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DataAndConfigurationMessages / 74ExternalAuxiliaryChannels

External auxiliary channel

Channel Number74
Total Length5 bytes
ChannelData1Data2Data3Checksum

Sensor location = Data1

  1. External Auxiliary channel 1 - (Throttle Position)
  2. External Auxiliary channel 2 - (Lambda 1 Short Term Trim)
  3. External Auxiliary channel 3 - (Lambda 2 Short Term Trim)
  4. External Auxiliary channel 4 - (Lambda 1 Long Term Trim)
  5. External Auxiliary channel 5 - (Lambda 2 Long Term Trim)
  6. External Auxiliary channel 6 - (Fuel Inj 1 Pulse Width)
  7. External Auxiliary channel 7 - (Fuel Inj 2 Pulse Width)
  8. External Auxiliary channel 8 - (Fuel Inj 3 Pulse Width)
  9. External Auxiliary channel 9 - (Fuel Inj 4 Pulse Width)
  10. External Auxiliary channel 10 - (Fuel Inj 5 Pulse Width)
  11. External Auxiliary channel 11 - (Fuel Inj 6 Pulse Width)
  12. External Auxiliary channel 12 - (Fuel Inj 7 Pulse Width)
  13. External Auxiliary channel 13 - (Fuel Inj 8 Pulse Width)
  14. External Auxiliary channel 14 - (Fuel Inj 1 Cut Level)
  15. External Auxiliary channel 15 - (Fuel Inj 2 Cut Level)
  16. External Auxiliary channel 16 - (Fuel Inj 3 Cut Level)
  17. External Auxiliary channel 17 - (Fuel Inj 4 Cut Level)
  18. External Auxiliary channel 18 - (Fuel Inj 5 Cut Level)
  19. External Auxiliary channel 19 - (Fuel Inj 6 Cut Level)
  20. External Auxiliary channel 20 - (Fuel Inj 7 Cut Level)
  21. External Auxiliary channel 21 - (Fuel Inj 8 Cut Level)
  22. External Auxiliary channel 22 - (Ignition Cut Level)
  23. External Auxiliary channel 23 - (ISBV 1 Open)
  24. External Auxiliary channel 24 - (ISBV 2 Open)
  25. External Auxiliary channel 25 - (Nitrous)
  26. External Auxiliary channel 26 - (Auxiliary 1)
  27. External Auxiliary channel 27 - (Auxiliary 2)
  28. External Auxiliary channel 28 - (Auxiliary 3)
  29. External Auxiliary channel 29 - (Auxiliary 4)
  30. External Auxiliary channel 30 - (Fuel Aux Temp Comp)
  31. External Auxiliary channel 31 - (Fuel Aux Volt Comp)

Data has a resolution of 0.1 and a range of -3276.8 to 3276.7

If Data3 & 0x80 = 1, Output = - (65536- (Data2 + Data3 x 2^8))/10
Else Output = (Data2 + Data3 x 2^8)/10

The following external auxiliary data channels are output by the SPEEDBOX, SPEEDBOX-INS, GPS2, RTK BASE STATION, RTLive and/or VIDEO4HD.

  • External auxiliary channel 6:
    • Time since last differential correction (GPS2 and SPEEDBOX only)
      Outputs time in seconds since last incoming differential correction.
      A value of 60 or greater implies that corrections have effectively ceased.
  • External auxiliary channel 7: RTLive connection status (RTLive only)
GSM module not initialized 0
GSM module initialize OK 1
GSM module SIM OK 2
RT Live connected to network 3
RT Live connected to internet 4
RT Live connected to server 5
  • External auxiliary channel 8: RT Live data upload rate in Kbit/sec (RTLive only)
  • External auxiliary channel 9: Percentage of remaining memory available for save RUN message data, before upload. (RTLive only)
  • External auxiliary channel 10: Movement detection count (RTLive only)
  • External auxiliary channel 11:
    • Base station status (RTK BASE STATION only)
      Outputs base station status, as defined below.
      Base station status codes:
      0: Waiting for GPS
      1: Averaging position (standalone)
      2: Surveying location (corrected)
      10: Position fixed
    • Time since last movement in seconds (RTLive only)


  • External auxiliary channel 12:
    • Estimated time to fix position (RTK BASE STATION only)
      Estimated time to fix position and commence output of corrections [s]
    • Run data uploading status (RTLive only)
      1 = Uplaoding
      0 = Not uploading


  • External auxiliary channel 13:
    • Percentage of free net buffers (VIDEO4HD only)
      Outputs the percentage of free network buffers
    • Next fragment number to write to memory in memory chip 1 (RTLive only)
      Note: - value should multiply by 10 to get final figure


  • External auxiliary channel 14:
    • Percentage of free disk buffers (VIDEO4HD only)
      Outputs the percentage of free disk buffers
    • Next fragment number to write to memory in memory chip 2 (RTLive only)
      Note: - value should multiply by 10 to get final figure


  • External auxiliary channel 15:
    • Camera Index (VIDEO4HD only)
      Camera index of the message (0 to 7)
    • Last fragment upload in memory chip 1 (RTLive only)
      Note: - value should multiply by 10 to get final figure


  • External auxiliary channel 16:
    • File index (VIDEO4HD only)
      Currently recording file index of the camera (1 to 31)
    • Last fragment upload in memory chip 2 (RTLive only)
      Note: - value should multiply by 10 to get final figure


