panthripu

panthripu

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Join Date
Mar 2004
Posts
228
Why am i not able to set the time of CPU of siemens S7 PLC. After changing the time , it change automatically to some other time after some time.
Even the checkbox to take time from PG/PC is checked or unchecked.The time goes back to some other time which is running since long.
How to check that from where it is getting this time ?
 
Which S7 PLC, 200, 300, 400 or 1200?

If 300 or 400, go to Hardware Profile, CPU properties and the Diagnostic/Clock Tab, here you set where you syncronise the clock from and at what interval.
 
S7 300/400 CPU time

(If 300 or 400, go to Hardware Profile, CPU properties and the Diagnostic/Clock Tab, here you set where you syncronise the clock from and at what interval. )

I checked and it says none against syncronise the clock from.
The time set in PG/PC is showing the correct time.When i check the checkbox , set from PG/PC , the time of CPU becomes same as PG/PC but after some time goes to default time which was running before.
 
I think the default year is 1994?? unsure. I believe S7-300 and 400 PLC's with MMC memory has a capacitor to keep a charge for the clock to retain the set time.

Unsure how long before it resets.
 
siemens s7 time

No , no ... the time goes back to previous time immediately after some seconds of change.As i mentioned before , the PG/PC time is showing correct time.
 
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