MT Low-Level Communication Protocol Documentation
Contents
1. PARAM VALUE Description 0 SyncOut mode 2 bytes Bit 3 0 0000 SyncOut mode disabled default 0001 Toggle mode 0010 Pulse mode Bit 4 Polarity 0 Negative pulse 1 Positive pulse Bit 15 5 Reserved VALUE Skip factor An unsigned 16 bit value that defines how many times the internal sampling instance should be skipped before changing the SyncOut pin state The internal trigger instance is based on the sampling period set by SetPeriod PARAM VALUE Description 1 Skip factor 2 bytes Bit 15 0 Skip factor value VALUE Offset An unsigned 32 bit value that defines the number of clock ticks to delay the SyncOut state change after the internal sampling instance One clock tick is equal to 1 29 4912 MHz 33 9ns PARAM VALUE Description 2 Offset 4 bytes Bit 31 0 Offset value Valid value is 0 513 0Ox00000201 and higher VALUE Pulse width An unsigned 32 bit value that defines the pulse width when SyncOut mode is set to Pulse mode The pulse width is specified in ticks and one tick is equal to 1 29 4912 MHz 33 9ns PARAM VALUE Description 3 Pulse width 4 bytes Bit 31 0 Pulse width value Valid value is 0 1700 OxOO0006A4 and higher Document MT0O101P K Xsens Technologies B V 18 MT Low Level Communication Protocol Documentation XSens 4 3 5 Configuration messages ReqConfiguration MID 12 Ox0C DATA n a Direction To MT Valid in Config State Request the configuration settings of the de2. Section 4 3 6 Message ReqData MTData XKF Filter messages Section 4 3 7 Message ReqHeading ReqHeadingAck SetHeading SetHeadingAck ResetOrientation ResetOrientationAck ReqUTCTime UTCTime ReqAvailableScenarios AvailableScenarios ReqCurrentScenario ReqCurrentScenarioAck SetCurrentScenario SetCurrentScenarioAck ReqGravityMagnitude ReqGravityMagnitudeAck SetGravityMagnitude SetGravityMagnitudeAck ReqleverArmGPS ReqleverArmGPSAck SetleverArmGPS MID 52 0x34 50 0x32 MID 130 0x82 131 0x83 130 0x82 131 0x83 164 OxA4 165 0xA5 96 0x60 97 Ox61 98 0x62 99 0x63 100 0x64 101 0x65 100 0x64 101 0x65 102 0x66 103 0x67 102 0x66 103 0x67 104 0x68 105 0x69 104 0x68 To MT To host To MT To host To MT To host To MT To host To MT To host To MT To host To MT To host Direction To MT To host Direction To MT To host To MT To host To MT To host To MT To host To MT To host To MT To host To MT To host To MT To host To MT To host To MT To host To MT XSens Host sets OutputSkipFactor Device acknowledges message Request object alignment matrix Device returns object alignment matrix To set the object alignment matrix Device acknowledges SetObjectAlignment message Request current output mode Device returns output mode Host sets output mode Device acknowledges SetOutputMode message Request current output settings Device r
3. Valid in Config State Request one of the current Syncin settings of the device i e mode skip factor or offset The requested setting is specified by the PARAM value See SetSyncInSettings for description of the data field of the received acknowledge PARAM PARAM defines which of the Syncin settings should be returned by the acknowledge message See following table PARAM value Setting 0 0x00 Syncin mode 1 0x01 Skip factor 2 0x02 Offset SetSyncInSettings MID 214 OxD6 DATA PARAM VALUE 1 N bytes Direction To MT Valid in Config State Set a Syncin setting defined by the PARAM field with the value specified with the VALUE field Use Syncin to synchronize the MT with external hardware Both the MTi standard version and MTx have an input pin that can be connected to other hardware like a high precision clock generator See MTi and MTx User Manual MTi_MTx for important information about triggering and synchronization NOTE The MTi G does not support SyncIN The MTIi G is synced to UTC when a GPS fix is available PARAM The PARAM value 1 byte indicates which Syncln setting will be set The VALUE field which can be either two or four bytes long defines the new value of the setting See table for the different PARAM values PARAM value Setting 0 0x00 Syncin mode 1 0x01 Skip factor 2 0x02 Offset Document MT0O101P K Xsens Technologies B V 15 MT Low Level Communication Protocol Documentation XS
4. Valid in Config State Request the current error mode see SetErrorMode for information about data field of received acknowledge SetErrorMode MID 218 OxDA DATA ERRORMODE 2 bytes Direction To MT Valid in Config State Set the error mode to a specific ERRORMODE ERRORMODE The ERRORMODE is an unsigned 16 bit value that defines how the device should deal with errors that are not message related The default error mode is that in case the sampling instance is missed the sample counter is increase and no further action is taken ERRORMODE 1 ERRORMODE Description O 0x0000 Ignore any errors except message handling errors 1 Ox0001 In case of missing sampling instance increase sample counter and do NOT send error message 2 Ox0002 In case of missing sampling instance increase sample counter and DO send error message 3 Ox0003 In case of non message handling error an error message is sent and the device will enter the Config State ReqLocationID MID 132 0x84 DATA n a Direction To MT Valid in Config State Request location ID see SetLocationID for information about data field of received acknowledge message SetLocationID MID 132 0x84 DATA LOCID 2 bytes Direction To MT Valid in Config State Set a user defined value This value can be used to give the device a location dependant identifier or any arbitrary user value LOCID Document MT0101P K Xsens Technologies B V 13 MT Low Level Communicati
5. contains the relevant information which with the data received by the host in Measurement State can be unambiguously interpreted When logging MTData messages it is advisable to include the Configuration message in the data header for future analysis or post processing If the host does not respond to the WakeUp message at power up or after issuing a Reset message the MT will automatically enter the Measurement State Just before entering the state it will send the Configuration message The configuration settings are all read from the non volatile memory and are used during the measurement The default configuration of the MT is shown in the next table Property Value Output mode Orientation output Output settings Orientation in quaternion mode Sample counter enabled Sample frequency 100 Hz Output skip factor In Measurement State is normally not used to change any settings To change settings the device must enter the Config State for which the user must first send the GoToConfig message See Section 4 for more information about messages If the output mode is set to un calibrated raw data an additional message with the calibration parameters eMTS is sent after the Configuration message Document MT0O101P K Xsens Technologies B V A MT Low Level Communication Protocol Documentation 4 Messages 4 1 Message structure The communication with the MT is done by messages which are built according to a standard stru
6. B TYPE 0 22 index VERSION 1 22 index LABEL 2 22 index ReqCurrentScenario Direction To MT MID 100 0x64 all 5 available scenarios When less than 5 scenarios are available the O Description Scenario type Scenario version Scenario label The label is NOT 0 terminated and it is padded to 20 bytes with spaces Requests the ID of the currently used scenario NOTE For MTi and MTx this is not supported in firmware version 2 0 and lower SetCurrentScenario Direction To MT MID 100 0x64 DATA SCENARIO 2 bytes Sets the scenario to use For more information about the various scenarios please refer to the XKF Scenarios sections in the device specific manuals MTi_MTx and MTi G NOTE For MTi and MTx this is not supported in firmware version 2 0 and lower SCENARIO Hardware Type MTi G MTi G MTi G MTi MTx MTi MTx MTi MTx MTi MTx NO UB D M ta Description General Automotive Aerospace Human Human_large_ accelerations Machine Machine_nomagfield Document MT0101P K Xsens Technologies B V 31 MT Low Level Communication Protocol Documentation XSens 8 MTi MTx Marine 9 MTi G General_nobaro 10 MTi G Aerospace_nobaro 11 MTi G Automotive_nobaro 17 MTi G Marine ReqCurrentScenarioAck Direction To host MID 101 0x65 DATA SCENARIO VERSION Contains the currently used scenario NOTE For MTi and MTx this is not supported in firmware version 2 0 and lower DA
