CLK FL R1 x CLK 8192 x R4 FH R2 x CLK 8192 x R4 Psud FL FH x Tsud 2 2 In the case of S curve acceleration deceleration Tsud R2 R1 x R3 x 2 CLK FL R1 x CLK 8192 x R4 FH R2 x CLK 8192 x R4 Psud FL FH x Tsud 2 The acceleration and deceleration rates are the same in the PCD series Can this rate be changed after acceleration in order to use a different rate for deceleration It is possible to change the accele
14. e in item 1 above the I O elements may be damaged by latching up Be careful not to allow abnormal electrical noise to be applied to the LSI terminals When abnormal electrical noise is imposed on the LSI the symptoms will depend upon the energy level of the noise Lower levels of noise may only cause a malfunction Higher levels of noise may damage the elements Secure any unused input terminals to VDD or GND If the unused terminals are not held at VDD or GND since most of the terminals are pulled up or down internally significant problems may not occur However their ability to resist damage from electrical noise may drop significantly if they are left open The output terminals should never be shorted Protect the LSI from inductance produced by high voltage circuits and static electricity Use a design that protects the LSI against overvoltage due to noise power surges or static electricity Although the PCD4541 has a sequence circuit to drive a stepper motor we will not be using it We would like to supply normal pulse trains to a driver using a pulse generator to drive a motor Bi directional pulses and common pulse output are shown as the pulse types available What are these Are there any restrictions You can select the pulse output type bi directional common to match the motor driver you are using You will determine the rotation direction of the motor using bit D3 operation direction control in the control mode command
15. e won t be any problem in operating with such a number When the preset counter becomes 0 how will the counter value change Does it count 0 gt 1 gt 2 or 0 gt FFFFFF gt FFFFFE gt In continuous operation when the preset counter reaches 0 it changes as follows 0 gt FFFFFF gt FFFFFE gt When writing registers in the PCD series aside from RO all the registers are either 1 or 2 bytes Do we need to write Os in bits 16 to 23 No you do not need to write any value in bits 16 to 23 for 1 or 2 byte registers We want to connect to a Z80 CPU 8 MHz Is this possible It is possible A block diagram for the Z80 interface is shown on page 14 of the user s manual for PCD4511 4521 4541 Can the PCD output the INT signal when starting to ramp down in preset operation Set bit 4 ramp down point INT output control in the register to 1 The PCD will output the INT signal when starting to ramp down Reading bit 1 in the status 0 register lets you monitor this operation What can cause the PCD to output an INT signal The INT signal can be output when the PCD stops stop in preset operation by a change in the EL STP ORG signals or when stopped by the stop command or when starting to ramp down See page 32 Start mode command bit 5 and page 37 bits in the register select command in the user s manual for PCD4511 4521 4541 Even though I started the PCL in the preset mode and enabled the ORG signal wit
16. eate a pulse output and then use the OTS terminal for a direction signal Using an OR circuit with only one element makes the circuit simple In addition since the operation direction bit and the OTS bit are next to each other you can make a circuit that changes both bits at the same time so that the problems of the SD and EL terminals will be eliminated We want to perform repeat feed operations using the same start position but the end position is different for each feed A sensor turns ON to indicate the end point position Please tell us how to set up the PCD 1 Set bit 3 preset counter operation control in the Register Select command to 0 count output pulses 2 Set bit 2 preset operation control in the Control Mode Selection register to 0 continuous operation and set bit 3 to 0 positive direction 3 Start the PCD by writing a Start Mode command In order to stop the motor immediately when the sensor turns ON it is better to operate without using acceleration deceleration We recommend an FL constant speed start 4 When the sensor turns ON and the motor stops the PCD reads the RO preset amount register value and obtains the number of pulses that have been output from the start point 5 Set bit 2 in the Control Mode Selection register to 1 preset operation and set bit 3 to 1 negative direction Put the value read back into RO and start the motor using any of the start commands 7 Repeat the procedure above to
