CXM544 User`s Manual - Willow Technologies
Contents
1. 12 4 5 Common Command Examples rrrrrnvrnrvrnvvrnrrrnnrrnrrrssrrssrrsersneenne 13 4 6 Verifying Proper Operation of the System ew w wwewe 14 5 Description of the CXM544 Orientation Angles 17 5 1 Sensor Based Coordinate System sss 17 5 2 Definition of Orientation Angles sese 17 5 3 Defitiitiohs AE 18 5 4 Calculation of Roll and Magnetic Roll 19 5 5 Calculation of Inclination essen 19 5 6 Magnetic Heading Azimuth Yaw sse 20 6 Appendix A Mechanical Specifications 21 6 1 CXM544 Outline Drawing sse 21 7 Appendix B CXM544 Command and Output Interface 22 7 1 CXM544 Heading Sensor Command Set suuus 22 Doc 7430 0117 01 Rev A Page iii Crossb w CXM544 User s Manual 8 Appendix C Warranty and Support Information 28 8 1 Customer SEVIA oce ane E p eiie itam dreid 28 8 2 Contact Directory cis seite teint etre al aweka 28 8 3 Return Procedure no Soe ete d ie dusker 28 8 4 Watt anty ooge onson M 29 Page iv Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w About this Manual The following annotations have been used to provide additional information 4 NOTE Note provides additional information about the topic VI E2. Crossb w CXM544 User s Manual The CXM544 system accelerometers are calibrated by placing the system in a precision rotation fixture and systematically changing the system orientation in the earth s gravitational field The CXM544 system magnetometers are calibrated by placing the system in a precision 3 axis Helmholtz coil system which enables the application of known magnetic fields to the system Both the rotation fixture and Helmholtz coil have alignment pins and reference surfaces which mate to the CXM544 reference surface System calibration can be performed at a base temperature usually 25 C or over a temperature range for example 15 90 C When the system is calibrated over a temperature range data is read from the system at temperature intervals between the minimum and maximum temperature specification For in stance for calibration over the interval of 15 90 C data is usually read at 25 C temperature intervals between 15 and 90 C The data taken at each temperature includes scale offset and sensor alignment data The recorded data is then used to create a look up table for scale offset and alignment corrections This table is then downloaded into the CXM544 internal EEROM memory where it can be accessed by the system internal microprocessor Corrections to the read sensor data can then be made by the internal microprocessor system before data is transmitted 1 1 Package Contents In addition to your CXM544 product you
3. 0117 01 Rev A CXM544 User s Manual Crossb w 5 Description of the CXM544 Orientation Angles This application note describes how to calculate the roll pitch and azimuth angles for the CXM544 orientation sensor from accelerometer and magnetometer output data 5 1 Sensor Based Coordinate System The coordinate system of the CXM544 system is defined in Figure 1 The accelerometer and magnetometer coordinate systems are both aligned with the physical package coordinate systems shown For the magnetometer sensors a positive output voltage will result if the sensor is pointed north For the accelerometers a positive voltage will result if the sensors are pointed down Inclination Down Figure 1 CXM544 Coordinate System 5 2 Definition of Orientation Angles The orientation angles are defined in Figure 2 Azimuth or yaw is defined as the angle measured from magnetic north clockwise from above to the projection of the x axis on the horizontal plane Doc 7430 0117 01 Rev A Page 17 Crossb w CXM544 User s Manual North Magnetic Roll UP Roll 30 as shown 20 as shown 544 Reference Surface 544 Reference Wires Surface Wires Zz Figure 2 CXM544 Orientation Angles Inclination is the angle that the x axis makes with the down direction and is 0 when the x axis is down and 90 when the x axis is horizontal Roll or gravity tool face is defined as the angle of counterclockwise rotation about the x ax
4. RTS Delay is the time in 2 millisecond units that the RTS line is high before data is sent Any value but 0 will slow the data rate by the same amount Doc 7430 0117 01 Rev A Page 27 Crossb w CXM544 User s Manual 8 Appendix C Warranty and Support Information 8 1 Customer Service As a Crossbow Technology customer you have access to product support services which include e Single point return service e Web based support service e Same day troubleshooting assistance e Worldwide Crossbow representation e Onsite and factory training available e Preventative maintenance and repair programs e Installation assistance available 8 2 Contact Directory United States Phone 1 408 965 3300 8 AM to 5 PM PST Fax 1 408 324 4840 24 hours Email techsupport xbow com Non U S referto website www xbow com 8 3 Return Procedure 83 1 Authorization Before returning any equipment please contact Crossbow to obtain a Returned Material Authorization number RMA Be ready to provide the following information when requesting a RMA e Name e Address e Telephone Fax Email e Equipment Model Number e Equipment Serial Number e Installation Date e Failure Date e Fault Description Page 28 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w 8 332 Identification and Protection If the equipment is to be shipped to Crossbow for service or repair please attach a tag TO THE EQUIPMENT as well as the shipp