7. Changed Raw GPS gt GPS PVT New corporate design 2005 2009 Xsens Technologies B V All rights reserved Information in this document is subject to change without notice Xsens is a registered trademark of Xsens Technologies B V MTi and MTx are trademarks of Xsens Technologies B V Document MT0101P K Xsens Technologies B V MT Low Level Communication Protocol Documentation XSens Table of Contents 1 TERMS ABBREVIATIONS AND REFERENCES eesossesessesossesossesossosossossesossesossossesosoosoesosossossesossossesossos 1 2 INTRODUC TION E 2 3 STATE See E E E 3 sL LON TATE E E A eco ueaeenceaces ee tastendsbeueccamecaneren 3 Ge MEASUREMENT OTA TE EE 4 4 ME SAGE Sor R a 5 w MESSAGE STRUCTURE arrine ar AAAA E OTERO ONE 5 A MESSAGE USACE oora E N E EE 6 A TR RENE 8 4 3 1 WakeUp E e 8 4 3 2 Informational ee e 8 4 3 3 Device specific MeSSages secayscnscecpsssiiocarvavicaipsannvunaieaupsnstiocasintioumpcanianstiesampan sib aayinueeaansaseieateenmpnestooanyes 12 BSA SVNACHTONIZATON CSS QOS oa secccsvececcaeecoreeatieacesaivensiiecussaressciorasieadeasveans peau gn EE EESE OETA E 15 4 3 5 Con guration MESS AgES eee nan eae ATN TA EEA OEA ETETE EO 19 ASO E et e 26 BDF d ETC 30 5 MT LOW LEVEL COMMUNICATION PROTOCOL EXAMPLE csccscscscsccscscscsccccscscncscscsssscscscesecssoues 36 6 MISCELLANEOUS E 38 Ged IDE EECHER 38 EE 39 7 MESSAGE REFERENCE LISTING eege 40 Document MT0O101P K Xsens Tech
8. Direction To MT Valid in Config State Sets the sampling period of the device used in Measurement State PERIOD PERIOD is an unsigned 16 bit value indicating the length of the period Resolution is in 1 115200 seconds i e 8 68 us The following table shows the default minimum and maximum values PERIOD Value Sampling period freq Default 1152 Ox0480 10 0ms 100Hz Minimum 225 OxOOE1 1 95ms 512Hz Maximum 1152 0x0480 10 0ms 100Hz The MT outputs the MTData at a rate that is not only depending on the sampling frequency but also on the OutputSkipfactor see SetOutputSkipfactor Normally this factor is zero and the MTData message is sent 1 sampling period times per second A value higher than zero corresponds to how many times the MTData message is NOT sent to the host To calculate how often the MTData is sent to the host use the following formula MTData frequency Hz 115200 PERIOD OutputSkipfactor 1 The MT sample frequencies lower than 100Hz are not settable directly By default the device uses 100Hz as lowest sampling frequency However in combination with the OutputSkipfactor see SetOutputSkipfactor message lower frequencies can be set For example if SetPeriod is sent with a sampling period of 20ms 50Hz the device will automatically set the sampling period to 10ms 100Hz and the OutputSkipfactor to 1 The resulting sampling period is 10ms OutputSkipfactor 1 20ms 50Hz If the sampling
9. GPS 1PPS pulse The data age of GPS data can be calculated based on elapsed number of samples since the last 1PPS pulse Sacc bGPS a5 P U1 Unsigned Char U2 Unsigned 16 bit integer U4 Unsigned 32 bit integer I2 Two s complement 16 bit integer 14 Two s complement 32 bit integer Temperature data output mode 4 bytes Contains the internal temperature of the sensor in degrees Celsius float value Calibrated data output mode 36 bytes Document MT0O101P K Xsens Technologies B V 27 MT Low Level Communication Protocol Documentation XSens Contains the calibrated data output of the accelerations rate of turn and magnetic field in X Y and Z axes in floats Orientation data output mode quaternion 16 bytes Contains the q0 q1 q2 and q3 quaternions in floats that represent the orientation of the MT Orientation data output mode Euler angles 12 bytes Contains the three Euler angles in floats that represent the orientation of the MT Orientation data output mode Matrix 36 bytes Contains the rotation matrix DCM in floats that represents the orientation of the MT See MTi and MTx User Manual MTi_MTx or MTi G User Manual MTi G for the interpretation of the data values Auxiliary data output mode 4 bytes Auxiliary data consists of both analogIN 1 and 2 data This is the sampled value of the analog input 1 and 2 The data format is two 16 bit unsig
10. MID Message ID of the acknowledge message is increased by one in comparison with the sending message ReqDID Some messages have the same MID and depending on whether or not the message contains the data field the meaning differs This is the case with all the messages that refer to changeable settings For example the MID Document MT0O101P K Xsens Technologies B V 6 MT Low Level Communication Protocol Documentation XSens of message requesting the output mode ReqOutputMode is the same as the message that sets the output mode SetOutputMode The difference between the two messages is that the Length field of ReqOutputMode is zero and non zero for SetOutputMode Example Request current output mode Sending message ReqOutputMode OxFA OxFF OxDO 0x00 0x31 hexadecimal values Receiving message Acknowledge ReqOutputModeAck OxFA OxFF OxD1 0x02 MH ML CS hexadecimal values ReqOutputModeAck contains data which represents the current mode MH amp ML CS stands for the checksum value To change the output mode you must add the new mode in the data field of the sending message Set the output mode Sending message SetOutputMode OxFA OxFF OxDO 0x02 MH ML CS hexadecimal values Receiving message Acknowledge SetOutputModeAck OxFA OxFF OxD1 0x00 0x30 hexadecimal values Document MT0O101P K Xsens Technologies B V 7 MT Low Level Communication Protocol Documentation XSens 4 3 Message lis
11. Xsens range of miniature MEMS based inertial Motion Trackers the MTi G the MTi and the MTx These Motion Trackers or MTs all use a common binary communication protocol called the MT Communication Protocol Knowledge of this protocol is important if you wish to directly communicate to an MT on low level basis using the RS 232 RS 485 or RS 422 interfaces The MT communication protocol based message enables the user to change the configuration of the MT G MTi and MTx and retrieve the output data NOTE The MTIi G is the most advanced member of the MT family and some messages are not supported by the MTi and Mix Also some specific messages or settings are not relevant and or supported by the MTi G Where a specific type of MT is not supported it is clearly indicated The communication protocol used for the MTs is compliant to the MotionTracker communication protocol This document fully documents this standard message based protocol developed by Xsens for use of inertial sensors The configuration settings are all user settable using the communication protocol Examples are sample frequency in and output synchronization baudrate and output modes The different output modes enable the user to change the output data to the one that is preferred Configuration changes are executed in the so called Config State In this state the MT accepts messages that set the output mode or other settings Whenever the preferred configuration is s
12. of the WakeUp message the MT enters the Config State Prior to entering the Measurement State the Configuration message is always sent to the host This is the configuration that is read from the internal non volatile memory and will be used in the Measurement State The data in the Configuration message can always be used to determine the output mode and settings Another way to enter the Config or Measurement State is to use the GoToConfig or GoToMeasurement messages while the other state is active WakeUp procedure WakeUpAck received by device No WakeUpAck received by device GotoMeasurement Measurement GotoConfig 3 1 Config State Config State is used to get and or set various settings of the MT Most of the settings will change the configuration which defines the device functionality in Measurement State Settings that change the configuration are for example the communication baudrate sample period output mode output settings or synchronization properties At power up all settings are read from non volatile memory All settings are stored in a format developed by Xsens known as the eMTS extended Motion Tracker Specification along with other device specific data such t If the device is set to RAW OutputMode the device will send additional encrypted data to the host after sending the Configuration message The encrypted data primarily contains the calibration values of the device This data is referre
13. period can not be made OutputSkipfactor is not an integer an error message will be returned In this case choose a lower sampling period with an integer OutputSkipfactor to generate the requested frequency For example to have a resulting sampling period of 13 33ms 75Hz set the sampling period to 6 67ms 150Hz and the OutputSkipfactor to 1 The maximum value defined for PERIOD The actual data output frequency can be set lower than 100Hz in combination with the OutputSkipFactor See text Document MT0101P K Xsens Technologies B V 20 MT Low Level Communication Protocol Documentation XSens NOTE The baudrate may limit the sample frequency that can be used for a specific output mode and output setting due to the amount of data that must be transmitted throughput please refer to the device specific manuals MTi_MTx and MTi G for further details ReqOutputSkipFactor MID 212 OxD4 DATA n a Direction To MT Valid in Config State Request how many times the data output is skipped before sending the data in the MTData message to host For information about data field of received acknowledge see SetOutputSkipFactor SetOutputSkipfactor MID 212 OxD4 DATA SKIPFACTOR 2 bytes Direction To MT Valid in Config State Set the output skip factor SKIPFACTOR The skip factor is an unsigned 16 bit value and is by default zero The value represents how many times the data output is skipped running at the current sampli