17. f1 to f4 are LOW the excitation signals will not turn off When using only PO output terminals should we mask the excitation signal output set output mode command bit 2 1 Or should we set them as outputs and leave them open as unused terminals If you do not use the excitation sequence you may mask the signals or not as you like However these are output terminals so they must be left open regardless of whether or not you mask the signals As the voltage only varies on the terminal it is not possible to be the cause of noise All of the PCD series models except for the PCD4541 have a two pulse output system for PO PO We would like to connect a one pulse type driver to a PCD series model that is not the PCD4541 It seems that we need to add a gate circuit to convert the two pulse signals to one pulse signals But we are considering always outputting a positive direction pulse through PO terminal and providing an external direction signal in order to change direction In this case what kinds of problem might occur You might have the following problems 1 Even if you attempt to drive the motor in the negative direction the PCD believes it is driving in the positive direction Therefore the SD signal and EL signal are disabled 2 When you read the control mode command the motor is always treated as moving in a positive direction One method to do this is to connect an external circuit that ORs the PO outputs to cr
18. gh speed start command for the same direction as the current operation the PCL changes to the new speed with acceleration So what happens when the start command is for the opposite direction Does the PCL pass through the 0 speed level and execute a linear or S curve acceleration in the opposite direction Or is the absolute value of the set speed applied and the PCL accelerates as usual Or does something else happen The R2 value is the speed figure Therefore to change the direction of operation you have to set bit 3 in the control mode command When this bit is toggled if the PCL is outputting pulses from the PO terminal starting from the next pulse it will output pulses from the PO terminal Therefore if this bit is changed during operation the motor will rotate in the opposite direction without any acceleration deceleration If you want to output pulses in the opposite direction using acceleration deceleration you should decelerate and stop Then change this bit and start at high speed In preset operation with acceleration deceleration we set the feed amount initial speed high speed and acceleration deceleration times for each register Why do we have to set the ramp down point separately in order to decelerate and stop The PCD series and PCL61xx series control the operation by the number of pulses not by the time and speed Therefore they need to be told start the deceleration when there are a specific number of residual pulse
19. h the control command when the ORG signal is input will the motor stop Is the INT output in this case After enabling the ORG signal if the ORG signal is input even in preset mode the motor will stop immediately Make bit 5 1 output INT when stopped in the start mode command and start the PCL It will output an INT signal when stopped by the ORG signal We are inputting an EL signal as a pulse Can we check this input in the status register The status register does not control the stop sequence It simply reads the EL EL terminals Therefore when only the EL signal is LOW bit 0 or bit 1 in status 1 will go ON Is it possible to read the status information while operating a motor If it is possible what stage does the status data come from It is possible to monitor the status information during motor operation The read status will be the status at the moment that the PCD takes its reading Can we monitor EL SD and ORG on a real time basis Are they the status information when the CPU reads from the sensor The current status of the sensors will be reflected in the status information when read We are using 4 pole excitation output to drive a motor In order to feed the pulse signals back to the CPU we are also using PO negative logic In a normal deceleration stop if the motor is stopped by a factor such as an EL signal or an immediate stop command and if PO is occasionally LOW will the chip return PO to HIGH
20. he driver we will use is a single pulse type Therefore we will OR the 2 pulses from the IC and use the OTS output as a direction switching output Is there any problem with this method Please be careful about doing this EL EL SD SD are available for use as machine sensor inputs Among these only the signals to the PCD4511 for the correct direction are effective For example when the PCD is operating in a negative direction if the positive direction signal is output with the OTS signal the PCD will operate in a positive direction In this case SD ED signals become invalid and this can be dangerous Specifically you must match the PCD operation direction to the OTS control On page 40 in the PCD4511 4521 4541 manual there is a description of how to mask the excitation output In this description there is a sentence can be used to turn off the excitation for a unipolar drive How about bipolar signals If f1 to f4 are LOW is the excitation turned off for bipolar signals From the sequence table on page 21 when 2 2 phase excitation is used column 3 shows all the phases LOW Is this condition related to turning off the excitation output The current flow direction changes according to the levels of f1 f2 In addition when f3 f4 are HIGH the current will not flow Although it would be convenient if only by selecting the bipolar mode f3 phase4 would become HIGH when setting the mask the PCL was not designed this way Therefore even if
