Compact Logix L30ER Date & Time Issue.

Hi guys,

I am facing a weird issue with an L30ER. When power is cycled to the controller,
the Date & Time changes to some other value & then reverts back to the correct Date & Time. At least this is what I am thinking is happening.

Trying to capture the Date & Time values using the First scan bit has not been successful with the correct date & time captured.

I was only able to deduce what is happening because of a time dependant logic was getting triggered on a power cycle. I have attached a screenshot of the logic.

Does your GSV Instruction run before your screen is executed .?
In my case GSV is the first instruction to be executed and before the rest of them.

I suspect widelto has the right of it. Your DateTime array does not directly hold the current controller values; it holds the date/time as of when the GSV was run last to collect those values.

Obviously the GSV does not run while the controller is off or otherwise not in run mode. From when you first power up until the GSV is executed DateTime will maintain the values from before you cycled power.

(As a side note, you can use this discrepancy to programmatically check how long the PLC was down for).

widelto said:

Does your GSV Instruction run before your screen is executed .?
In my case GSV is the first instruction to be executed and before the rest of them.

Click to expand...

Yes the GSV is the first instruction to be executed.

Would it make any difference if the GSV is in the main routine ?

plvlce said:

I suspect widelto has the right of it. Your DateTime array does not directly hold the current controller values; it holds the date/time as of when the GSV was run last to collect those values.

Obviously the GSV does not run while the controller is off or otherwise not in run mode. From when you first power up until the GSV is executed DateTime will maintain the values from before you cycled power.

(As a side note, you can use this discrepancy to programmatically check how long the PLC was down for).

Click to expand...

But the interval between the power cycle is not much, maybe 2 to 3 minutes & max is 10 minutes.

We have another L30ER running the same logic & on the same firmware version without any trouble.

Yacineg said:

Would it make any difference if the GSV is in the main routine ?

Click to expand...

It should not, as long as the GSV runs before the DateTime values are used anywhere.

Can you post a pic of your GSV rung?

Yacineg said:

But the interval between the power cycle is not much, maybe 2 to 3 minutes & max is 10 minutes.

Click to expand...

If you are only using time to determine shift, then running GSV afterward would only cause an issue if machine was down across shift change. It doesn't sound like that's the cause then.

Yacineg said:

We have another L30ER running the same logic & on the same firmware version without any trouble.

Click to expand...

Interesting.

When it powers up with the incorrect time/date, is it always the SAME time/date?

If yes, do you have a nonvolatile backup installed and set to load on program loss?

Another thing to look at is in the controller properties if you have time synchronization enabled and (if so) if the PLC is the master.

The GSV rung is the first rung to be executed. See attached picture.

I have not been able to observe the Incorrect Date/Time on power up.

There is no nonvolatile backup installed, time synchronization is not enabled.