5. gt lt MZ gt lt AZ gt lt MT gt lt AT gt lt 0 gt lt DATACHKSUM gt lt END gt size 8b 16b 16b 16b 16b 16b 16b 16b 16b 8b 8b 16b in bits If The Command is 131 lt NUM DATA BYTES gt lt Roll gt lt MRoll gt lt Pitch gt lt Mag gt lt Head gt lt Grav gt lt MT gt lt AT gt lt 0 gt lt DATA CHK SUM gt lt END gt size 8b 16b 16b 16b 16b 16b 16b 16b 16b 8b 8b 16b in bits lt END gt 0x7FFF is unique in the data stream lt NUM DATA BYTES gt 16 lt 0 gt a constant 0 to allow END to be unique DATA CHECK SUM gt The lower 8 bits of the sum of all the bytes in the data area lt Roll gt The Roll data encoded as below lt Pitch gt The Pitch data encoded as below lt Head gt The Heading data encoded as below lt MRoll gt The Magnetic Roll data encoded as below Page 24 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w lt Mag gt The Total Magnetic Field data encoded as below lt Grav gt The Total Gravitational Field data encoded as below lt MX gt lt MY gt lt MZ gt The Magnetometer data encoded as below lt AX gt lt AY gt lt AZ gt The Accelerometer data encoded as below lt MT gt lt AT gt The Temp data encoded as below All data is sent most significant byte first If the correction mode is 0 the Magnetometer and Accelerometer data is in a two byte signed integer format in counts If the correction mode is 1 or 2 the Magnetometer and Accelerometer d
6. pedde 99 7 g 1ejeureip 79070 v uonduoseg 9JoH wo Z LL uo 6L OV re L0 ven ut epe XXXXX ON WHS UOSNAS wo p LL 00 T S r Y cooococ wo 7 08 0 21 zoo 20510 4 200 0SL0 sen are in inches Page 21 Doc 7430 0117 01 Rev A Crossb w CXM544 User s Manual 7 Appendix B CXM544 Command and Output Interface 7 1 CXM544 Heading Sensor Command Set Addressed Command is lt Address gt lt Command gt lt CR gt An Address is lt 0 9 A Z gt CR is a Carriage Return Axis is lt X Z T gt Constant Number is lt 00 99 gt Constant Value is lt lt number gt lt number gt gt Constant String is lt A Z 0 9 gt lt Constant String gt A number is lt lt 0 9 gt number gt A command consists of one of the following Send All Data SD All Data is sent MX 4 AX AHHH lt CR gt lt LF gt as requested MY HE fH AY st HAHHE lt CR gt lt LF gt raw vectors or MZ XH AHBHBE AZ tH HHHH lt CR gt lt LF gt angles as set by MT HHH HHEXCR gt lt LF gt byte constant 2 AT H AHHH lt CR gt lt LF gt lt EOT gt Send Anal Input SA ANA lt CR gt lt LF gt lt EOT gt Read Float Constant SC lt Constant Number gt F LETHE EH A lt CR gt lt LF gt lt EOT gt Read All Float Constants SC F 00 01 HHHHHHHHHCEIHECRPLE HHHHHBHHHEEIHESCRALE HH HATH E lt CR gt lt LF gt lt EOT gt Read Byte Constant SC lt Constant Number gt B lt CR
7. CR gt lt LF gt lt EOT gt Test Serial Port TS Always Echoes OK lt CR gt lt LF gt lt EOT gt Return Software Version TV Ver 4 lt CR gt lt LF gt lt EOT gt Enable Low Level Writes L Enabled lt CR gt lt LF gt lt EOT gt Write Float To Constant WC lt Constant Number gt F lt Value gt Done lt CR gt lt LF gt lt EOT gt Doc 7430 0117 01 Rev A Page 23 Crossb w CXM544 User s Manual Write Byte To Constant WC lt Constant Number gt B lt number gt Done lt CR gt lt LF gt lt EOT gt Write Int To Constant WC lt Constant Number gt B lt number gt Done lt CR gt lt LF gt lt EOT gt All Commands marked with an require the Enable Low Level Writes command to be executed as the previous command for successful execution All Commands Marked with a execute differently when Enable Low Level Writes was executed as the previous command lt 128 gt Send All Data as Vectors in a Binary Format lt 129 gt Send All Data as Vectors in a IEEE Float Format lt 131 gt Send All Data as Angles in a Binary Format 132 Send All Data as Angles in a IEEE Float Format lt 128 gt and lt 131 gt Sends All Data in an encoded Binary Format in the current format as selected by Byte constant 2 If the correction mode is 0 1 or 2 the data is returned as Sent First Sent Last lt lt lt lt If The Command is 128 lt NUMDATABYTES gt lt MX gt lt AX gt lt MY gt lt A Y
8. CXM544 User s Mam Revision A March 2005 Document 7430 0117 01 Crossb w Crossbow Technology Inc 4145 N First Street San Jose CA 95134 Tel 408 965 3300 Fax 408 324 4840 email info xbow com website www xbow com 1999 2005 Crossbow Technology Inc All rights reserved Information in this document is subject to change without notice Crossbow and SoftSensor are registered trademarks and DMU is a trademark of Crossbow Technology Inc Other product and trade names are trademarks or registered trademarks of their respective holders CXM544 User s Manual Crossb w Table of Contents 1 Description of the System 4 eere ecce eee eee eerte ee en ne etnue 1 1 1 PackageContents sherr mE RH AERE its 2 2 Electrical and Mechanical Interface eres 3 2 1 Electrical Interface eerie reis 3 2 2 Mechanical Features esee 3 2 3 Communication Interface sess 4 3 eiu dnagmee 5 3 1 MagView Software mikia ika kaaa 5 3 2 COMNECHONS aa 5 3 3 Setup Mag View intente re e eh e Ve de edd 6 3 4 Take Measurements ense iere ee RR Gees aeons 6 4 System Startup and Checkout e eeeeeeeeeeeee 7 4 1 Initial Setup of the System seen 7 4 2 Operation of the System sss 8 4 3 Binary Mode Operation sss 10 4 4 Descriptions of the System Internal Constants