21. int was true at the beginning and the rampdown point INT output was enabled Then the PCD will output an INT the next time the conditions are met For example if rampdown point 0 preset 0 the rampdown point INT output is enabled in the register select command and continuous operation is started FFFFFFh gt FFFFFEh gt gt 1 gt 0 The counter will function as shown above When it reaches 0 the PCD will output an INT signal With the settings you described the PCD should output the INT signal It may be that the setting was changed Please read the R5 data using the extension monitor function when the motor is stopped and see if the values you set have been changed It is better to check the details using the register select command However when you try to read the extension monitor you have to write a register select command This means that you would have to be able to read out what you just wrote as the register select command and unfortunately the PCD does not have a function for reading register select commands you have already set Therefore please store the values you use in memory when using an application program to write the register select command We put a value in the preset counter perform an operation and stop Then we want to know the cause of the stop whether it was caused by using all the pulses or by the EL signal or by both Is there any method for evaluating the cause of a stop other than by looki
22. n this case if the rampdown point R5 0 will the motor stop at the RO 0 position and output an INT signal Yes By setting bit 4 1 output an INT at the rampdown point in the register select command if R5 gt RO the LSI will output the INT signal So when RO 0 the motor will stop and the LSI outputs the INT Further by setting bit 5 1 output an INT when stopped in the start mode command the LSI can output another INT signal when the motor is stopped By checking whether bit 4 1 PC 0 monitor in status register 0 the LSI can make RO 0 stop the motor and output an INT We would like to run a preset constant speed operation using the PCD4521 We set the rampdown point RO 0 and set it to output an INT signal at the rampdown point However when the RO becomes 0 the motor stops but the PCD does not output the INT signal at the rampdown point We have pulled the INT signal terminal up Can we output the INT signal by setting an INT output at the rampdown point if we set the rampdown point to RO 0 in continuous operation It is possible to output a rampdown point INT when the preset counter reaches 0 and the rampdown point is set to 0 In both preset and continuous operations set bit 4 in the register select command to 1 The PCD will output an INT signal when the reset value the rampdown point However the PCD will output a rampdown point INT whenever the conditions are met assuming that the preset value rampdown po
23. ng at the preset counter to see if it is 0 You can see whether the preset counter is 0 by reading RO or bit 4 in status register 0 To see whether an EL signal was input you can check bits 0 or 1 in status register 1 However the status register only reflects the instantaneous condition at the moment when the register is read Therefore if the PCD was stopped by EL turning ON and EL has gone OFF again before you read the status register you may not be able to see why the PCD was stopped The same is true for reading the residual pulses RO 0 However in this case if the residual pulse count is 0 you may be sure that the PCL was stopped by the preset operation Since the SD and EL lines are pulled up internally is there any problem with leaving them open when they are not being used They may be left open However to enhance noise prevention connect them directly to a 5V terminal or through a 1 K ohm external resistor We write a start command while the EL signal is ON Then we turn OFF the EL signal Is it normal for the PCL to start operation at this point The stop circuit using the EL signal stops the start circuit by ORing detecting the OFF to ON edge and latched signal of the EL with the EL level signal By turning ON the EL signal the latched signal is cleared by a reset command 08H Therefore after turning ON the EL signal write a reset command and a start command Then turn OFF the EL signal The PCD will start o
24. nt speed mode is overwritten during operation Method for checking Read the start mode command using the extension monitor 3 The FL speed is overwritten with the same value used for the FH speed Method for checking Read the R1 FL register value 4 Bit 3 stop acceleration deceleration in the middle of the output mode is 1 Method for checking Read the output mode command using the extension monitor 5 Triangle driving with S curve acceleration deceleration is occurring Method for checking Check whether the preset amount 2 is greater than R5 The recommended reference clock for the PCD series is 4 9152 MHz Will there be any problem witha 4 MHz or 5 MHz clock What is the minimum frequency There is no minimum value Since the PCL can use a clock up to 10 MHz there is no problem with using a 4 MHz or 5 MHz clock We recommend 4 9152 MHz for the following reasons Some formulas are provided in order to determine the values to put in various registers In some of these formulas you have to use the reference clock frequency In particular when setting the register for the frequency multiplication rate if you enter 4 9152 MHz the result will be an integer no number on the right of the decimal point This is rather convenient for determining the pulse frequency When using values other than 4 9152 MHz the output pulse frequency will be a number with a fraction and it may be inconvenient for calculations and other settings However ther
