REXGEN XML reference: recording (SD) and USB outputs

Choose what the logger records, when recording starts and stops, how files are split and what streams live to REXDESK over USB.

Recording blocks at a glance

The "SD" in these element names is historical. Every REXGEN logger records to internal storage (eMMC). There is no card to insert. Recording uses two kinds of block:

• SDINTERFACE is the recorder: file size and length, triggers, pre and post-trigger time. The schema allows up to four.
• SDMESSAGE names one thing to record and the SDINTERFACE that records it. Add one for each message or sensor block.

If the file has no SDINTERFACE, the logger writes nothing to storage. Live data over USB works the same way: one USBINTERFACE and one USBMESSAGE for each stream. Every block takes a UID attribute (required and unique in the file) and the optional Version, X and Y.

Each entry in the settings lists gives the meaning, then whether the schema requires the element, its type and its default where one exists.

Recorders (SDINTERFACE_LIST)

SDINTERFACE

This recorder records from power-on, starts a new file every 100 MiB or every hour and keeps no pre or post-trigger data.

<SDINTERFACE UID="2">
  <MaxLogSize>104857600</MaxLogSize>
  <MaxLogTime>3600</MaxLogTime>
  <LogFormat>InfluxGeneric1</LogFormat>
  <PreLogTime>0</PreLogTime>
  <PostLogTime>0</PostLogTime>
  <IsPostTimeFromEnableStart>true</IsPostTimeFromEnableStart>
  <NumberOfLogs>0</NumberOfLogs>
  <IsEnableCreateNewLog>false</IsEnableCreateNewLog>
  <InitialEnableState>true</InitialEnableState>
  <EnableUID>0</EnableUID>
  <DisableUID>0</DisableUID>
  <PartitionID>0</PartitionID>
</SDINTERFACE>

MaxLogSize

Maximum size of one log file in bytes. When a file reaches it, the logger starts a new file. For example 104857600 (100 MiB). Required. Unsigned int.

MaxLogTime

Maximum duration of one log file in seconds. When a file reaches it, the logger starts a new file. For example 3600. Required. Unsigned int.

LogFormat

File format of the log. The only allowed value is InfluxGeneric1. Required.

NumberOfLogs

Maximum number of log files the logger creates. 0 means no limit other than the storage. 1 means a single file. Required. Unsigned int.

InitialEnableState

true records from power-on. false waits for the event named in EnableUID. Required. Boolean.

EnableUID

UID of the block whose event starts recording, for example a trigger. 0 means none. Optional. Unsigned short.

DisableUID

UID of the block whose event stops recording. 0 means none. Optional. Unsigned short.

EnableUID_LIST, DisableUID_LIST

Several start or stop sources, each an EnableUID or DisableUID child. The example files do not use them. Optional.

IsEnableCreateNewLog

true starts a new file each time recording is enabled, so every event gets its own file. Required. Boolean. Default false.

PreLogTime

Milliseconds of data from before the enable event that the logger keeps in the file. 0 means no pre-trigger data. Required. Unsigned int.

PostLogTime

Milliseconds the logger keeps recording after the trigger. Required. Unsigned int.

IsPostTimeFromEnableStart

Where PostLogTime is counted from: true from the start of the enable event, false from its end. Required. Boolean.

PostLogContinuous

When true, recording continues past PostLogTime until a size, time or other limit stops it. Optional. Boolean. Default true.

PostLogOnlyOnEnable

When true, post-trigger recording happens only when recording was explicitly enabled, not in always-on recording. Optional. Boolean. Default false.

PartitionID

Storage partition to write to. The main partition is 0. A value above 0 needs storage formatted with partitions. Use 0. Required. Unsigned byte.

How pre and post-trigger time work together

When a trigger enables recording, the logger first adds PreLogTime of buffered data from before the event. It then records through the event and keeps recording for PostLogTime. IsPostTimeFromEnableStart moves the start of that post-trigger count. IsEnableCreateNewLog puts each event in its own file.

The triggers themselves are easiest to build in REXDESK. See REXDESK: start and stop logging with triggers.