9. XAMPLE Examples are given throughout the manual to help the reader understand the terminology IMPORTANT This symbol defines items that have significant meaning to the user 6 WARNING The user should pay particular attention to this symbol It means there is a chance that physical harm could happen to either the person or the equipment The following paragraph heading formatting is used in this manual 1 Heading 1 1 1 Heading 2 1 1 1 Heading 3 Normal Doc 7430 0117 01 Rev A Page v CXM544 User s Manual Crossb w 1 Description of the System The CXM544 Orientation Sensor system contains both a 3 axis fluxgate magnetometer and a 3 axis accelerometer The combination of these two sensor systems enables the roll pitch and azimuth angles of the CXM544 reference frame with respect to the local gravity and magnetic field vectors to be determined Roll and pitch angles are determined from the accelerometer subsystem which measures the orientation of the system with respect to the gravity vector After roll and pitch are known the magnetometer subsystem is used to determine the azimuth angle of the system Knowledge of the roll and pitch angles enable determination of the horizontal components of the earth s local magnetic field this information defines the azimuth angle The CXM544 system also contains a microprocessor and 7 channel 16 bit analog to digital converter Six channels are assigned to the magnetometer and
10. a In IEEE mode in a loop until AutoStart is not 0x5A 09 User power on baud rate lock if not Ox5A sensor will use 9600 Baud 10 User power on baud rate Use With Caution Baud 10 Baud 10 75 37 1200 33 150 36 2400 32 300 35 4800 31 600 34 9600 30 Page 26 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w 11 Not Used 12 Lowest Calibration Temp in counts LSB 13 Lowest Calibration Temp in counts MSB 14 Distance in counts between Calibration Points LSB 15 Distance in counts between Calibration Points MSB 16 Number of Temp Points in the SEEROM 17 The Table Magnetometer Offset Scale Value Offset TableOffset 2 lt Bytett18 gt 18 The Table Accelerometer Offset Scale Value Offset TableOffset 2 lt Bytett19 gt 19 The Table Mag Scale Scale Value Scale TableScale 2 lt Byte 20 gt 20 The Table Acc Scale Scale Value Scale TableScale 2 lt Byte 21 gt 21 The Table Mag Ortho Scale Value Ortho TableOrtho 2 lt Byte 22 gt 22 The Table Acc Ortho Scale Value Ortho TableOrtho 2 lt Byte 23 gt 23 Not Used 24 Product I D String char 1 25 Product I D String char 2 26 Product I D String char 3 27 Product I D String char 4 28 Product I D String char 5 29 Product I D String char 6 30 Product I D String char 7 31 Product I D String char 8 32 Product I D String char 9 33 Product I D String char 10 34 Constant 0 35
11. accelerometer outputs One channel provides temperature data from an internal thermometer The functions performed by the system microprocessor and A to D subsystem are 1 Conversion of the sensor analog outputs to digital form 2 Calibration of the sensor scale offset and alignment factors for a temperature variation and 3 Implementation of serial communications between the system and an external computer The CXM544 communicates with the outside world over one of two serial bi directional interfaces which can be selected from either TTL or RS232 voltage levels An ASCII character command language has been created to facilitate communication with the CXM544 For in stance if the ASCII characters for 0 S and D are sent in sequence the CXM544 interprets this as a send data command and responds by sending over the serial interface an ASCII string representing the value of all magnetometer accelerometer and temperature outputs The leading zero in this sequence denotes the system serial number The CXM544 can also be configured to send angle data roll pitch and azimuth instead of the accelerometer and magnetometer sensor data An auto send data mode is included in the MagView software When this mode is active data is repeatedly sent after power is applied to the system at a rate of two transmissions per second in angular output mode and three times per second in magnetometer accelerometer out put mode Doc 7430 0117 01 Rev A Page 1
12. ata is in a two byte signed integer format encoded as the float value times 10000 1 2345 12345 If the correction mode is 3 the data is angles and is represented in a two byte signed integer format encoded as the float value times 10 123 45 1234 The Temp data is in a two byte signed integer format encoded as the float value times 100 123 45 12345 lt 129 gt and 132 Sends All Data in IEEE Floating point format in the current format as selected by Byte constant 2 If the correction mode is 0 1 or 2 the data is returned as Sent First lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt lt Sent Last lt lt lt lt If The Command is 129 lt NUM DATA BYTES gt lt MX gt lt AX gt lt MY gt lt A Y gt lt MZ gt lt AZ gt lt MT gt lt AT gt lt 0 gt lt DATA CHECK SUM gt size 8b 32b 32b 32b 32b 32b 32b 32b 32b 8b 8b in bits If The Command is 132 NUM DATA BYTES gt lt Roll gt lt MRoll gt lt Pitch gt lt Mag gt lt Head gt lt Grav gt lt MT gt lt AT gt lt 0 gt lt DATA CHECKSUM gt size 8b 32b 32b 32b 32b 32b 32b 32b 32b 8b 8b in bits lt END gt 0x7FFF is unique in the data stream NUM DATA BYTES 16 07 a constant 0 to allow END to be unique Doc 7430 0117 01 Rev A Page 25 Crossb w CXM544 User s Manual lt DATA CHECK SUM gt The lower 8 bits of the sum of all the bytes in the data area lt Roll gt Th
13. be configured to output in raw ADC counts sensor values or angles The following example shows how to change the sensor configuration to use angle mode See Table 5 for a description of other possible values OL lt CR gt 0WC02B03 lt CR gt Doc 7430 0117 01 Rev A Page 13 Crossb w CXM544 User s Manual 45 5 Changing the Baud Rate The communications baud rate can be changed by using the following sequence 1 Set byte constant 10 according to Table 6 More values can be found in Appendix B 2 Set byte constant 09 to 0x5A 3 Cycle power to the CXM544 to activate the new baud Table 6 Baud rate changing commands for CXM544 Constant 10 value Baud rate 35 300 33 1200 32 2400 31 4800 The following commands illustrate setting the baud rate to 2400 OL lt CR gt OWC10B32 lt CR gt OL lt CR gt OWCO09BSA lt CR gt 4 NOTE When byte constant 09 is set to any value other than 0x5A the system baud rate is 9600 45 6 Request Binary Data To request a binary data packet the user sends a single byte command However the total command must still start with the address 0 and lt CR gt end To request a binary data packet in sensor mode send the following command 0 lt 128 gt lt CR gt where lt 128 gt is the single byte 0x80 To request a binary data packet in angle mode send the following command 0 lt 131 gt lt CR gt where lt 131 gt is the single byte 0x83 See Section 4 3 f