25. oning control operation it is better to use the idling pulses and a higher FL value Then increase the acceleration speed use a small acceleration rate We want to change the acceleration deceleration times Can we overwrite them while accelerating decelerating If the acceleration deceleration rates are changed during acceleration deceleration the PCD may not change the speed for 1023 reference clock cycles while overwriting with some write timing Therefore we recommend changing the acceleration deceleration rate registers during constant speed operation It is better to change the rates after confirming that bits 6 and 7 of Status Register 0 are 00 NOT accelerating decelerating constant speed operation We are using a PCD series device After starting with an FH high speed start the motor does not decelerate when the rampdown point is reached To decelerate using the rampdown point start the motor with an FH high speed start in preset operation and when RO preset counter becomes less than R5 rampdown point setting register the target speed will change to FL speed Then the deceleration will start Possible explanations for why the PCD does not decelerate when the rampdown point is reached are as follows 1 The R5 rampdown point set register value is not appropriate Method for checking Read the R5 register value gt See if bit 5 PC lt R5 in Status 0 is 1 when you are within the rampdown point range 2 The consta
26. onitor on pages 18 and 43 of the user s manual These examples concerning status 0 are based on the assumption that RO to R7 are intentionally selected This should help you understand how when A1 0 and A0 0 the contents of status 0 can be read As above when reading status 0 there is no need to select a register 2 Status 1 2 3 As shown in the table When the extension monitor is selected on pages 18 and 43 of these user s manuals these status registers cannot be read unless R7 is selected using the register select command Select R7 to read the following e A1 0 A0 1 Status 1 e A1 1 A0 0 Status 2 e A1 1 A0 1 Status 3 When the standard monitor is selected status 2 and 3 and R1 to R7 cannot be read This is done to maintain compatibility with a single axis PCD4500 We want to start four axes simultaneously with the PCD4541 Normally we select an axis and trigger a start for this axis But if we write a start hold command to each axis and then provide an external signal through the STA terminal can we start all the axes simultaneously Yes you can After inputting the STA signal each axis will have a time lag of a few clock cycles before the first pulse is output However pulse output timing will be exactly the same for all the axes We want to self start from any position and move to the position set by preset counter RO 0 stop the motor immediately at the RO 0 position and output the INT signal I
27. opposite direction from that used by the EL to stop When the signal EL is input by a pulse signal the current output clock will stop However the motor can be restarted without taking any further action How is it possible to start a zero return operation while the ORG signal is ON The PCD series does not start the zero return The zero return operation is delayed When the ORG signal is released they will start to return to the zero position LSIs with the zero position leave function such as the PCL 60xx series can be operated even if the ORG signal is ON by using certain setting methods Can we supply a signal to EL directly from a switch or sensor If the signal on the line is normally open and active LOW it can be input directly In order to prevent problems from electrical noise insert an isolation router on the line Is there any model that can accept input from an absolute encoder gray code All of PCD PCL series and CCL series will only accept incremental type encoder signals there is no model that accepts absolute encoder signals Is it possible to use these LSIs at ambient temperatures of 100 deg How about operation at lower temperatures The LSIs cannot be operated at temperatures of 100 degrees However the temperature conditions vary a little with each model For details see the user s manual for each model and operate the chip within the specified temperature range Why do we set bit 3 stop an acceler
28. peration This is basically the same for the PCL series Can we use the EL SD and ORG terminals for general purpose input The EL terminal always stops the PCD operation and cannot be used as a general purpose input The ORG input can be used as a general purpose input if bit 0 0 disable ORG signal in the control mode command Also the SD input can be used as a general purpose input if the control command bit 0 1 disable the SD signal After an FH high speed start the PCD accelerates in the positive direction But it does not accelerate in negative direction It only feeds at FL speed Why If this symptom always occurs the SD signal may be turned ON LOW After the SD signal goes ON and the motor reaches FL speed if the SD signal goes OFF will the motor accelerate again If the SD signal goes OFF the motor accelerates Even if the motor is decelerating it will instantly begin accelerating if the SD signal goes OFF We would like to provide protection for the circuits in order to prevent damage to the PCD chips driving ICs and motors against abnormal use by users who use the PCD chip in built in units What equivalent excitation sequence signal output circuits for the PCD series are available The equivalent circuit for one phase is as shown in the figure on the left The equivalent circuit is the same for all models of the PCD series Using the PCD series is there any method to decelerate and stop using the STP sign
