CAN Transmit

Overview

The CAN Transmit Tab provides a way to send out CAN messages that contain values from channels or special values such as firmware version or setup name.

Messages

Adding or Removing Messages

Towards the bottom right of the Messages Table, use the button to add a new message, and the button to remove the selected messages(s).

Messages Table

Tx

Enables the message. IF unchecked then the message will not be sent by the display.

Message

Name of the message.

Rate

Rate at which the message is repeatedly sent.

ID

The CAN ID. This is specified as the right most 11 bits of a 16 bit value or the right most 29 bits of a 32 bit value for extended IDs.

If the Show CAN IDs as Hexadecimal box is checked, the IDs are shown and entered as hexadecimal numbers with an 0x prefix. Otherwise, they are shown and edited as a decimal number.

Clicking on the header at the top of this column will sort the table by CAN ID.

If the number has 3 hexadecimal digits then it is a standard ID, if it has 8 hexadecimal digits then it is an extended ID.

When entering CAN IDs into this column, use the ‘S’/‘E’ button to switch between standard or extended.

Note that an extended ID with the same value as a standard ID is NOT the same message and will not receive messages of the other ID type.

FD

Makes this a CAN-FD message. In FD mode, higher start bit values are possible. CAN-FD enabled CAN ports only.

BRS

For CAN-FD messages, sets the Bit Rate Select flag. CAN-FD enabled CAN ports only.

DLC

Specifies the Data Length Code of the channel, i.e. the size of the data packet of this ID in bytes. This can be anywhere between 0 and 8 bytes; by default it is set to the maximum size of 8 bytes. For CAN-FD messages this can go up to 64 bytes.

Wait For All

If the Wait For All column is ticked, then the CAN message will only be transmitted once all the inputs to the message (see below) are valid. Inputs such as analogue channels are valid immediately but for data coming via CAN or serial, the outputs are not valid until they have been received at least once.

If the Wait For All column is not ticked, then the message will be transmitted immediately; any sections of the message where the inputs are not valid will be zero.

Signals

Adding or Removing Signals

Towards the bottom right of the Signals Table, use the button to add a new signal, and the button to remove the selected signal(s).

A message must be selected in the Messages Table to be able to add signals.

Signals Table

Channel

Channel that will be packed into the CAN signal.

Type

Data type and byte order for the raw signal value. The data type affects the size of the signal.

Some data types are special and do not require a channel (e.g. Display Serial Number).

Position

Byte position of the first byte in the CAN frame that the signal occupies

Scalar

Scalar used to convert the Physical Channel value to a raw value. This is specified as if converting from raw => physical.

Phys = (Raw * Scalar) + Offset

i.e. Raw = (Phys - Offset) / Scalar

Offset

Offset used to convert the Physical Channel value to a raw value. This is specified as if converting from raw => physical.

Units

Units of the Physical value. If the input channel uses different units then Dash Design will insert additional scaling to convert from the Channel units to the Physical units prior to applying the Scalar and Offset.