How to get M580 Safety IO to use Monotonic communication

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Issue

When making changes to the TOD clock of the PLC, the safety IO will go into fault due to the fact that is uses NTP to sync safe communications.

Product line

Control Expert, Unity Pro, M580 Safety

Resolution

To reset the NTP Sync after a time change, call up %SW128 and initiate a value change from 16#1AE5 to 16#E51A.

To prevent this from happening in the future, you can activate "monotonic" communication.

For the activation of the "monotonic" safe communication system three conditions are mandatory.

The M580 hardware must be at a minimum V3.20 of CPU FW.
The CRA hardware must be at a minimum V2.70 FW. (if used)
The application must have minimum V3.20 of CPU firmware selected in hardware configuration and be built with V15 of CEX minimum

Without implementing these conditions Safety CPU will continue to work with NTP time as a base for safety communication.

If all 3 conditions are fulfilled then safety CPU will work with monotonic time for safety IO communication and be independent from NTP settings and time changes.