392 Properties of the Modules
imc CANSAS Users Manual - Doc. Version 1.9 - 05.12.2014© 2014 imc Meßsysteme GmbH
Channel structure:
1. Nibble of the SENT message: Status and Communication
nibble
Reserved for specific application
Reserved for specific application
= 1 CRC of message valid
= 0 CRC of message invalid
Attention! The message with the FAST channels is transmitted after each SENT message, even if the
SENT message’s CRC is not valid. However, in such a case be absolutely certain to observe bit 8 of the
Status channel, since if the CRC is invalid, all of the CAN-message’s other bits can also be incorrect!
Example: The value 472 is transmitted in the Status channel. This corresponds to 1D8H. Thus,
Message start is set to 1; the CRC is DH = 13 and CRC valid = 1. All others are 0.
Use of serial protocol
No serial protocol: There is no serial protocol in the SENT message. Or, there is one, but it is not to be
evaluated.
Short serial protocol (8 Bit): The sensor uses the short serial message format. Its data field is 8 bits
wide.
Enhanced serial protocol (12 Bit): The sensor uses enhanced serial message format. The configuration
with a 12-bit data filed is used.
Enhanced serial protocol (16 Bit): The sensor uses enhanced serial message format. The configuration
with a 16-bit data filed is used.
If a serial protocol is set, a CAN message is generated which contains both the serial protocol’s data
field and its message-ID. The corresponding channels in the CAN message are called _SerialControl
(message.ID) and _SerialData (data field).
If the setting for this parameter does not fit the actually received SENT messages, the following
adaptation is performed: if the data filed is actually wider than configured, the top bits are truncated.
If the data field is actually smaller than configured, the top bits are stuffed with zeroes. If a serial
protocol is defined, but none is actually received in the SENT messages, then no corresponding CAN
messages are generated. If the serial protocol is not configured, but actually received in the SENT
messages, it is ignored.
If a CRC error occurs in the evaluation of the serial protocol transferred in the SENT messages, the
serial protocol affected is rejected and not transmitted on the CAN-bus.
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