14. 0 F1 The MT acknowledges with RX FA FF 11 00 FO Start logging data The MT sends the MTData message which has the following format RX FA FF 32 4A AccData GyrData MagData MatrixData SC CS The AccData GyrData MagData fields contain 3x 4 bytes that are single precision float values for the X Y and Z axis SC stands for sample counter and is a 2 byte unsigned value and CS is the checksum Document MT0O101P K Xsens Technologies B V 37 MT Low Level Communication Protocol Documentation 6 Miscellaneous 6 1 Default factory settings The default settings of the MT will set the device in a configuration that calculates and outputs the orientation 100 times per second in quaternions The MTData message will also include a sample counter which can be used to detect missing samples The data is transmitted at a baudrate of 115k2 bits per second and the synchronization in and outputs are disabled The default settings and the messages to change the specific setting are listed in the following table Property Default value Message section nr SetOutputMode 4 3 5 Output settings Orientation in quaternion mode SetOutputSettings 4 3 5 Sample counter Output skip fator o setoutputSkipfactor 435 There are two ways to set the MT in this default setting You can RestoreFactoryDef or you can use the individual messages shown in the table to re set the settings Keep in mind that if you use the RestoreFactoryDef message the fil
15. 304101418 237 gt COM 59 5 FA FF 31 00 DO J02 gt COM 59 7 FA 01 05 02 04 80 74 22 gt COM 59 6 FA 01 19 01 02 E3 515 gt COM 59 8 FA 01 13 03 02 00 04 E3 lt 20080304101505 217 gt COM 59 5 FA 01 05 00 FA 20080304101800 105 gt COM 59 5 FA FF 11 00 FO 200803041018 36 gt COM 59 23 FA FF 32 12 3F 21 OB D2 3C 9B 42 15 BC 7C D2 8B 3F 46 E6 40 01 5C BS Data packet 1025 times M 59 Goto Config Acknowledge 20080304101430 002 gt COM 59 Request Period Acknowledge 1152 100 Hz Request Baudrate Acknowledge 115200 Firmware Revision 2 0 4 9 Set Period Acknowledge 105 gt COM 59 Goto Measurement Acknowledge 5 gt COM 59 Data packet 349 times Before you can change any settings make sure Config is active IA PA FF 30 00 D1 Continue receiving data until the following bytes are received RX FA FF 31 00 DO Set the Output mode to calibration orientation data TX FA FF DO 02 00 06 29 The MT acknowledges with RX FA FF D1 00 30 Set the Output setting to matrix orientation output sample counter TX FA FF D2 04 00 00 00 09 22 The MT acknowledges with RX FA FF D3 00 2E Set the sample period to 1 120 sec 120Hz Document MT0O101P K Xsens Technologies B V 36 MT Low Level Communication Protocol Documentation IA PA FF 04 02 03 CO 38 The MT acknowledges with RX FA FF 05 00 FC Goto measurement state to start logging data IA PA FF 10 0
16. Direction To host Valid in Config State Acknowledge of ReqFWRev message Data field contains firmware code major minor revision part ReqDataLength MID 10 Ox0a DATA n a Direction To MT Valid in Config State Request the length of the data field of the MTData message based on the current configuration The device acknowledges with the DataLength message DataLength MID 11 OxOb DATA DATALENGTH 2 bytes Direction To host Valid in Config State Acknowledge of ReqDataLength message The data field contains DATALENGTH an unsigned 16 bits value that is equal to the data length of the MTData message send in Measurement State based on the current configuration Error MID 66 0x42 DATA ERRORCODE 1 byte Direction To host Valid in Config and Measurement State Indicate that an error has occurred Error type is specified in the ERROR field ERRORCODE A one byte value indicating the type of error See table ERRORCODE Error description 3 0x03 Period sent is not within valid range Document MT0O101P K Xsens Technologies B V 10 MT Low Level Communication Protocol Documentation ReqGPSStatus MID DATA Direction Valid in 4 0x04 30 Ox1E 32 0x20 33 0x21 166 OxA6 n a To MTi G Config State NOTE Only supported by MTi G XSens Message sent is invalid Timer overflow this can be caused to high sample frequency or sending to much data to MT during measurement Baudrate sent is not within valid
17. ErrorModeAck 219 OxDB To host Device acknowledges SetErrorMode message ReqLocationID 132 0x84 ToMT Request location ID ReqLocationIDAck 133 0x85 To host Device returns location ID SetLocation ID 132 0x84 To MT Host sets location ID SetLocationIDAck 133 0x85 To host Device acknowledges SetLocationID message RestoreFactoryDef 14 OxOE To MT Restore factory defaults RestoreFactoryDefAck 15 OxOF To host Device acknowledges RestoreFactoryDef message ReqTransmitDelay 220 OxDC To MT Requests delay value which equals the minimum time between last byte reception and transmission start of acknowledge in RS485 mode ReqTransmitDelayAck 221 0xDD To host Device returns delay value SetTransmitDelay 220 OxDC To MT Host sets delay value SetTransmitDelayAck 221 O0xDD To host Device acknowledges SetTransmitDelay message StorexXkfState 138 Ox8A To host Stores state of XKF in non volatile memory of device Synchronization messages Section 4 3 4 Message MID Direction Description ReqSynclinSettings 214 OxD6 To MT Request a Syncln setting of the device i e Syncin mode skip factor or offset ReqSynclinSettingsAck 215 OxD7 To host Device returns Syncin setting SetSynclinSettings 214 OxD6 To MT Host sets a Syncin setting SetSyncInSettingsAck 215 OxD7 To host Device acknowledges SetSyncinSettings message ReqSyncOutSettings 216 OxD8 To MTi Request a SyncOut setting of the device i e SyncOut mode skip factor offset or pulse width ReqSyncOutS
18. H IDHL IDLH IDLL 4 bytes Direction To host Valid in Config State Acknowledge of ReqDID message Data field contains device ID serial number InitMT InitBus MID 2 0x02 DATA n a Direction To MT Valid in Config State This message is supported so the host can use the same message for MT as for the XbusMaster The device will answer with the InitMTResults message For the MT it has the same functionality as ReqDID InitMTResults InitBusResults MID 3 0x03 DATA IDHH IDHL IDLH IDLL 4 bytes Direction To host Valid in Config State Acknowledge of InitMT message Data field contains device ID serial number and corresponds to the S N number on the bottom of the device hexadecimal values ReqProductCode MID 28 Ox1c DATA n a Direction To MT Valid in Config State Request to send the product code MT acknowledges by sending the ProductCode message ProductCode MID 29 Ox1d DATA PRODUCT CODE max 20 bytes Direction To host Valid in Config State Acknowledge of ReqProductCode message Data field contains the product code string in ASCII format e g MTi 28A33G85 Document MT0O101P K Xsens Technologies B V 9 MT Low Level Communication Protocol Documentation XSens ReqFWRev MID 18 0x12 DATA n a Direction To MT Valid in Config State Request to send the firmware revision of the device MT acknowledges by sending FirmwareRev message FirmwareRev MID 19 0x13 DATA MAJOR MINOR REV 3 bytes
19. Low Level Communication Protocol Documentation XSens 4 3 3 Device specific messages ReqBaudrate MID 24 0x18 DATA n a Direction To MT Valid in Config State Request the baudrate of the device See SetBaudrate for data field description of the received acknowledge SetBaudrate MID 24 0x18 DATA BAUDRATE 1 byte Direction To MT Valid in Config State This message changes the baudrate of the communication interface RS 232 or RS 422 The new baudrate will be stored in non volatile memory and will become active after issuing the Reset message or power cycle BAUDRATE See table for the different baudrates and the corresponding value of BAUDRATE NOTE The baudrate may limit the sample frequency that can be used for a specific output mode and output setting due to the amount of data that must be transmitted throughput please refer to the device specific manuals MTi_MTx and MTi G for further details The default baudrate is 115k2 bps Baudrate settings 921k6 OxOA and 4k8 are only available for firmware versions higher than 2 4 8 Baudrate bps BAUDRATE 921k6 128 0x80 921k6 alternative 10 Ox0A 460k8 O 0x00 230k4 1 0x01 115k2 2 0x02 57k6 4 0x04 38k4 5 0x05 28k8 6 0x06 19k2 7 0x07 14k4 8 0x08 9k6 9 0x09 4k8 11 0x0B Document MT0101P K Xsens Technologies B V 12 MT Low Level Communication Protocol Documentation XSens ReqErrorMode MID 218 OxDA DATA n a Direction To MT
