Hi @David , thanks for your reply. I know this time stetup.
The problem is that the user claims that this clock is drifting.
They claim that plc developed already 2 hours of delay in 2 months.
As far as I know, when RCT is working correctly this is not possible?

They want to be able to adjust time and I have to solve this problem somehow.

My UNIPI Neuron PLC is running Mervis soft, it is not connected to the internet and there is no NTP server in this network.
PLC is running a scheduler, users are interfacing to controller through modbus TCP.
Users need to be able to update date and time in PLC.

Is it posible to achieve thist by Mervis IDE?