29. ration deceleration rate while operating at FH speed so that you can decelerate using a new rate However if you overwrite the acceleration deceleration rate during acceleration the motor will not change speed will not begin to accelerate for a period of 1023 x reference clock cycles when you overwrite the rate at certain points Therefore if you want to change the acceleration deceleration rate register it is better to do it during constant speed operation It is better to overwrite the rate after confirming that bits 6 and 7 of status 0 are 00 in a speed operation other than an acceleration deceleration Is the value put in the speed register a division ratio The larger value the lower speed The value is divided in the circuit However the value put in the speed register is the numerator not the denominator Therefore when the reference clock is 4 9152 MHz and R4 600 1x mode the speed register value will be equal to the speed pps While in preset operation I want to decelerate and stop the motor In this case can I reset 0 the residual pulses in RO If so how There is no command that can be used to reset RO If residual pulses remain in RO and you trigger a restart the PCD will output the residual pulses and then stop If there are residual pulses in RO write a new value to RO The old value will be overwritten and the new value will be used Therefore you can write RO 0 when the motor decelerates and stop
30. s Are triangle operation trapezoid operation constant speed and one pulse feeding all permitted as speed patterns The four patterns named in the question are all possible In the case of triangle operation in preset operation when the feed amount the number of pulses to output is small the PCL will decelerate the motor while still accelerating from FL speed to FH speed Then when the motor reaches FL speed again it will stop the motor One pulse feeding is possible by putting a 1 in the countdown counter RO and triggering a start In the register calculation files in the Excel document for the PCL series there is a data calculation formula for triangle driving Is there a function that can be used with the PCD series to lower the FH speed and make the apex of the triangle flat in order to prevent triangle driving Should users calculate and set the FH and rampdown point R5 themselves In the PCD series when the following condition is met The Preset Amount R0 lt Rampdown point setting x 2 The motor will not reach the originally set FH speed It starts decelerating when the following condition is met RO Rampdown point set value Thus the operation pattern will be triangle driving There is no function in the PCD series that will automatically make the apex of the triangle flat You should determine whether the operation will be a triangle shape or not and then you can set the FH speed and rampdown point R5
31. s That is the ramp down point Without this setting and since the initial value is 0 the pulses will stop when the preset counter counts down from the FH speed and reaches 0 All of the PCL series have an automatic ramp down point setting function There are two concepts used for carrying out this function in the different models The internal processing method for the two concepts is different However the models listed above apply the concept of counting the number of pulses used for acceleration and using this value in the ramp down point register so that you do not need to set the ramp down point as a separate operation The PCD series puts a priority on lowering the cost and the automatic ramp down point function has been omitted Therefore you need to set the ramp down point yourself We want to use 6 PCD chips on one board sharing the same oscillator in order to reduce the number of reference clock oscillators Please let us know about any precautions and the items to check for in this case Refer to DC characteristics in the electrical characteristics on page 50 in the PCD4511 4521 4541 user s manual If the three items input signal capacity low level input current and high level input current are satisfied you may share the use of an oscillator This applies to all the chips in the PCD PCL series Are there any requirements for the rise and fall time of the reference clock There are no special requirements The CLK inp