20. MT Low Level Communication Protocol Documentation Document MT0101P Revision K 27 May 2009 Xsens Technologies B V phone 31 88 97367 00 fax 31 88 97367 01 email info xsens com internet www xsens com Revisions SN e n a June 3 2005 B July 4 2005 C August 5 2005 D September 8 2005 E March 2 2006 F September 20 2006 G October 30 2007 H April 1 2008 August 8 2008 J October 19 2008 K May 27 2009 SSM SSM SSM SSM SSM PRI MMI MMII RZA JPM MMI PRI PRI MHA First version Added examples Xbus class raw data Changed maximum sample period Added Miscellaneous Section Added info about Synclin offset Update Xbus class example code for Xbus class version 1 1 Added message ReqProductCode ProductCode Added message Req Set ExtOutput for analog outputs Changed name Xbus class to MTComm Update incorrect maximum value of SetTransmitDelay Updated Output mode amp settings for temperature amp auxiliary outputs Added Req SetObjectAlignment messages Updated for MTi G MTi G specific messages XKF Scenario messages Updated regarding firmware version 2 1 Textual correction w r t SetOutputSettings table Output format corrections and clarification Added detailed information about the status byte Small textuals changes Added Req Set ProcessingFlags and SetNoRotation messages Added scenario numbering Added baud rates StoreXxKFstate 12 20 calculation
21. TA B Description SCENARIO 0 Scenario type VERSION 1 Scenario version ReqGravityMagnitude Direction To MT MID 102 0x66 Requests the magnitude of the gravity that is used in XKF see SetGravityMagnitude for information about data field of received acknowledge NOTE For MTi and MTx this is not supported in firmware version 2 0 and lower SetGravityMagnitude Direction To MT MID 102 Ox66 DATA GRAVITY float Sets the magnitude of the gravity that is used in XKF NOTE For MTi and MTx this is not supported in firmware version 2 0 and lower ReqProcessingFlags Direction To MT MID 32 0x20 Requests the processing flags that are used in XKF see SetProcessingFlags for information about data field of received acknowledge NOTE For MTi and MTx this is not supported in firmware version 2 2 and lower Document MT0O101P K Xsens Technologies B V 32 MT Low Level Communication Protocol Documentation XSens SetProcessingFlags Direction To MT MID 32 0x20 DATA PROCESSING FLAGS Sets the processing flags that are used in XKF NOTE For MTi and MTx this is not supported in firmware version 2 2 and lower PROCESSING FLAGS bits Processing Flag Initialization Gyroscope Bias Estimation On Off Automatic No Rotation assumption after filter reset and or power on to Bit O quickly estimate rate gyroscope bias Refer to section 3 3 in User Manual Refer also to the SetNoRotation message on page 34 DEFA
22. Ti G for further details Document MT0O101P K Xsens Technologies B V 22 MT Low Level Communication Protocol Documentation 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MODE bits Output mode Bit O Temperature data Bit 1 Calibrated data Bit 2 Orientation data Bit 3 Auxiliary data Bit 4 Position data Bit 5 Velocity data Bit 11 Status data Bit 12 GPS PVT data Position Velocity Time and barometric pressure Bit 14 RAW inertial data 16 bit ADC values Can only be combined with GPS PVT data ReqOutputSettings MID 210 OxD2 DATA n a Direction To MT Valid in Config State Requests the current output settings See SetOutputSettings for information about data field of received acknowledge Document MT0101P K Xsens Technologies B V 23 MT Low Level Communication Protocol Documentation XSens SetOutputSettings MID 210 OxD2 DATA SETTINGS 4 bytes Direction To MT Valid in Config State Sets the output settings of the MT NOTE The baudrate may limit the sample frequency that can be used for a specific output mode and output setting due to the amount of data that must be transmitted throughput please refer to the device specific manuals MTi_MTx and MTi G for further details SETTINGS 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 121110 9 8 7 6 5 4 3 2 1 0 SETTINGS bits Settings Bit 1 0 Timestamp output 00 No timestamp 01 Sample Counter 10 UTC Time 11 Sample Counter UTC T
23. ULT off Fixed Gravity On Off XKF can either calculate the local gravity from the GPS LatLonAlt or use a Bit 1 fixed gravity set by the SetGravityMagnitude message DEFAULT off ReqleverArmGps Direction To MT MID 104 0x68 Requests the lever arm of the GPS antenna with respect to the MTi G in OBJECT coordinates NOTE Only supported by MTi G SetLeverArmGps Direction To MT MID 104 0x68 DATA ARM 3x float Sets the lever arm of the GPS antenna with respect to the MTi G in OBJECT coordinates NOTE Only supported by MTi G ReqLeverArmGpsAck Direction To host MID 105 0x69 DATA ARM 3x float DATA Contains the lever arm of the GPS antenna with respect to the MTi G in OBJECT coordinates Document MTO101P K Xsens Technologies B V 33 MT Low Level Communication Protocol Documentation XSens NOTE Only supported by MTi G ResetOrientation MID 164 OxA4 DATA CODE 2 bytes Direction To MT Valid in Config State and Measurement State Reset the orientation Different resets are supported see next table For more information about the different resets see MTi and MTx User Manual MTi_MTx or MTi G User Manual MTi G To store the new orientation goto Config state and send the ResetOrientation message again but now with CODE Ox0000 If the orientation is not stored the next time the Measurement State becomes active the reset orientation results are discarded CODE A two byte value indicating which
24. cture The message has two structures one with a standard length and one with extended length The standard length message has a maximum of 254 data bytes and is used most frequently In some cases the extended length message needs to be used if the number of data bytes exceeds 254 bytes An MTComm message standard length contains the following fields An MTComm message extended length contains these fields PREAMBLE BD MD LEN EXT LEN DATA CHECKSUM Field Field width Description Indicator of start of packet gt 250 OxFA BID A byte Bus identifier or Address gt 255 OxFF Message identifier LEN 1 byte For standard length message Value equals number of bytes in DATA field Maximum value is 254 OxFE For extended length message Field value is always 255 OxFF 16 bit value representing the number of data bytes for extended length messages Maximum value is 2048 Ox0800 standard length extended length bytes Checksum of message Preamble Every message starts with the preamble This field always contains the value 250 OxFA BID or Address The BID bus ID address field is included in the message format to be compatible with the XbusMaster which connects to multiple MotionTrackers A stand alone MT i e not connected on an Xbus has a BID value of 1 0x01 indicating first device A stand alone MT device is however also a master device on its own bus and it can therefore also be address
25. d to as the eMTS data extended Motion Tracker Specification data This data is required to be able to later process the data using Xsens software to calculate calibrated inertial data values as well as estimating orientation etc Document MT0O101P K Xsens Technologies B V 3 MT Low Level Communication Protocol Documentation XSens as calibration parameters The format is proprietary but all settings can be manipulated by using the appropriate Set messages Settings changed in Config State are immediately stored in the memory and will retain their latest values even if the device is disconnected from power Some messages have an additional parameter that requires the user to expressly specify whether or not the new values should be stored in non volatile memory Either way the setting changes are immediate NOTE There is one exception namely the baudrate setting The new setting will not be used immediately it will be used at the next power cycle or after a soft reset See Section 4 for more information about messages 3 2 Measurement State In Measurement State the MT will output its data to the host in a way depending on the configuration settings defined in Config State A single message MTData is used for all different output modes It is therefore important that the host knows how the device is configured The current configuration will determine how the message data must be interpreted A special message Configuration
26. ed using the BID value 255 OxFF indicating a master device An MT will only acknowledge a message reply if it is addressed with a valid BID An MT will always acknowledge a message with the same BID that has been used to address it For example this means that the Document MT0O101P K Xsens Technologies B V 5 MT Low Level Communication Protocol Documentation XSens same device can be addressed using a BID of 255 OxFF as well as 1 0x01 and it will reply appropriately with the corresponding BID Note however that messages generated by the MT itself i e not in acknowledge on a request will always have a BID of 255 OxFF In practice the only message for which this occurs is the MTData message Message Identifier MID This message field identifies the kind of message For a complete listing of all possible messages see section 4 Length LEN Specifies the number of data bytes in the DATA field for standard length message If value 255 OxFF is specified the message will be interpreted as an extended message length and the next two bytes are used for the number of bytes in the DATA field If zero no DATA field exists Extended Length EXT LEN This field is a 16 bit value representing the number of data bytes in the DATA field of an extended length message Data DATA This field contains the data bytes and it has a variable length which is specified in the Length or Extended Length field The interpretatio