  • External auxiliary channel 17:
    • GNSS observables status (GPS2 only)
      Each 4 bits of this message indicate the number of good observables (in the range 0..15) being generated by the unit's internal GNSS receiver for each of 4 GNSS constellation/frequency combinations as indicated below:
      bits 0..3: Number of GPS L1 good observables
      bits 4..7: Number of GPS L2 good observables
      bits 8..11: Number of GLONASS L1 good observables
      bits 12..15: Number of GLONASS L2 good observables
    • Run data transmission information (RTLive only)
      Bit 0 – Fragment Transmitted to GSM module in first Try
      Bit 1 - Fragment Transmitted to GSM module in second Try
      Bit 2 – Waiting to transmit as the second try
      Bit 3 - Fragment Transmitted to GSM module in third Try
      Bit 4 – Waiting to transmit as the third try
      Bit 5 - Fragment Transmitted to GSM module in fourth Try
      Bit 6 – Waiting to transmit as the fourth try
      Bit 7 - Fragment Transmitted to GSM module in fifth Try
      Bit 8 – Waiting to transmit as the fifth try
      Bit 9 – Fragment Transmitted to GSM module in sixth Try


  • External auxiliary channel 18:
    • Incoming corrections observables status (GPS2 only)
    Each 4 bits of this message indicate the number of good observables (in the range 0..15) received as incoming correction data for each of 4 GNSS constellation/frequency combinations as indicated below:
    bits 0..3: Number of GPS L1 good observables
    bits 4..7: Number of GPS L2 good observables
    bits 8..11: Number of GLONASS L1 good observables
    bits 12..15: Number of GLONASS L2 good observables
    • Run data upload exit conditions (RTLive only)
      Bit 0 - No fragments to Transmit
      Bit 1 - feedback fragment already received
      Bit 2 - Not correct journey index to upload
      Bit 3 – Not correct fragment to upload at this moment
      Bit 4 – exit from search while loop due to “ fragment to check >= next fragment to write”
      Bit 5 – exit from search while loop due to “fragment to check > FINAL_FALSH_FRAGMENT”
      Bit 6 – exit from search while loop due to “already upload a fragment in last iteration”


  • External auxiliary channel 19: RTCM incoming corrections status (SPEEDBOX and GPS2 only)
    The format of this message is dependent on whether it has been transmitted by a SPEEDBOX or by a GPS2.
    For the SPEEDBOX, the raw unscaled 16 bit value contains the message type of the last rtcm v3 message received. A value of zero indicates a checksum error. One auxiliary message 74.19 is output for every rtcm correction message received.
    For the GPS2, auxiliary message 74.19 is output at intermittent intervals, and the raw u16 value is interpreted as a bit-field where each set bit indicates that that correction type has been received at least once since the last output of this message. The messages indicated by each bit are:
    bit 0: rtcm v3 message 1001
    bit 1: rtcm v3 message 1002
    bit 2: rtcm v3 message 1003
    bit 3: rtcm v3 message 1004
    bit 4: rtcm v3 message 1005
    bit 5: rtcm v3 message 1006
    bit 6: rtcm v3 message 1007
    bit 7: rtcm v3 message 1008
    bit 8: rtcm v3 message 1009
    bit 9: rtcm v3 message 1010
    bit 10: rtcm v3 message 1011
    bit 11: rtcm v3 message 1012
    bit 12: Any other rtcm v3 message not listed above
    bit 13: Any rtcm v2 message
    bit 14: Reserved
    bit 15: rtcm CRC error detected


  • External auxiliary channel 20: INS overall accuracy (SPEEDBOX-INS only)
    INS overall accuracy [%]


  • External auxiliary channel 21: Output offset forward
    Forward output offset in cm. +ve for forward, -ve for backward.


  • External auxiliary channel 22: Output offset right
    Right output offset in cm. +ve for right, -ve for left.


  • External auxiliary channel 23: Output offset down
    Down (below) output offset in cm. +ve for down, -ve for up.


  • External auxiliary channel 24: Combined speed accuracy (SPEEDBOX-INS only)
    spd_acc [ms/s] * 100


  • External auxiliary channel 25: Yaw accuracy (SPEEDBOX-INS only)
    yaw_acc [degrees] * 100


  • External auxiliary channel 26: GPS status
GPS Status codes:
0: GPS module not detected
1: Searching for satellites
2: Insufficient satellites
3: Solution aborted
4: Solution failed
5: Exceeded maximum speed or altitude
6: Unused
7: Unused
8: Unused
9: Unused
10: Lock: Position but no speed
11: Lock: Doppler speed and position
12: Lock: Carrier speed and position
20: External solution: No lock
21: External solution: Standalone (autonomous) solution
22: External solution: Solution corrected with WAAS/SBAS
23: External solution: Code differential (DGPS) solution
24: External solution: Phase differential (RTK) solution with float ambiguities
25: External solution: Phase differential (RTK) solution with integer ambiguities


  • External auxiliary channel 27: INS convergence (SPEEDBOX-INS only)
    0->99%, INS not converged, convergence progress from 0.05 to 0.01 kf_convergence.
    100%, INS converged.


  • External auxiliary channel 28: Number of satellites (module 1)
    Number of satellites


  • External auxiliary channel 29: Number of satellites (module 2)
    Number of satellites


  • External auxiliary channel 30: Trigger input state
    trigger state (0 or 1)
    The state of the external trigger, note that this is only provided as a convenience for testing the operation of the trigger - do not use for timing.


  • External auxiliary channel 31: acb_convergence (SPEEDBOX-INS only)
    acb_convergence * 10000
    This is the current error weighting for brake distance, this is used by the RT run processor software
Page last modified on December 05, 2019, at 04:51 PM