m172 plc system bits

kryunl · ‎2025-05-20

I need to activate the bit when the power is cut off and comes back on in the M172 plc. Is there such a system bit in the M172 plc? I would be very happy if you could help.

FedericoM · ‎2025-05-29

A bit like this is not available, but you can easily create it.

You can set a global variable in the boot task and reset it manually, whenever you will find it at true it means the controller rebooted.

You can also store something in the EEprom at boot, in this way you will save the last start.

If you define a DWORD mapped on MD102.0, this is a variable retained by the lithium battery. It can be written continously. Writing on it Date and Time continously, in the boot task you can read it and save into EEprom when the controller has been switched off.

See Answer In Context

FedericoM · ‎2025-05-29

A bit like this is not available, but you can easily create it.

You can set a global variable in the boot task and reset it manually, whenever you will find it at true it means the controller rebooted.

You can also store something in the EEprom at boot, in this way you will save the last start.

If you define a DWORD mapped on MD102.0, this is a variable retained by the lithium battery. It can be written continously. Writing on it Date and Time continously, in the boot task you can read it and save into EEprom when the controller has been switched off.

m172 plc system bits

m172 plc system bits

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