27. ens VALUE Syncin mode Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 PARAM VALUE Description 0 Syncin mode 2 bytes Bit 1 0 Trigger mode NOT valid for MTi G 00 Syncin mode disabled default 01 Rising Edge 10 Falling Edge 11 Reserved Bit 3 2 Trigger type NOT valid for MTi G 00 ADC sampling incl sending of MTData 01 Sending of latest output data Bit 15 4 Reserved VALUE Skip factor An unsigned 16 bit value that defines how many times the trigger should be skipped before actually trigger the device PARAM VALUE Description 1 Skip factor 2 bytes Bit 15 0 Skip factor value VALUE Offset By default the time between a valid trigger and actual sampling of the internal sensors is 20 2us An additional offset can be set to increase this time The offset value is an unsigned 32 bit value that defines the number of clock ticks to delay the sampling One clock tick is equal to 1 29 4912 MHz 33 9ns PARAM VALUE Description 2 Offset 4 bytes Bit 31 0 Offset value Valid value is 0 264 Ox00000108 and higher Document MT0101P K Xsens Technologies B V 16 MT Low Level Communication Protocol Documentation ReqSyncOutSettings MID 216 OxD8 DATA PARAM 1 byte Direction To MTi Valid in Config State XSens Request one of the current SyncOut settings of the MTi i e SyncOut mode skip factor offset or pulse width The requested setting is specified by the PARAM value See SetSyncOutSettings
28. es SetMagnetic Declination ReqProcessingFlags 32 0x20 To MT Request filter processing flags ReqProcessingFlagsAck 33 0x21 To host Device returns processing flags SetProcessingFlags 32 0x20 To MT Host sets processing flags SetProcessingFlagsAck 33 0x21 To host Device acknowledges SetProcessing Flags SetNoRotation 34 0x22 To MT Initiates XKF3 no rotation update procedure SetNoRotationAck 35 0x23 To host Device acknowledges SetNoRotation message Document MT0O101P K Xsens Technologies B V 43 MT Low Level Communication Protocol Documentation
29. essage at power up or reset If received within 500ms after WakeUp device enters Config State else Measurement State Device enters config state Device acknowledges GoToConfig message Device enters measurement state Device acknowledges GoToMeasurement message Reset device Acknowledgement of Reset message Description Host request device ID of the device Device acknowledges request by sending its ID Request device ID of the device for compatibility of Xbus Master users Same as DevicelD message Host request product code of the device Device acknowledges request by sending its product code Host requests firmware revision of device Device acknowledges request by sending its firmware revision Request the number of data bytes in MTData message Contains the number of data bytes of the MTData message Error message Request GPS Status Device returns GPS Status Description Requests current baudrate of the serial communication ReqBaudrateAck 25 0x19 To host Device returns baudrate of serial communication SetBaudrate 24 0x18 ToMT Host sets baudrate of serial communication Document MT0O101P K Xsens Technologies B V AO MT Low Level Communication Protocol Documentation XSens SetBaudrateAck 25 0x19 To host Device acknowledges SetBaudrate message ReqErrorMode 218 OxDA ToMT Request error mode ReqErrorModeAck 219 OxDB To host Device returns error mode SetErrorMode 218 OxDA To MT Host sets error mode Set
30. et the user can set the MT into the Measurement State In this state the MT starts outputting the data based the current configuration settings The MT states are discussed in the Section 3 The messages used in Config and Measurement state are described in Section 4 In this section the generic format of a message is first explained next is described how to use the message in general and finally all the messages are described grouped by functionality Section 5 lists some examples of how to use the MT binary data communication protocol Additional information about the MT such as a list of factory default values and table of maximum sample frequencies can be found in section 6 The last section gives a message reference overview of the MT messages with a short description see section 7 Document MT0O101P K Xsens Technologies B V 2 MT Low Level Communication Protocol Documentation XSens 3 States The MT has two states i e Config and Measurement state In the Config State various settings can be read and written and in the Measurement state the MT will output its data message which contains data dependent on the current configuration There are two different ways to enter the Config State or the Measurement State At power up the MT starts the WakeUp procedure and it will send the WakeUp message If no action is taken the device enters the Measurement State But if the WakeUpAck message is sent within 500ms after reception
31. ettingsAck 217 OxD9 To host Device returns SyncOut setting SetSyncOutSettings 216 OxD8 To MTi Host sets a SyncOut setting SetSyncOutSettingsAck 217 OxD9 To host Device acknowledges SetSyncOutSettings message Configuration messages Section 4 3 5 Message MID Direction Description ReqConfiguration 12 OxOC To MT Request the configuration of device For logging quick setup purposes Configuration 13 OxOD To host Contains the configuration of device ReqPeriod 4 0x04 ToMT Request current sampling period ReqPeriodAck 5 0x05 To host Device returns sampling period SetPeriod 4 0x04 ToMT Host sets sampling period 10 500Hz SetPeriodAck 5 0x05 To host Device acknowledges SetPeriod message ReqOutputSkipFactor 212 OxD4 To MT Request how many times the data output is skipped before sending a MTData message ReqOutputSkipFactorAck 213 OxD5 To host Device returns OutputSkipFactor Document MT0O101P K Xsens Technologies B V 41 MT Low Level Communication Protocol Documentation SetOutputSkipFactor SetOutputSkipFactorAck ReqObjectAlignment ReqObjectAlignmentAck SetObjectAlignment SetObjectAlignmentAck ReqOutputMode ReqOutputModeAck SetOutputMode SetOutputModeAck ReqOutputSettings ReqOutputSettingsAck SetOutputSettings SetOutputSettingsAck 212 OxD4 213 0xD5 224 OxE0 225 OxE1 224 OxE0 225 OxE1 208 OxDO 209 OxD1 208 OxDO 209 OxD1 210 OxD2 211 OxD3 210 OxD2 211 OxD3 Data related messages
32. eturns output settings Host sets output settings Device acknowledges message SetOutputSkipfactor SetOutputSettings Description Host requests device to send MTData message Message with un calibrated raw data calibrated data orientation data or GPS PVT data Description Request heading settings Device returns heading Host sets output mode Device acknowledges SetHeading message Resets the orientation Device acknowledges ResetOrientation message Request UTC Time Device return UTC Time Request available scenarios Device return available scenarios Request current used scenario Device return current scenario Host set current scenario Device acknowledges SetCurrentScenario Request current used gravity magnitude Device returns current gravity magnitude Host set gravity magnitude Device acknowledges SetGravityMagnitude Request current used lever arm GPS Device returns current lever arm GPS Host set current lever arm GPS Document MT0101P K Xsens Technologies B V 42 MT Low Level Communication Protocol Documentation XSens SetleverArmGPSAck 105 0x69 To host Device acknowledges SetLeverArmGPS ReqMagneticDeclination 106 Ox6A To MT Request current used magnetic declination ReqMagneticDeclinationAck 107 Ox6B To host Device returns current magnetic declination SetMagneticDeclination 106 Ox6A To MT Host set current magnetic declination SetMagneticDeclinationAck 107 Ox6B To host Device acknowledg
33. for description of the data field of the received acknowledge PARAM PARAM defines which of the SyncOut settings should be returned by the acknowledge message See following table PARAM value Setting O 0x00 SyncOut mode 1 0x01 Skip factor 2 0x02 Offset 3 0x03 Pulse width SetSyncOutSettings MID 216 OxD8 DATA PARAM VALUE 1 N bytes Direction To MTi Valid in Config State Set a SyncOut setting defined by the PARAM field with the value specified with the VALUE field Use SyncOut to synchronize other external hardware with the MIT Only the standard version of the MTi has an output pin that can be connected to other hardware which can be synchronized with the MTi See MTi and MTx User Manual MTi_MTx or MTi G User Manual MTi G for more information about the SyncOut pin PARAM The PARAM value 1 byte indicates which SyncOut setting will be set The VALUE field which can be either two or four bytes long defines the new value of the setting See table for the different PARAM values PARAM value O 0x00 1 0x01 2 0x02 3 0x03 Setting SyncOut mode Skip factor Offset Pulse width gt Please note that the MTx does not support the SyncOut settings Document MT0101P K Xsens Technologies B V 17 MT Low Level Communication Protocol Documentation XSens VALUE SyncOut mode Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 See the next table for the description of the SyncOut mode bits
