CM2904 Instruction Book © 2009 - 2022 Parker-Hannifin Corporation Page 23 of 51
CM2904 Standard software
Messaging
6. CM2904 Standard software
The CM2904 has standard software, which is programmed into module in Parker
production. Software follows the J1939 standard for vehicle communication
network and the functionality comprehends following:
•
Measure and report digital-, analog - and frequency input values
•
Control PWM outputs in frequency, ramp or ON/OFF modes
•
Self-diagnostics and error reporting
6.1. Messaging
6.1.1. General specifications and rules
•
messages are sent repeatedly (if not otherwise defined)
•
in case a message is late or lost (timeout) safety is to be considered
•
CAN messaging is based on the parameter group number field (PGN) (18
bits)
Priority field (P) in the beginning of the identifier should not
be considered by the receiver (3 bits)
Source address field (SA) in the end of the identifier – this
should normally not be considered by the receiver, if not
otherwise defined (8 bits)
•
sender should make sure that the signal is in desired range
•
Receiver should make sure that the signal is in valid range and all diagnostic
functions of signal are in the application.
•
receiver may have additional restrictions for operating range than the valid
signal range in a case the command is outside the operating range
•
signaling by the receiver should be defined if necessary
•
There are two types of signals:
command: desired state for the receiver to take (state or set
point)
measured: measured sensor or internal state, raw or
normalized
6.1.2. Transmission
•
single program cycle in this J1939 application is 10ms
