GSV WallClockTime jumped an hour and our shift report lied
The question
ControlLogix, GSV of WallClockTime into a UDT, DST happened, batch records shifted. NTP is 'someone else's job.' Do you freeze PLC time to UTC and convert in the historian, or keep local and eat the DST fight?
TS ControlsThe answer
UTC in the processor. Convert at the historian and the HMI. DST in a PLC is how you get a two-hour hole or a duplicate batch ID. Pin NTP to a plant source, not a laptop. If you must stay local, disable DST on the controller and document it in the SOP so the next guy doesn't 'fix' it.
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