34. host MID 97 0x61 DATA UTCTime 12 bytes Contains UTC Time DATA B Description Nanoseconds of second range 0 1 000 000 000 Year range 1999 2099 Month range 1 12 Day of Month range 1 31 Hour of Day range 0 23 Minute of Hour range 0 59 seconds of Minute range 0 59 0x01 Valid Time of Week 0x02 Valid Week Number 0x04 Valid UTC Leap Seconds already known a ONO FO xo NOTE Only supported by MTi G Document MT0O101P K Xsens Technologies B V 35 MT Low Level Communication Protocol Documentation 5 MT low level communication protocol example This section shows the communication between the host and MT as data bytes NOTE The MT Manager has a tool emulating a console to view and input raw MT message and view the hexadecimal message flow simultaneously This is a very convenient tool to get to know the MT communication protocol in detail and to access all advanced functionality directly Please refer to the MT Manager User Manual MTM for more details The byte values of the following examples are shown in hexadecimal Please check if your application has also a hexadecimal view and the capability to send user input entered as hexadecimal strings xl z Ra send Message Description SES asurement v Message Data FA FF 1000 Send To 100300776 COM 59 988 gt COM 59 23 FA FF 32 12 3F 23 03 4A 3D AE 66 61 BC ED D9 4B 3F 44 OA AB 07 2C 27 lt 20080
35. id in Measurement State This message can be used to ask the MT to send data to the host Normally the MT will send the MTData message automatically according to the sampling period and output skip factor settings If however the OutputSkipFactor is set to 65535 OxFFFF the MT will not send the MTData except if the user sends ReqData MTData MID 50 0x32 DATA DATA length variable Direction To host Valid in Measurement State This message contains the output data depending on the current OutputMode and OutputSettings The data field can contain multiple data outputs but the order of outputs is always the same The following order is used disabled outputs must be omitted GPS PVT data Temp Calibrated data output Orientation data output Auxiliary data output Position Velocity Status Sample counter Sete ee Ye RAW inertial data output can not be used together with any of the other outputs except GPS PVT data The RAW inertial data and GPS PVT data should be used together The following text explains the data values of each output DATA The data can contain multiple outputs All the different outputs are described separately here If not specified otherwise each data value is 4 bytes long and corresponds with the single precision floating point value as defined in the IEEE 754 standard float Un calibrated RAW inertial data output mode 20 bytes Contains the un calibrated raw data output of the accelerations rate
36. ime Bit 3 2 Orientation Mode OO Quaternion 01 Euler angles 10 Matrix Bit 6 4 Calibration Mode Bit 4 O Enable acceleration XYZ output 1 Disable acceleration XYZ output Bit5 O Enable rate of turn XYZ output 1 Disable rate of turn XYZ output Bit6 O Enable magnetometer XYZ output 1 Disable magnetometer XYZ output Bit 7 Reserved Bit 9 8 Output Format 00 Float output default 01 Fixed Point Signed 12 20 format 10 Fixed Point Signed 16 32 format High precision mode 6 bytes Bit 11 10 Auxiliary Mode Bit 10 O Enable analog in 1 output 1 Disable analog in 1 output Bit 11 O Enable analog in 2 output 1 Disable analog in 2 output Bit 13 12 Reserved Bit 16 14 000 LLA WGS84 Bit 18 17 00 m s XYZ Bit 30 19 Reserved Document MT0O101P K Xsens Technologies B V 24 MT Low Level Communication Protocol Documentation XSens Bit 31 O Use default co ordinate system X North Z up 1 Use X North Z down North East Down NED convention for both LTP and MT body fixed coordinate system Output Format Float DEFAULT The default format used by the MT is FLOAT FLOAT is 4 bytes long and corresponds with the single precision floating point value as defined in the IEEE 754 standard float Output Format Fixed point signed 12 20 format This is a two s complement fixed point format It consists of 12 integer bits and 20 fractional bits There are several ways to convert a 12 20 for
37. in data field Set Heading is available for the MTi and MTx only HEADING HEADING is a single precision floating point number 4 bytes The valid range is specified as n 7 Default value is zero ReqMagneticDeclination MID 106 Ox6A DATA n a Direction To MT Valid in Config State Request the current magnetic declination setting see SetMagneticDeclination for information about data field of received acknowledge Magnetic declination is valid for MTi G only SetMagneticDeclination MID 106 Ox6A DATA MAGNETICDECLINATION 4 bytes Direction To MT Valid in Config State Sets the magnetic declination with the value specified in data field MAGNETICDECLINATION MAGNETICDECLINATION is a single precision floating point number 4 bytes The valid range is specified as n 7 Default value is zero Magnetic declination is valid for MTi G only Document MT0101P K Xsens Technologies B V 30 MT Low Level Communication Protocol Documentation XSens RegAvailableScenarios MID 98 0x62 Direction To MT Valid in Config State NOTE For MTi and MTx this is not supported in firmware version 2 0 and lower Requests the available Xsens Kalman Filter XKF Scenarios from the MTi G MTi or MTx AvailableScenarios Contains information about available filter scenarios that are stored on the non volatile memory of the MTi G MTi or MTx Data contains the following for remaining scenarios are of type DATA
38. le sending connect the MT to the USB converter 5 Stop sending when the WakeUp message is received All settings shown in the previous table are now reset This procedure during MT device WakeUp ensures that communication can always be restored with the device even if erroneous settings have been programmed by accident Document MT0101P K Xsens Technologies B V 39 MT Low Level Communication Protocol Documentation 7 Message Reference Listing This section gives a quick reference of all the valid messages messages see Section 4 WakeUp and State messages Section 4 3 1 Message MID Direction WakeUp 62 Ox3E To host WakeUpAck 63 Ox3F To MT GoToConfig 48 0x30 To MT GoToConfigAck 49 0x31 To host GoToMeasurement 16 0x10 To MT GoToMeasurementAck 17 0x11 To host Reset 64 0x40 To MT ResetAck 65 0x41 To host Informational messages Section 4 3 2 Message MID Direction ReqDID O 0x00 To MT DevicelD 1 0x01 To host InitMT 2 0x02 To MT InitMTResults 3 0x03 To host ReqProductCode 28 Ox1c ToMT ProductCode 29 Ox1d To host ReqFWRev 18 0x12 To MT FirmwareRev 19 0x13 To host ReqDataLength 10 OxOA To MT DataLength 11 OxOB To host Error 66 0x42 To host ReqGPSStatus 166 OxA6 To MT GPSStatus 167 OxA7 To host Device specific messages Section 4 3 3 Message MID ReqBaudrate Direction 24 0x18 To MT XSens For more information about the use of the Description The device sends this m
39. mat number to a double precision floating point number The best way is to place the values into a 32 bit integer The floating point value can then be computed by casting the value to double precision and dividing by 220 Output Format Fixed point signed 16 32 format high precision This format consists of a signed 16 bit integer and an unsigned 32 bit integer The short value is the integral part of the number while the long value represents the fractional part Concatenating the two values will effectively yield a 6 byte fixed point number with the radix point after the 16 bit but note that the 32 fractional bits are sent before the 16 integer bits There are several ways to convert a 16 32 format number to a double precision floating point number The best way is to place the values into a 64 bit integer where the short value should be sign extended the highest bit should be copied into the upper 16 bits of the 64 bit integer which can often be accomplished by casting to a long value The floating point value can then be computed by casting the value to double precision and dividing by 2432 The high precision format is recommended to avoid quantization in position output LLA for the MTi G when high precision is required for position Document MT0O101P K Xsens Technologies B V 25 MT Low Level Communication Protocol Documentation XSens 4 3 6 Data related messages ReqData MID 52 0x34 DATA n a Direction To MT Val
