PGN

A parameter group is a set of information that has a common context and thus shares the same transmission rate. Each parameter group is identified by a unique number – the Parameter Group Number (PGN). The parameter group is easily confused with the CAN identifier. The purpose of this chapter is to explain the difference between a J1939 parameter group and a CAN message identifier. The following comparison presents the commonalities and differences:

Commonalities:

• Grouping of signals with identical or similar context
• Can be identified by a unique number
• Contains application and protocol data

Differences:

• Not limited to 8 data bytes (upper limit of 1785 bytes)
• Can be transmitted point-to-point
• The priority of the message is independent of the PGN

If a data length of more than 8 bytes is defined for a parameter group, this will be sent as a multi-packet message. The standard provides a so-called transport protocol.