32. st after output pulse level changes from LOW to HIGH the no positional error will occur It depends on the actual frequency and the CPU processing speed To check the state of the level watch for a change in the lowest bit 101010 of the countdown counter using a CPU Using the PCD series is there any method for confirming the end of acceleration We use a sequence to start measurements when the motor enters constant speed operation after acceleration We imagine that the end of the acceleration can be identified by the number of output pulses and the measuring times The PCD series has no direct way to tell other than by polling to check the acceleration deceleration status The interrupt process and the polling process can be used to check the status of the PCL With the PCL if you use an interrupt process you have to set the PCL to generate an interrupt when the acceleration stops The CPU executes other operations until the interrupt is received When an interrupt is received the CPU will look at the PCL status In the interrupt process the CPU processes the interrupt only when an interrupt is received and the burden on the CPU is quite small However the program can be rather complicated On the other hand in the polling process the CPU reads the PCL status at certain intervals and monitors when it has stopped accelerating If you want to monitor the PCL on a real time basis this interval between checks must be quite short With
33. t operation without acceleration deceleration read the status 0 condition when stopped e Ina preset operation using acceleration declaration read the condition of status 0 when the motor is stopped Please let us know which actions and interrupt status occur when the following operation is triggered during the preset operation The PCD handles setting of each of the mode and overwrite register values while operating as a change in the current operation The start mode command is not an exception But the PCD will not accept the start command of the next operation If handle the start command as a change in the current operation In other words after starting the motor with an FH high speed start in preset operation and writing a deceleration stop command a kind of start command the motor will decelerate and stop from that point I do not understand how to read the status using the PCD4541 For example the address of status 0 is A1 0 and AO 0 Does this mean that we are reading the contents of the command buffer To say it simply you may understand that each address stores the data for writing and the data for reading separately 1 Status 0 The PCL writes A1 0 and AO 0 to the command buffer When you want to read the data the contents of status 0 will be output to the data bus See page 16 of the PCD4511 4521 4541 user s manual You can find tables describing Setting a standard monitor and Setting an extension m
34. the polling process the CPU monitors the status frequently which places a heavy burden on the CPU This program is rather simple We want to change the acceleration and deceleration time Can we do this during acceleration If the motor is rotating at FH constant speed there is no problem with overwriting the acceleration deceleration rate However if the acceleration deceleration rates are overwritten while actually accelerating decelerating it is possible the speed will not change for 1023 reference clock cycles it will not accelerate during this interval We want to overwrite the RO register during preset mode operation During operation in the preset mode if we write new data to RO before the preset number of pulses has been output before stopping How will the PCL behave Does the PCL continue the preset mode operation with the new RO value until the number of residual pulses becomes 0 Or is overwriting RO not allowed until the current operation is complete Or will it have another effect The PCL will continue the preset mode operation until the number of pulses according to the new RO value reaches zero However when overwriting RO the PCL keeps outputting pulses so that it is not possible to aim for a precise target position During an operation in continuous mode if we overwrite the R2 value and write a high speed command that is in the opposite direction from the current operation How will the PCL behave If we write a hi
35. ut is a Schmitt trigger input H 3 V L 1 7 V A little smoothing of the rising falling edges can change the internal shape Do not use a clock with a pulse width less than 50 ns When inserting and removing the power supply connector while the power is on may damage the LSI What are the possible causes and symptoms Precautions you should take before inserting or removing power supply connector 1 D Should not exceed the absolute maximum rating even for a short time When the absolute maximum rating is exceeded the possible symptoms may vary with the level of the excess voltage When the voltage on the power terminals significantly exceeds the rating the semiconductor insulation layer may be damaged and the element itself may be damaged as well If the overvoltage level is small the LSI may malfunction or some of the I O elements might fail or latch up Also if the specified input voltage is greatly exceeded the semiconductor insulation layer may be damaged If the overvoltage level is small some of the I O elements might fail or latch up If the input current exceeds the continuous rating the I O elements may be destroyed by heat At some storage temperatures the plastic case and elements may deteriorate The I O terminal voltage should never be above VDD and it should never be below GND Also consider the power input timing If the I O terminal voltage level exceeds VDD or drops below GND it will be the same as for overvoltag
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