40. n of the data bytes is message specific i e depending on the MID value the meaning of the data bytes is different The data is always transmitted in big endian format See the description of the specific message for more details about the data bytes Checksum This field is used for communication error detection If all message bytes excluding the preamble are summed and the lower byte value of the result equals zero the message is valid and it may be processed The checksum value of the message should be included in the summation 4 2 Message usage Generally a message with a certain MID value will be replied with a message with a MID value that is increased by one i e the acknowledge message Depending on the message type the acknowledge message can have a data field no fixed length or not If nothing is specified the data field does not exist In some cases an error message will be returned MID 66 0x42 This occurs in case the previous message has invalid parameters is not valid or could not be successfully executed An error message contains an error code in its data field Example Requesting the device ID of an MT Sending message ReqDID OxFA OxFF 0x00 0x00 0x01 hexadecimal values Receiving message Acknowledge DeviceID OxFA OxFF 0x01 0x04 HH HL LH LL CS hexadecimal values The requested Device ID is given in the acknowledge message DevicelID here shown as HH HL LH LL the checksum is CS As you can see the
41. ned integer value and NOT a float value Position data output mode LLA 12 bytes Contains the latitude longitude and altitude in floats that represent the position of the MTi G Velocity data output mode VeIXYZ 12 bytes Contains the velocity X Y and Z in that represent the velocity of the MTi G Note that velocity in North East Down can be obtained by changing bit 31 in the SetOutputSettings DATA field Document MT0101P K Xsens Technologies B V 28 MT Low Level Communication Protocol Documentation XSens Status 1 byte This byte contains flags that represent the status and estimated validity of the output of the MT The currently defined flags are summarized below A flag is set to 1 when the relevant condition is true Self Test This flag indicates if the power up self test completed successfully XKF Valid This flag indicates if input into the XKF orientation filter is reliable and or complete If for example the measurement range of internal sensors is exceeded orientation output cannot be reliably estimated and the XKF flag will drop to 0 For the MTi G the XKF flag will also become invalid if the GPS status remains invalid for an extended period GPS Fix This flag indicates if the GPS unit has a proper fix The flag is only available in MTi G units NoRotation Status only available for MTi MTx This flag indicates the status of the no rotation update procedure in the filter after the Se
42. ng frequency before the next MTData message is sent l e at sample period of 5 0ms 200Hz and a skip factor of 4 the measurement is running at 200Hz but the data is sent at a rate of 40Hz not 50Hz See also SetPeriod for more information about the relationship between the sampling period and output skip factor If SKIPFACTOR is set to 65535 OxFFFF no data will be sent to the host and ReqData can be use to request an MTData message at an arbitrary time This works also if Syncin mode is enabled NOTE The baudrate may limit the sample frequency that can be used for a specific output mode and output setting due to the amount of data that must be transmitted throughput please refer to the device specific manuals MTi_MTx and MTi G for further details SKIPFACTOR Description 65535 OxFFFF Skipfactor value 65535 OxFFFF Do not send MTData automatically ReqObjectAlignment MID 224 OxE0O DATA n a Direction To MT Valid in Config State Request the internally stored object alignment matrix which is set by the ResetOrientation message or SetObjectAlignment message For information about data field of received acknowledge see SetObjectAlignment Document MT0O101P K Xsens Technologies B V 21 MT Low Level Communication Protocol Documentation XSens SetObjectAlignment MID 224 OxEO DATA MATRIX 9x4 bytes Direction To MT Valid in Config State Set the object alignment matrix MATRIX Is equal to the object alig
43. nment matrix which is a 3x3 matrix of which all elements are specified in floats in the order first row then column See the section about arbitrary alignment in the MTi and MTx User Manual MTi_MTx or MTi G User Manual MTi G for more information and an example for setting the object alignment to a known orientation Correspondence between the data fields and the alignment matrix is shown below abe Roy d e f gh i ReqOutputMode MID 208 OxDO DATA n a Direction To MT Valid in Config State Request the current output mode See SetOutputMode for information about data field of the received acknowledge SetOutputMode MID 208 OxDO DATA MODE 2 bytes Direction To MT Valid in Config State Sets the output mode of the MT The settings here combined with the SetOutputSettings define the content of the DATA field in the MTData message The output mode can be set to various output modes of which most of them can be combined like for example calibrated sensor data and orientation data The un calibrated RAW inertial data output however can not be used together with any of the other outputs except GPS PVT data The RAW inertial data and the GPS PVT data messages should often be used together NOTE The baudrate may limit the sample frequency that can be used for a specific output mode and output setting due to the amount of data that must be transmitted throughput please refer to the device specific manuals MTi_MTx and M
44. nologies B V iii MT Low Level Communication Protocol Documentation 1 Quaternion DOF DSP GPS IMU LLA MT MTB MTM PVT SDK UTC WR A Xbus XKF 3 XKF 6 XML LLCP MEM MTi_MTx MTi G XBM MTM SDK Terms abbreviations and references A non commutative extension of complex numbers Degrees Of Freedom Digital Signal Processor Global Positioning System Inertial Measurement Unit Latitude Longitude Altitude Motion Tracker MT Binary Communication Protocol MT Manager Position Velocity Time Software Development Kit Coordinated Universal Time Wireless Receiver Xsens digital data bus system Xsens Kalman Filter 3 DOF Xsens Kalman Filter 6 DOF eXtended Markup Language XSens MT Low Level Communication Protocol Documentation pdf document id MT0101P Magnetic Field Mapper Documentation pdf document id MT0202P MTi and MTx User Manual and Technical Documentation pdf document id MTO100P MTi G User Manual and Technical Documentation pdf document id MT0137P XM B User Manual pdf document id XM0100P XM B Technical Documentation pdf document id XM0101P MT Manager User Manual pdf document id MT0216P MT Software Development Kit Documentation pdf document id MTO200P Document MT0101P K Xsens Technologies B V 1 MT Low Level Communication Protocol Documentation XSens 2 Introduction This document describes how to communicate with
45. of turn and magnetic field in X Y and Z axes These values are equal to the analog digital converter readings of the internal sensors The data values are NOT float values but 16 bit unsigned integer values Document MT0O101P K Xsens Technologies B V 26 MT Low Level Communication Protocol Documentation XSens GPS PVT data output mode 44 bytes When the MTi G output mode is set to GPS PVT data the following message structure will be output by the MTi G The data message contains pressure sensor and GPS data as described below The description of each data field is given in the following table ITOW Hacc Vacc Sacc bGPS ve 66 2 3 7 11 15 19 23 27 31 35 39 43 offset Description of MTi G GPS PVT Sensor Data Message Structure Byte Number Purpose Comment offset format Press O Lu f2 Pa Pressure value in Pascals bPrs 2 U1 Pressure sensor status When the value decreases elek ee cc a E E E 7 Ju te7 deg latitude S ria mm Attude Height above Elipeold Mean Sea Level cm s NEDnorthvelocity OSS Horizontal Accuracy Estimate Expected error wt standard deviation a Se ALT VEL_N VEL_E VEL_D Hacc Vacc Vertical Accuracy Estimate Expected error standard deviation cm s Speed Accuracy Estimate Expected error standard deviation GPS status byte or GPS data age When the value decreases new GPS data is available The value is reset to zero upon receipt of
46. on Protocol Documentation XSens A 16 bit value having an arbitrary value set by the user Default value is zero RestoreFactoryDef MID 14 Ox0E DATA n a Direction To MT Valid in Config State If this message is sent to the MT the factory defaults are restored All settings that have changed will be discarded including object alignments filter settings etc For more information about the default settings values see section 6 1 ReqTransmitDelay MID 220 OxDC DATA n a Direction To MT Valid in Config State Requests the delay value which equals the minimum time between last byte reception and transmission start of acknowledge in RS485 mode SetTransmitDelay MID 220 OxDC DATA SETTING 2 bytes Direction To MT Valid in Config State An unsigned 16 bit value that defines the number of clock ticks to delay the transmission start after last byte reception One clock tick is equal to 1 29 4912 MHz 33 9ns This setting has no effect on RS 232 type MTs SETTING Description Bit 16 0 Delay value Valid value is 590 20 usec to 65535 2 2 msec StorexkfState MID 138 Ox8A DATA N A Direction To MT Valid in Config State Stores the estimated biases of the physical sensors in the eMTS data of the MT Document MT0O101P K Xsens Technologies B V 14 MT Low Level Communication Protocol Documentation XSens 4 3 4 Synchronization messages ReqSyncIinSettings MID 214 OxD6 DATA PARAM 1 byte Direction To MT
