Codesys Example: CAN Message Watchdog Using CL2 Library

This example demonstrates how to create a watchdog to determine if a CAN message is being received within a timeout period using the low level CL2 CAN libraries. This is often needed to determine if the data is valid or not. For example, RPM can have a valid value of 0 however if the CAN message is not being received it is unknown if the data value of 0 reflects the actual engine RPM. It is important to know the CAN message is being received and the data values are being updated.

The J1939 Message used in this example is PGN 61444 and the message ID will be 0x18F00400. 

The CL2 Receiver function block is used indirectly to determine when a message is received and reset the watchdog timer. When the message fails to be received after the timeout period the PGN message status goes false.

This example applies to both uControl Hydraulic controllers and the OpenView line of displays.

Created in Codesys Version 3.5.20

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