What to record (SDMESSAGE_LIST)

SDMESSAGE

Each SDMESSAGE records one block through one recorder. This one, from ADC2CAN_SD.xml, records analogue input block 8 through recorder 2.

<SDMESSAGE UID="18">
  <MessageIdentStart>0</MessageIdentStart>
  <MessageIdentEnd>4294967295</MessageIdentEnd>
  <Direction>OutputPeriodic</Direction>
  <DLC>8</DLC>
  <IsExtended>false</IsExtended>
  <InterfaceUID>2</InterfaceUID>
  <Period>0</Period>
  <TriggeringMessageUniqueID>0</TriggeringMessageUniqueID>
  <DefaultHex>0000000000000000</DefaultHex>
  <InputMessageUID>8</InputMessageUID>
</SDMESSAGE>

InputMessageUID

UID of the block to record: a CANMESSAGE, an analogue, IMU or GNSS block. Required. Unsigned short.

InterfaceUID

UID of the SDINTERFACE that writes it. Required. Unsigned short.

Period

Period in milliseconds. Every example sets 0. Required. Unsigned int.

MessageIdentStart, MessageIdentEnd

Required by the schema and ignored by the logger. Filter CAN identifiers on the CANMESSAGE instead. Use 0 and 4294967295. Unsigned int.

Direction

Required by the schema and ignored by the logger. Use OutputPeriodic.

DLC

Required by the schema and ignored by the logger. Use 8. Unsigned byte.

IsExtended

Deprecated, still required by the schema. Use false. Boolean.

TriggeringMessageUniqueID

Required by the schema and ignored by the logger. Use 0. Unsigned short.

DefaultHex

A default payload, two hexadecimal digits per byte. The examples set 0000000000000000. Optional.

Live data over USB (USBINTERFACE_LIST and USBMESSAGE_LIST)

A USBINTERFACE enables the USB live view, which REXDESK uses to show data while the logger is connected. The schema allows one. It works on models with a USB PC connection: REXGEN 1, REXGEN 2, REXGEN 2 IMU GNSS and REXGEN Air with the factory USB option.

USBINTERFACE

The block has no children, only its attributes.

<USBINTERFACE UID="3"/>

USBMESSAGE

Each USBMESSAGE streams one block. This one, from ADC2CAN_SD.xml, streams analogue input block 8.

<USBMESSAGE UID="20">
  <MessageIdentStart>0</MessageIdentStart>
  <MessageIdentEnd>4294967295</MessageIdentEnd>
  <Direction>OutputPeriodic</Direction>
  <DLC>8</DLC>
  <IsExtended>false</IsExtended>
  <InterfaceUID>3</InterfaceUID>
  <Period>0</Period>
  <DefaultHex>0000000000000000</DefaultHex>
  <InputUID>8</InputUID>
</USBMESSAGE>

InputUID

UID of the block whose data the logger streams, for example a CANMESSAGE or an analogue block. Required. Unsigned short.

InterfaceUID

UID of the USBINTERFACE. Required. Unsigned short.

MessageIdentStart, MessageIdentEnd

Range of CAN identifiers to stream, in decimal. 0 to 4294967295 streams everything. Required. Unsigned int.

Direction

Input, OutputEvent or OutputPeriodic. The example files use Input for a CAN message and OutputPeriodic for sensor values. Required.

Period

Transmit period in milliseconds, used only with OutputPeriodic. Required. Unsigned int.

DLC

Data length of the message. The examples set 8. Required. Unsigned byte.

IsExtended

Deprecated, still required by the schema. Use false. Boolean.

DefaultHex

A default payload, two hexadecimal digits per byte. Optional.

Putting it together

To record a sensor and stream it, name the sensor block's UID in an SDMESSAGE (record) and in a USBMESSAGE (stream). To send it on the bus as well, name it in a CANSIGNAL too. The "with recording" example files do exactly that. See REXGEN XML examples: GNSS, IMU, analogue and RTC data onto CAN.

To get the recorded files off the logger, see REXDESK: download and export your logs.

Next: REXGEN XML reference: CAN interfaces and bit timing.