14. e Roll data lt Pitch gt The Pitch data lt Head gt The Heading data lt MRoll gt The Magnetic Roll data lt Mag gt The Total Magnetic Field data lt Grav gt The Total Gravitational Field data lt MX gt lt MY gt lt MZ gt The Magnetometer data lt AX gt lt AY gt lt AZ gt The Accelerometer data lt MT gt lt AT gt The Temp data All data is sent most significant byte first Byte Constant Numbers and Their Meanings 00 Command Echo Flag 0 is no command echo anything else echo commands 01 Autostart Flag If Ox5A executes the selected autostart option on powerup 02 Correction Level 0 Raw 2 Vectors 3 Angles In Angles mode Roll is labeled MX Pitch is labeled MY Heading is Labeled MZ Magnetic Roll is labeled AX Total Magnetic Field is labeled AY Total Grav Field is labeled AZ 03 Months since 1 90 when device was calibrated 04 Version of the Calibration Software used 05 Power on self test flag If zero a self test will be done on power up 06 Enable extended error messages 07 This Sensor s Address Number 0 36 gt 0 9 A Z 08 Auto Start Mode on powerup start accepting commands then 0x00 Send all data in text mode once 0x01 Send all data In Binary mode once 0x02 Send all data In IEEE mode once 0x10 Send all data in text mode a loop until AutoStart is not OxSA 0x11 Send all data In Bin mode in a loop until AutoStart is not 0x5A 0x12 Send All Dat
15. for ASCII or BINARY transfer mode and corrected or non corrected data Log files of sensor data can be created A scrolling graph of the digital data and graphical indicators of the angular data are displayed to the operator Minimum and maximum values are maintained for the magnetometer and the accelerometers 3 1 1 MagView Computer Requirements The following are the minimum capabilities that your computer should have in order to run MagView successfully e CPU Pentium Class e RAM 32MB minimum 64MB recommended e Operating System Windows 98 NT4 2000 XP 3 12 Install MagView To install MagView software on to your computer 1 Insert the CD Support Tools in the CD ROM drive 2 Find the MagView folder and copy it over to your desktop and the software ready to use If you have any problems or questions you may contact Crossbow directly 3 2 Connections The CXM544 is shipped with a ribbon cable to connect the sensor to a PC COM port 1 Connect the 9 pin end of the digital signal cable to the port on the CXM544 2 Connect the other 9 pin end of the cable with backshell to the serial port of your computer 3 The additional black and red wires on the cable supply power to the Sensor Match red to power and black to ground The input voltage can range from 7 5 15 VDC See the specifications for your unit Doc 7430 0117 01 Rev A Page 5 Crossb w CXM544 User s Manual WARNING Do not reverse the powe
16. from the system by sending typing the command 0SD lt CR gt 0 Send Data The 0 in this sequence is the de fault serial number of the unit After sending this command the CXM544 will respond with an output that appears as follows MX 0 5432 AX 0 9456 MY 0 1234 AY 0 4510 MZ 1 0145 AZ 0 0112 t 45 0 The numbers following the MX MY and MZ headers represent the sensor magnetometer output in Gauss The numbers following the AX AY and AZ headers represent the accelerometer output in gees The temperature C follows the t header The above outputs represent data sent when the CXM544 is in sensor mode If angular data is required the system mode will need to be changed In general the CXM544 operating characteristics are controlled by the values of internal byte constants These constants are stored in the system EEROM and can be changed by a two step process The two step process 1s used for Page 8 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w security reasons to ensure that these constants are not inadvertently changed To change the CXM544 to angle mode byte 02 must be changed from 02 sensor mode to 03 angle mode To accomplish this type O0L lt CR gt The unit will respond with the message enabled Next type the sequence 0WC02b03 CR 0 Write Constant 02 byte 03 The unit will respond by sending the message done Now request data by sending the sequence 0SD lt CR gt The response will look so
17. gt lt LF gt lt EOT gt In Hex Read All Byte Constants SC B 00 lt CR gt lt LF gt In Hex 01 lt CR gt lt LF gt lt EOT gt THE lt CR gt lt LF gt lt EOT gt Read int Constant SC lt Constant Number gt I lt CR gt lt LF gt lt EOT gt Read all int Constants SC I 00 HHHHE lt XCR gt lt LF gt Page 22 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w 01 HHHHE lt CR gt lt LF gt lt EOT gt HH HH lt CR gt lt LF gt lt EOT gt Reset A D RA Done lt CR gt lt LF gt lt EOT gt Test ROM Checksum TC if low level writes are enabled the output is STORED HHHH lt CR gt lt LF gt lt EOT gt If low level writes are not enabled and the Checksum of the ROM is the same as the one stored HHHH lt CR gt lt LF gt lt EOT gt else the Output is ERR HHHH lt CR gt lt LF gt lt EOT gt Test EEROM Checksum TE if low level writes are enabled the output is STORED HHHH lt CR gt lt LF gt lt EOT gt If low level writes are not enabled and the Checksum of the ROM is the same as the one stored HHHH lt CR gt lt LF gt lt EOT gt else the Output is ERR HHHH lt CR gt lt LF gt lt EOT gt Test RAM TR Either an OK or an error OK lt CR gt lt LF gt lt EOT gt The Error Addr is in Hex ERR AT HHHH lt CR gt lt LF gt lt EOT gt Test EEROM Read Write TW This takes up to 10 Seconds Either an OK or an error OK lt CR gt lt LF gt lt EOT gt The Error Addr is in Hex ERR AT HHHH lt
