REXGEN XML reference: analogue, digital, IMU and GNSS inputs

Configure the logger's own inputs: analogue and digital channels, the IMU, the GNSS receiver and internal values such as the clock.

Input blocks and the models that have them

Each input is a block that produces values. On its own it does nothing visible: record it with an SDMESSAGE, stream it with a USBMESSAGE or send it on CAN with a CANSIGNAL. Each block takes a UID attribute (required and unique in the file) and the optional Version, X and Y.

REXGEN 1 has none of these inputs. Channel numbers start at 0 on every model. Each entry in the settings lists gives the meaning, then whether the schema requires the element, its type and its default where one exists.

Analogue inputs (ADC_LIST)

ADC

This example from ADC2CAN_Only.xml reads analogue input 0 every 100 ms, unscaled.

<ADC UID="8">
  <PhysicalNumber>0</PhysicalNumber>
  <Rate>100</Rate>
  <ParA>1</ParA>
  <ParB>0</ParB>
</ADC>

PhysicalNumber

The analogue channel, counted from 0. Required. Unsigned byte.

Rate

Sampling period in milliseconds. 100 is 10 samples a second. The analogue inputs sample at up to 1 kHz. Required. Unsigned short.

ParA, ParB

Factor and offset applied to the reading: value = reading × ParA + ParB. Required. Float.

Digital inputs (DIGITAL_INPUT_LIST)

DIGITAL_INPUT

This example reads digital input 0 every 100 ms as a logic level that is active when high.

<DIGITAL_INPUT UID="11">
  <PhysicalNumber>0</PhysicalNumber>
  <SamplingRate>100</SamplingRate>
  <DigitalType>DIGITAL</DigitalType>
  <ActiveState>HI</ActiveState>
</DIGITAL_INPUT>

PhysicalNumber

The digital input channel, counted from 0. It is not a CAN bus number. Required. Unsigned byte.

SamplingRate

Sampling period in milliseconds. Required. Unsigned short. Default 10.

DigitalType

What is measured: DIGITAL (the level), FREQUENCY, IMPULSE (a pulse count) or PWM (the duty cycle). Required. Default DIGITAL.

ActiveState

The level that counts as active: HI or LOW. Required.

To wire the inputs, see REXDESK: log analogue and digital inputs.

Accelerometer and gyroscope (ACCELEROMETER_LIST, GYRO_LIST)

Add one block for each axis. The internal IMU is always PhysicalNumber 0. The IMU records at up to 1 kHz, so the shortest sampling period is 1 ms.

ACCELEROMETER

This example from IMU2CAN.xml reads the X axis every 100 ms on the ±16 g range.

<ACCELEROMETER UID="8">
  <PhysicalNumber>0</PhysicalNumber>
  <Axis>X</Axis>
  <SamplingRate>100</SamplingRate>
  <RangeHi>16</RangeHi>
  <RangeLow>-16</RangeLow>
</ACCELEROMETER>

PhysicalNumber

The accelerometer. Use 0 for the internal one. Required. Unsigned byte.

Axis

X, Y, Z or IMPACT. Required.

SamplingRate

Sampling period in milliseconds. Required. Unsigned short.

RangeHi, RangeLow

Upper and lower limits in g. They also set the range of the internal sensor. Use a range the sensor offers: ±2, ±4, ±8 or ±16 g on REXGEN 2 IMU GNSS. Required. Float.

GYRO

This example from IMU2CAN.xml reads the X axis every 100 ms on a ±500 range.

<GYRO UID="11">
  <PhysicalNumber>0</PhysicalNumber>
  <Axis>X</Axis>
  <SamplingRate>100</SamplingRate>
  <RangeHi>500</RangeHi>
  <RangeLow>-500</RangeLow>
</GYRO>

PhysicalNumber

The gyroscope. Use 0 for the internal one. Required. Unsigned byte.

Axis

X, Y or Z. Required.

SamplingRate

Sampling period in milliseconds. Required. Unsigned short.

RangeHi, RangeLow

Upper and lower limits of angular rate in °/s. They also set the range of the internal sensor. Required. Float.

GNSS (GNSSINTERFACE_LIST, GNSSMESSAGE_LIST)

A GNSSINTERFACE sets up the receiver. Each GNSSMESSAGE then picks one value from it, such as latitude or speed.

GNSSINTERFACE

This example from GNSS2CAN_Only.xml reads the internal receiver every 100 ms.

