PROFIsafe watchdog timed out.

What does 25 (PROFIsafe Watchdog) mean?

The PROFIsafe watchdog timer has expired, meaning the safety communication between the I/O module and the Safety PLC was not received within the expected timeframe. This indicates a loss of safety communication and will halt safe operations.

• Intermittent loss of communication packets on the PROFIsafe network due to cable issues (e.g., damaged RJ45 connector, broken conductors, loose shield connection).
• Excessive network load or latency causing PROFIsafe telegrams to arrive later than the configured watchdog time (F-monitoring time).
• A temporary power dip or reset of the I/O module or Safety PLC, causing a brief communication interruption.
• Incorrectly configured PROFIsafe F-monitoring time (watchdog time) in the Safety PLC or I/O module parameters, set too low for the actual network conditions.
• Malfunctioning PROFIsafe communication controller on either the I/O module or the Safety PLC leading to delayed or lost telegrams.

Click steps to track your progress.

1. 1

   Inspect all PROFIBUS/PROFINET cables and connectors (e.g., X1, X2 ports) between the Safety PLC and the I/O module for damage, looseness, or improper shielding.

2. 2

   Analyze network traffic and overall bus load using a network analyzer to identify excessive data volume or communication delays affecting PROFIsafe telegrams.

3. 3

   Verify the configured F-monitoring time (PROFIsafe watchdog time, e.g., Parameter F-MON) in the Safety PLC's safety program or I/O module's configuration matches the network's expected performance, potentially increasing it with careful risk assessment.

4. 4

   Temporarily power cycle the I/O module and the Safety PLC to reset their communication interfaces and clear any transient states.

5. 5

   Check for and address any other communication errors (e.g., 'PROFIsafe communication error' Code 20) that might be preceding the watchdog timeout, as they could be root causes.