18. h an external computer must be set up Powering will depend upon whether the unit is using a 5V supply or the internal regulators and powers from 7VDC to 12VDC To ensure system accuracy the 5V powered system must be within 0 05V of 5V Connect the correct power lead to the selected supply voltage See Table 1 After powering the system should consume about 71 mA of input current In order to set up a computer interface with the system select the output protocol of the CXM544 This can be either TTL or RS232 The TTL protocol is usually used in microprocessor to microprocessor communications For this mode the voltage levels for a 0 and are approximately ground and 5V In the idle or marking state the output level is 5V The RS232 protocol is used by using serial com ports RS232 voltage levels for a 0 and a are approximately 5V and 5V In the idle or marking state the 5V level is output About 1 second after power up the CXM544 will send out a sign on message This can be observed with an oscilloscope as a series of transitions from 5 to 0V TTL or 5V to 5V RS232 Since PC s use RS232 protocol they can be directly connected to a CXM544 employing this protocol PC s use either a 25 pin or a 9 pin D connector to implement their serial ports This connector is always a bulkhead male connector on the PC chassis The serial in serial out and ground connections for these connectors are as follows Table 3 Seria
19. if any baud rate other than 9600 is to be used 10 Sets baud rate Page 12 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w VI EXAMPLE 45 Common Command Examples All commands should start with the character 0 zero and end with a lt CR gt carriage return You need to send the command OL before each command to change a byte constant Refer to the Appendix B for a detailed description of the 544 command set 45 Geta data packet To receive a single data packet use the send data command OSD lt CR gt The CHS Sensor will respond with a single data packet 45 2 Read the byte constants The configuration of the CXM544 is controlled by the values of its internal byte constants To read out the current values of the byte constants use one of the following commands The CXM544 will respond with the current value in hex To read a single specific constant use the following OSC lt number gt B lt CR gt where lt number gt refers to the address of the constant you want to read The number should be typed in the format 00 99 To read all constants use the following OSC B lt CR gt 4 5 3 Make the CXM544 Echo You may want the CXM544 to echo the characters sent to it so that you can verify your communication To do this you need to set the value of the byte constant 00 to be non zero OL lt CR gt OWC00B01 lt CR gt 4 5 4 Change Data Output Mode The CXM544 can
20. in concrete floors etc In this case verifying azimuth accuracy to 1 is difficult Use a compass to orient the CXM544 approximately horizontal and East inclination 90 azimuth 90 Carefully align the CXM544 along x axis so that it is pointed East and verify that the azimuth reading is 90 1 0 Use the same procedure to verify azimuth accuracy for 180 270 and 0 readings In sensor mode byte 02 02 the CXM544 accelerometer sensors should read 1 00 and 1 00 when pointed down and up respectively Therefore when lying flat on a horizontal surface with the z axis pointed down the x and y accelerometers should read 0 0 01 and the Z accelerometer should read 1 00 0 01 The CXM544 magnetometers are calibrated to read directly in Gauss Proper operation of these sensors is difficult to verify without elaborate calibration equipment However verification of operation can be accomplished by pointing each magnetometer sensor into and out of the earth s magnetic field For these orientations the magnetometer should read about 0 5G and 0 5G In the Northern hemisphere the direction of the Doc 7430 0117 01 Rev A Page 15 Crossb w CXM544 User s Manual earth s magnetic field is North with an inclination of about 60 For instance if the system x axis is pointed to magnetic North and inclined about 60 into the earth 30 from vertical the x magnetometer output should read 0 5 Gauss Page 16 Doc 7430
21. ing container s identifying the owner Also indicate the service or repair required the problems encountered and other information considered valuable to the service facility such as the list of information provided to request the RMA number Place the equipment in the original shipping container s making sure there is adequate packing around all sides of the equipment If the original shipping containers were discarded use heavy boxes with adequate padding and protection 8 3 3 X Sealing the Container Seal the shipping container s with heavy tape or metal bands strong enough to handle the weight of the equipment and the container 8 34 X Marking Please write the words FRAGILE DELICATE INSTRUMENT in several places on the outside of the shipping container s In all correspondence please refer to the equipment by the model number the serial number and the RMA number 8 35 Return Shipping Address Use the following address for all returned products Crossbow Technology Inc 4145 N First Street San Jose CA 95134 Attn RMA Number XXXXXX 8 4 Warranty The Crossbow product warranty is one year from date of shipment Doc 7430 0117 01 Rev A Page 29 Crossb w Crossbow Technology Inc 4145N First Street San Jose CA 95134 Phone 408 965 3300 Fax 408 324 4840 Email info xbow com Website www xbow com