47. range Parameter sent is invalid or not within range MTi G requests status information from the GPS receiver at regular intervals On request this data is sent from cache Also refer to the GPSStatus message below GPSStatus MID DATA Direction Valid in 167 0xA7 GPSSTATUS To MTi G Config State NOTE Only supported by MTi G Acknowledge of the ReqGPSStatus message The DATA field contains the GPS Satellite Status information of the GPS receiver The MTi G requests this information from the GPS receiver at regular intervals On request the latest data is sent from cache GPSSTATUS DATA B 0 1 NCH 5 2 NCH 5 3 NCH 5 4 NCH 5 5 NCH 5 Description Number of channels in range Repeat the following block for all channels Channel number range 0 NCH 1 NCH number of channels Satellite ID Bitmask made up of the following values 0x01 SV is used for navigation 0x02 Differential correction data is available for this SV 0x04 Orbit information is available for this SV ephemeris or Almanach 0x08 Orbit information is Ephemeris 0x10 SV is unhealthy shall not be used Signal Quality indicator range 0 7 0 This channel is idle 1 2 Channel is searching 3 Signal detected but unusable 4 Code lock on Signal 5 6 Code and Carrier locked 7 Code and Carrier locked receiving 50bps data Carrier to Nose Ratio Signal Strength Document MT0101P K Xsens Technologies B V 11 MT
48. reset to perform during Measurement State To store the present settings enter the Config State and send the same message again with RESET equal to zero CODE Description O Ox0000 Store current settings only in config mode 1 Ox0001 Heading reset NOT supported by MTi G 2 0x0002 RESERVED 3 Ox0003 Object reset 4 0x0004 Align reset NOT supported by MTi G SetNoRotation MID 34 0x22 DATA Duration seconds 2 bytes Direction To MT Valid in Measurement State Initiates the no rotation update procedure For more information about the no rotation update procedure see MTi and MTx User Manual MTi_MTx Note that the acknowledge does not reflect the result of the SetNoRotation message The result of the SetNoRotation message are represented in bits 3 and 4 of the status byte see MTdata 0x32 With the SetProcessingFlags message an initial gyroscope bias estimation upon start up of the MTi MTx can be activated Refer to the description of the SetProcessingFlags message for details DATA PARAM DATA Description 0 Duration seconds Duration of the no rotation update NOTE Not supported by MT NOTE For MTi and MTx this is not supported in firmware version 2 2 and lower Document MT0O101P K Xsens Technologies B V 34 MT Low Level Communication Protocol Documentation RequTCTime Direction To MT MID 96 0x60 Request UTC Time from sensor NOTE Only supported by MTi G UTC Time Direction To
49. tNoRotation message has been sent 11 Running with no rotation assumption 10 Error Rotation detected procedure not started sticky 01 Estimation complete some samples rejected sticky 00 Estimation complete no errors Sample counter 2 bytes The optional sample counter is a 16 bit unsigned integer value that is increased for each transmission of the MTData message If its maximum value is reached i e 65535 OxFFFF it will wrap and start at zero again See also SetErrorMode for the relation between the sample counter and the error mode UTC Time 12 bytes Besides the sample counter it is also possible to let the data be time stamped by UTC time This data package is identical to the result of ReqgUTCTime The CMT C class has an easy to use member function to retrieve the individual MTData DATA fields gt Refer to MT Software Development Kit Documentation SDK documentation for further details Document MT0O101P K Xsens Technologies B V 29 MT Low Level Communication Protocol Documentation XSens XKF Filter messages ReqHeading MID 130 0x82 DATA n a Direction To MT Valid in Config State Request the current heading setting see SetHeading for information about data field of received acknowledge SetHeading is available for the MTi and MTx only SetHeading MID 130 0x82 DATA HEADING 4 bytes Direction To MT Valid in Config State Sets the heading with the value specified
50. ter device settings shown in the next table are also reset Property Default value Message section nr Location 0 SetLocationTD 4 3 3 Object alignment Unity matrix ResetOrientation 4 3 7 Headin o setHeading 43 7 XKF Scenario SetCurrentScenario 4 3 7 Document MT0101P K Xsens Technologies B V 38 MT Low Level Communication Protocol Documentation XSens 6 2 Restore communication If the MT has been programmed with a baudrate setting that is not compatible with software or is unknown to the user a restore communication procedure can be applied This procedure will set a number of settings to its default values including the baudrate The following settings will be reset Property Default value Output mode Orientation output Output settings Orientation in quaternion mode Sample counter Sample frequency 100 Hz Baudrate 115k2 bps Output skip factor OT You can either use the MT Manager see Tools menu or perform the procedure manually To restore the settings manually follow the following procedure 1 Disconnect the MT from the USB serial converter cable 2 Insert the USB serial converter cable into a free USB port and open the respective virtual COM port with the following settings baudrate 115k2 8 databits no parity and 2 stopbits 3 Start sending the byte value 222 OxDE repeatedly but make sure there is a gap of 0 1 to 0 5 ms between the words no back to back transfer 4 Whi
51. ting 4 3 1 WakeUp State messages WakeUp MID 62 Ox3E DATA n a Direction To host Valid in WakeUp procedure At power up or after issuing a reset this message is sent to the host If the host sends WakeUpAck MID 63 Ox3F within 500ms after reception of this message the MT enters the Config State else Measurement State GoToConfig MID 48 0x30 DATA n a Direction To MT Valid in Measurement State and Config State Switch the active state of the device from Measurement State to Config State This message can also be used in Config State to confirm that Config State is currently the active state GoToMeasurement MID 16 0x10 DATA n a Direction To MT Valid in Config State Switch the active state of the device from Config State to Measurement State The current configuration settings are used to start the measurement Reset MID 64 0x40 DATA n a Direction To MT Valid in Config State and Measurement State Sending this message will cause the MT to reset and to activate the WakeUp procedure An acknowledge message will be sent to confirm reception of the Reset message 4 3 2 Informational messages ReqDID MID O 0x00 DATA n a Direction To MT Valid in Config State Document MT0101P K Xsens Technologies B V g MT Low Level Communication Protocol Documentation XSens Request to send the device identifier or serial number MT acknowledges by sending the DeviceID message DevicelID MID 1 0x01 DATA IDH
52. vice Can be used for logging purposes include the Configuration message in the log file to store the settings for offline processing of the data Configuration MID 13 Ox0D DATA CONFIGURATION 118 bytes Direction To host Valid in Config State Acknowledge of ReqConfiguration message Data field contains the current configuration of the MT CONFIGURATION The CONFIGURATION data contains the following information For more information about the different fields check the corresponding message description offset length field description B B 0 4 Master device ID 4 2 Sampling period 6 2 Output skip factor 8 2 Syncin settings Mode 10 2 Syncin settings Skip Factor 12 4 Syncin settings Offset 16 8 Date format YYYYMMDD can be set by host 24 8 Time format HHMMSSHH can be set by host 32 32 Reserved host 64 32 Reserved client 96 2 Number of devices 1 0x0001 98 4 Device ID Same as master device ID 102 2 Data length of MTData message 104 2 Output mode 106 4 Output settings 110 8 Reserved Document MT0O101P K Xsens Technologies B V 19 MT Low Level Communication Protocol Documentation XSens ReqPeriod MID 4 0x04 DATA n a Direction To MT Valid in Config State Request the current sample period The MT replies with ReqPeriodAck The data field of this message contains the sample period For the description of the data field see SetPeriod SetPeriod MID 4 0x04 DATA PERIOD 2 bytes
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