J1939 Protocol Parameter Group Number
The Parameter Group Number (PGN) is the unique identifier of a parameter group. Contains:
- PDU Format determines the format of the message. There are 2 types of PDUFs:
- PDU1 format (<0xF0), is used to send messages to specific nodes (Peer to peer communication).
- PDU2 format, (> = 0xF0) is used to send messages to the entire network of nodes (Broadcast communication).
- PDU specification is dependent on the PDU format.
- If PDUF is PDU1 format, then PDUS is interpreted as the address of the specific device.
- If PDUF is PDU2 format, then PDUS is interpreted as the Group Extension field. This group Extension field is used to increase the number of possible messages to transmit to the network.
PGN is also composed of a Data Page (DP) and Extended Data Page (EDP) bit.
DP is used to expand the maximum number of possible messages for use by other J1939 specifications (ISO 11783 and NMEA 2000).
EDP allows more possible numbers of messages for ISO 11992 Diagnostic (Special Tractor-Trailer Communication).
PGN is a subset of the extended CAN identifier. In addition to the PGN, this extended CAN ID contains the origin address of the message.