22. is looking in the positive x axis direction required to zero the y axis accelerometer output and position the z axis accelerometer so that its output polarity is positive Magnetic roll is defined as the angle of counterclockwise rotation about the x axis looking in the positive x axis direction required to zero the y axis magnetometer output and position the z axis magnetometer so that its output polarity is negative Magnetic roll is useful in defining the CXM544 orientation when inclination is near vertical In this situation gy and g are near zero and roll and azimuth calculations become less accurate 5 3 Definitions Figure 1 and Figure 2 the orientation angles referred to in the following sections for the CXM544 These equations make use of the following definitions x accelerometer x axis output gy accelerometer y axis output Page 18 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w gz accelerometer z axis output Hx magnetometer x axis output Hy magnetometer y axis output H magnetometer z ax s output 5 4 Calculation of Roll and Magnetic Roll The roll angle 0 is determined by using the following equations 0 lt 0 lt 2 n7 cos Sz 2 Ey 8 sin 0 B5 2 2 Ey 8 tang E gt Roll is 0 when g 0 and g gt 0 Roll is 27 radians when g 0 and g lt 0 When the x axis is near vertical pitch lt 5 the quantities g and g become very small and the above expressions yield a les
23. l Port Connections Function 25 pin 9 pin Serial out 2 3 Serial in 3 2 Ground 7 5 Doc 7430 0117 01 Rev A Page 7 Crossb w CXM544 User s Manual Connect the CXM544 serial output line to the computer in line and the CXM544 serial input line to the computer serial out line To communicate with the CXM544 a terminal program will have to be run on the P C The Windows HyperTerminal program will suffice for this Other suitable terminal programs are ProComm and ASCII Pro These programs turn the computer into a dumb terminal In this mode whatever you type on the keyboard goes out the selected serial port e g Com 1 and whatever comes in the serial port is displayed on the computer video display If you use HyperTerminal you must select the proper Com port e g COM 1 COM 2 etc and set the baud rate to be 9600 with one stop bit and no parity Set the port up for direct connect and turn off any handshaking The easiest method of determining if a working communications link with the CXM544 has been established is to observe the PC display when the CXM544 is powered up The CXM544 transmits a power up sign on message which should appear in readable form on the PC display The appearance of an unreadable message at power up may indicate incorrect protocol i e TTL instead of RS232 or an incorrect baud rate 4 2 Operation of the System After establishing communication with the CXM544 data can be obtained
24. mething like this MX 180 0 AX 6451 MY 90 3 AY 4056 MZ 185 6 AZ 1 0001 t 24 3 The numbers following MX MY and MZ represent the system roll inclination and azimuth The numbers following the AX AY and AZ represent the system magnetic roll angle total magnetic field and total gravitational field The total field numbers are of interest because they are the same for all orientations of the sensor since VAX AY AZ 1G VMX MY MZ 1Gauss The degree to which these field magnitudes are constant for different orientations is a measure of the accuracy of the sensor The actual magnetic field amplitude reported will vary somewhat depending on location This value ranges from 0 4 to 0 6 Gauss over the earth s surface It is also possible to configure the system mode to output raw A to D counts This can be accomplished by setting byte 02 0 Doc 7430 0117 01 Rev A Page 9 Crossb w CXM544 User s Manual In order to observe the value of any internal system constant send the commands 0SC02b CR 0SC b CR The first command results in the value of byte constant 02 being transmitted The second command evokes a response containing the values of all byte constants The CXM544 can transmit data in two formats 1 text and 2 binary Text transmissions are formatted to display correctly when the CXM544 is connected to a PC running a terminal emulator program e g PC PLUS HyperTerminal etc Binary t
25. ng bits in the system EEROM See Section 4 5 5 Table 1 Electrical Interface for CXM544 Wire Color Function Red 7 to 12 VDC Black Ground Red White 5 VDC Orange RS232 serial in Yellow RS232 serial out White Orange TTL serial in White Yellow TTL serial out 2 2 Mechanical Features An outline drawing of the CXM544 system is shown in Appendix A The system dimensions are 0 75 x 0 80 x 4 60 1 90 cm x 2 03 cm x 11 68 cm The system is normally mounted by using 4 2 56 x 0 250 long screws to secure the CXM544 reference surface to a flat mating surface Two 0 062 diameter x 0 125 long pins protruding from the external mating surface can be used to orient the CXM544 on the external mounting surface The orientation of the X Y and Z axes 1s shown in 5 2 The output polarity sense of the axes 1s such that a field pointing in the direction of the arrows will produce a positive output voltage For example if the X magnetometer is oriented so the x axis arrow points north then the x axis output voltage Doc 7430 0117 01 Rev A Page 3 Crossb w CXM544 User s Manual will be positive If the x axis accelerometer arrow is pointed down the x axis accelerometer output will be positive 2 3 Communication Interface Two communication protocols are available 1 ASCII 2 BINARY The ASCII protocol is based upon sending ASCII characters to the CXM544 to obtain data The CXM544 responds by sending out an ASCII da
