For times like this, I have a removable fuse or circuit breaker just upstream of the main plc power input.  I pull the fuse lever to open, or open the circuit breaker.

I then wait 30 seconds, and reset the power back to on.

This works 90+% of the time for me. 

viren.vadgama

Hello everyone,

I have S7 1200 series 1214C DC/DC/DC PLC. Some problem generated inside PLC so right now PLC RUN led on,Error and mint led blink.Than i was planed to reset PLC but PLC not detected in my system.System IP is perfect,set pg/pg connection perfect and LAN driver is working properly.

Now tell me your suggestion.What can i do for short out this issue.

Would you please explain how you determined this?  Flashed the firmware over top of it and suddenly it started working?

I do not recall that working other than when the firmware was buggy causing the downloaded project to become buggy.

By doing a factory reset, it usually fixed that problem.

However, if you updated to a newer firmware and the problem went away, or you updated to a newer portal service pack / update, or replaced the plc, any of these may also fix these strange problems.

I really would like to know since we have somewhere around 100 s7-1x00 installs and still growing.

viren.vadgama

Thank you so much for your response.

Finally problem is rectified. PLC firmware was corrupted. 

Thanks.