<GNSSINTERFACE UID="8">
  <PhysicalNumber>0</PhysicalNumber>
  <SamplingRate>100</SamplingRate>
  <MinimumSat>0</MinimumSat>
  <FilterCourseOverGround>false</FilterCourseOverGround>
  <FilterVelocity>false</FilterVelocity>
  <AutomaticMountAlignment>false</AutomaticMountAlignment>
  <MountYaw>0</MountYaw>
  <MountPitch>0</MountPitch>
  <MountRoll>0</MountRoll>
</GNSSINTERFACE>

PhysicalNumber

The receiver. The internal one is always 0. Optional. Unsigned byte. Default 0.

SamplingRate

Sampling period in milliseconds. It also changes the receiver's settings, and the fitted receiver sets the shortest period you can use. Required. Unsigned short.

MinimumSat

Minimum number of satellites. The examples set 0. Optional. Unsigned byte. Default 3.

Platform

The receiver's motion model: AUTOMOTIVE (default), STATIONARY, PEDESTRIAN, PORTABLE, MOTORBIKE, SEA, WRIST, ELECTRIC_KICK_SCOOTER, ROBOTIC_LAWN_MOWER or AIRBORNE_UP_TO_1g, _2g, _4g. Optional.

GNSS_System_LIST

Up to eight GNSS_System entries, each a Type (GPS, GLONASS, Galileo, BeiDou, QZSS, SBAS or IMES) with ChannelMin and ChannelMax. Optional.

FilterCourseOverGround, FilterVelocity

Enable the receiver's filtering of course and speed. Optional. Boolean. Default false.

IMU_Enable, AutomaticMountAlignment, MountYaw, MountPitch, MountRoll

Dead reckoning: IMU_Enable combines the IMU with GNSS. Give the logger's mounting angles in degrees, or let it align itself. Dead reckoning is a REXGEN Air feature. For the angles, see REXGEN Air: GNSS, dead reckoning and geofencing. Optional. Defaults false and 0.

Geofence_LIST

Up to four circular geofences, each a Latitude, Longitude and Radius. Geofencing is a REXGEN Air feature. Optional.

GNSSMESSAGE

This example from GNSS2CAN_Only.xml takes the latitude from receiver 8.

<GNSSMESSAGE UID="12">
  <InterfaceUID>8</InterfaceUID>
  <Type>LATITUDE</Type>
</GNSSMESSAGE>

InterfaceUID

UID of the GNSSINTERFACE. Required. Unsigned short.

Type

The value to take (see the list of Type values). Required.

InputUID

Optional. Unsigned short. Default 0.

The Type values the schema allows:

• Position and time: LATITUDE, LONGITUDE, ALTITUDE, GEOID_SEPARATION, DATETIME, GNSS_TIMESTAMP.
• Movement: SPEED_OVER_GROUND, COURSE_OVER_GROUND, GROUND_DISTANCE, ACCELERATION_X, _Y, _Z, ANGULAR_RATE_X, _Y, _Z.
• Vehicle attitude: VEHICLE_HEADING, VEHICLE_PITCH, VEHICLE_ROLL and their _ACCURACY values.
• Fix quality: QUALITY, NUMBER_SATELLITES, HORIZONTAL_ACCURACY, VERTICAL_ACCURACY, SPEED_ACCURACY.
• Geofences: GEOFENCE_1 to GEOFENCE_4.

The attitude, acceleration and angular rate values come from dead reckoning. To set up GNSS and the IMU in REXDESK, see REXDESK: set up GNSS and the IMU.

Internal parameters (INTERNAL_PARAMETER_LIST)

INTERNAL_PARAMETER

Internal parameters are values the logger knows about itself. This one, from RTC2CAN.xml, reads the real-time clock once a second as a 32-bit unsigned value.

<INTERNAL_PARAMETER UID="1200">
  <InputUID>0</InputUID>
  <Parameter_Type>RTC</Parameter_Type>
  <Value_Type>ULONG</Value_Type>
  <SamplingRate>1000</SamplingRate>
</INTERNAL_PARAMETER>

Parameter_Type

The value: RTC, TimeStamp, Serial_Number, Product_Number, Assembly_Number, Batch_Number, FW_Major, FW_Minor, FW_Branch, FW_Type, Config_Version_0_3, Config_Version_4_7, Config_Version_8_11, Config_Version_12_15, MCU_Temperature, IMU_Temperature or Mobile_Loop_Status. Required.

Value_Type

Data type of the value: UBYTE, SBYTE, UWORD, SWORD, ULONG, SLONG, ULONGLONG, SLONGLONG, FLOAT32 or FLOAT64. Required.

SamplingRate

Sampling period in milliseconds. Optional. Unsigned short. Default 1000.

InputUID

Optional. Unsigned short. Default 0.

Next steps

To send these inputs onto a CAN bus, with and without recording, see REXGEN XML examples: GNSS, IMU, analogue and RTC data onto CAN. This is the last guide in the reference series. For the list of guides, see REXGEN XML configuration: how it fits together.