26. or a description of how to decode the binary data packets 4 6 Verifying Proper Operation of the System Proper operation of the CXM544 can be verified when the system is in either angle mode byte 02 03 or sensor mode byte 02 02 Page 14 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w In angle mode proper operation is verified by placing the CXM544 in known orientations and comparing the CXM544 measured data with the known orientation data To check roll and inclination outputs place the CXM544 on a known flat surface with the z axis pointed down A flat surface can be set up and verified by using a bubble level Request data from the CXM544 and verify that the roll and inclination outputs are as follows roll 0 x 0 5 inclination 90 0 5 Next roll the CXM544 about the x axis in increments of 90 and verify that for each position the roll angle increments in succession to 90 180 and 270 while the inclination angle remains 90 0 5 To verify inclination at 0 and 90 position the CXM544 so that the x axis is pointed down 0 inclination and up 180 Because the CXM544 leads exit the bottom of the unit when the x axis is up it may be awkward to verify this orientation without additional support blocks To verify azimuth accuracy a good compass and an area free from magnetic materials must be located Usually areas inside buildings contain some magnetic material e g metal desks rebar
27. r s Manual Crossb w Table 4 CXM544 Binary Data Packet Byte Sensor mode Angle Mode 01 SOT 0x10 SOT 0x10 02 MX MSB Roll Angle MSB 03 MX LSB Roll Angle LSB 04 MY MSB Pitch Angle MSB 05 MY LSB Pitch Angle LSB 06 MZ MSB Azimuth MSB 07 MZ LSB Azimuth LSB 08 AX MSB Magnetic Roll MSB 09 AX LSB Magnetic Roll LSB 10 AY MSB Total Mag Field MSB 11 AY LSB Total Mag Field LSB 12 AZ MSB Total Accel MSB 13 AZ LSB Total Accel LSB 14 Temperature MSB Temperature MSB 15 Temperature LSB Temperature LSB 16 ANA1 MSB ANA1 MSB 17 ANAI LSB ANAI LSB 18 ST ST 19 Checksum Checksum 20 EOT MSB 0x7F EOT MSB 0x7F 21 EOT LSB 0xFF EOT LSB 0xFF Magnetometer and accelerometer sensor values can be decoded by first converting to decimal and then dividing by 10 000 For instance in the above transmission MX OEOE 3598 10 000 0 3598 Gauss MY F646 2490 10 000 0 2490 Gauss AX 0ABA 2740 10 000 0 2740 Gee Angles are decoded by converting to a decimal value and then dividing by 100 If the above data packet was data sent in angle mode you would have MX OEOE 3598 100 35 98 Roll Doc 7430 0117 01 Rev A Page 11 Crossb w CXM544 User s Manual MY F646 2490 100 24 90 Inclination AX 0AB4 2740 100 27 40 Magnetic Roll Total magnetic field and to
28. r leads Applying the wrong power to the Sensor can damage the unit Crossbow is not responsible for resulting damage to the unit 3 8 Setup MagView With the Sensor connected to your PC serial port and powered open the Mag View software 1 From the MagView main display click on Configure button and select the correct COM port Baud Rate default is 9600 and Sensor model 2 You can log data to a file by entering a data file name 3 Youcan also administer various Sensor Settings and Special Settings via this Configure screen and save settings 4 The main screen provides the graphical visualization of various sensor parameters that can be checked from Graph menu 5 The Monitor window allows the user to view the data being sent from the sensor and allows the operator to send commands to the sensor 3 4 Take Measurements Once you have configured MagView to work with your sensor pick what kind of measurement you wish to see AutoData will show you the output you choose as a strip chart type graph of value vs time DataOnce issues the command to send the data one time Monitor window allows the user to view the data being sent from the sensor and allows the operator to send commands to the sensor Page 6 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w 4 System Startup and Checkout 4 1 Initial Setup of the System In order to operate the CXM544 power must be applied to it and an interface wit
29. ransmissions are faster than text transmissions and are more suited to interfacing the CXM544 to a microprocessor sys tem In command mode binary transmissions are initialed by sending a single byte to the CXM544 e g ASCII 128 or ASCII 129 The CXM544 has an autosend mode which enables data to automatically be sent repeatedly upon power up Byte 01 must be set equal to 5A for autosend mode to be active The format of the data sent in autosend mode is determined by the value of byte 08 For repetitive text transmissions set byte 08 10 For repetitive binary transmissions set byte 08 11 4 3 Binary Mode Operation In command mode binary transmissions are initialed by sending a single byte to the CXM544 e g ASCII 128 or ASCII 129 Consider the following data transmissions from a CHS Sensor in Binary mode SOT MX AX MY AY MZ AZTEMP ANAI ST CS EOT 10 OOEE 0AB4 F646 FCIC OEOE 255D 087E 7D01 80 A27FFF The binary data packets will always start with a header byte 0x10 and end with two bytes Ox7FFF The data is always sent most significant byte MSB first then least significant byte LSB Angle sensor and temperature data is sent as 16 bit signed integers The binary data packet is a much more efficient method of sending data In addition binary data is often much easier to parse than ASCII data Table 4 shows the definition of the binary data packet for sensor mode and angle mode Page 10 Doc 7430 0117 01 Rev A CXM544 Use
30. s accurate value of 0 In this situation magnetic roll is often used to determine the angular orientation of the CXM544 about the longitudinal X axis Magnetic roll Om is given by the following 0x0 2 n H sin m H Hj H cosQ i gt Ay H H tang 5 5 Calculation of Inclination Inclination is determined from the following equations 0 n Doc 7430 0117 01 Rev A Page 19 Crossb w CXM544 User s Manual cose 24 8 2 By 8 sin 8 g tane Ex where g dee g g Inclination is 0 when the CXM544 x axis is pointed down and 7 2 radians when horizontal 5 6 Magnetic Heading Azimuth Yaw We first give expressions for the magnetic field in a horizontal reference defined by x1 yl zl where x1 is aligned with the projection of the CXM544 x axis in the horizontal plane and z1 is down li ALIAMINI Hy 2 2 S48 tE H gt 78 Hay 2 2 8 8 H Bags Hyg tHg i g Magnetic heading is then given by 0 lt lt 27 H cos __ ry 2 2 Hg Hy H sin gt Iz 2 2 Ha IH Hy H g Hyg g tan 2 2 Hy H lg 8 H g 2 H g 8 Magnetic heading is 0 when the CXM544 x axis points North and 7 2 radians when it points East Page 20 Doc 7430 0117 01 Rev A Crossb w CXM544 User s Manual 6 Appendix A Mechanical Specifications CXM544 Outline Drawing 6 1 deep 007 0 ajoH
31. should have e 1 CD with MagView Software MagView will allow you to immediately view the outputs of the Sensor on a PC running Microsoft Windows e 1 User s Manual This contains helpful hints on programming installation valuable digital interface information including data packet formats and conversion factors Page 2 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w 2 Electrical and Mechanical Interface 2 1 Electrical Interface The electrical interface to the CXM544 system is shown in Table 1 Seven flying leads 26 gauge Teflon insulated are used to make connection to the system The functions of the out put wires are shown in Table 1 The CXM544 system can be powered either through an internal voltage regulator which converts the input voltage to the 5 volts for internal use or from 5 VDC When the input regulator is used the input voltage can range from 7 to 12V An ideal input voltage which both provides adequate regulation margin and low power consumption is 7 5V The serial communications interface to the CXM544 is provided by the serial in and serial out lines shown in Table 1 An external computer talks to the CXM544 on the serial in line and replies from the CXM544 are transmitted out on the serial out line The serial in and serial out lines operate at TTL or RS232 levels and are normally set to operate at 9600 baud with one stop bit and no parity The user however can change the baud rate by setti
32. ta stream complete with carriage returns and line feeds so that it can be easily displayed on a computer terminal The binary protocol is used for high speed computer to computer interchange In this case one byte is sent to request data e g ASCII 128 The CXM544 then responds with a data packet containing the desired data plus header and checksum The currently supported binary commands and their definitions follow in Table 2 Table 2 Binary Commands for CXM544 Command Command Definition 128 send sensor data in binary format 129 send sensor data in IEEE 32 bit format 131 send angle data in binary format 132 send angle data in IEEE 32 bit format The CXM544 response to these commands is of the following form number of data bytes MX AX MY AY MZ AZ MT lt AT gt 0 data check sum gt lt end gt Refer to the Section 7 1 of this manual Heading Sensor Command Set for a more detailed discussion of the data format for binary transmissions Page 4 Doc 7430 0117 01 Rev A CXM544 User s Manual Crossb w 3 Quick Start 3 1 MagView Software The purpose of the Sensor interface program is to provide a graphical output interface to the CXM544 Orientation Sensor and allow the user to configure and operate the sensor The MagView interface program allows the sensor to be monitored in every mode that the sensor can be programmed The sensor can be programmed to allow
33. tal acceleration are decoded using the same conversion as the normal sensor values divide by 10 000 Temperature is decoded by converting to decimal and dividing by 100 TEMP 087E 2174 100 21 74 C The ANAI transmission voltage and ST Status bytes are not typically used in the CHS Sensor The value of these bytes will have no meaning The CS byte is a checksum The checksum is calculated by summing all of the bytes in the transmission before the CS byte excluding the SOT and status ST characters For the above transmission the checksum is calculated as follows CS 00 EE 0A B4 F6 46 FC 1C 0E 0E 25 5D 08 7E 7D 01 05A2 The checksum is the lower byte of the sum or A2 4 4 Descriptions of the System Internal Constants The CXM544 employs two types of internal constants 1 byte and 2 floating There are approximately 43 byte constants which are used to configure the operating characteristics of the CXM544 The most important of these constants and their functions are provided in Table 5 Detailed descriptions of all the internal byte constants can be found in the Appendix B of this manual Table 5 Byte Description Byte Function 00 enables echoing when non zero 01 enables autosend when 5A 02 enables sensor A D count output when 0 sensor output when 02 and angle output when 03 08 Sets power on mode e g 710 enables autosend in ASCII mode on power on 09 Baud rate lock 5A
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