After power on PLC is in red light and switch buttons don't functioning

 Hello and Greetings to all,

I would like to ask for help regarding an error I have encountered during preventive maintenance, I did some cleaning and dusting of the control panel and after the cleaning procedure,I switched the power ON, and the PLC's are in red light and the unit S7-300 is  lighting on "STOP", all of the switch butttons on the control panel are not functioning,  My question is " What could be the possible reason of this type of error? and What should I do to in order to correct this error? hence If I may require, please send on reply, a step by step procedure on what should be done! 

Thank you in advance!

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Split from Please Help With Simatic S7-300 6ES7-315-1AF02-0AB0 With Berger Lahr Sig positec WDM3-004.1801 & VRDM 3913/50 LWB Setup.

StaffSgt.

 Hello and Greetings to all,

I would like to ask for help regarding an error I have encountered during preventive maintenance, I did some cleaning and dusting of the control panel and after the cleaning procedure,I switched the power ON, and the PLC's are in red light and the unit S7-300 is  lighting on "STOP", all of the switch butttons on the control panel are not functioning,  My question is " What could be the possible reason of this type of error? and What should I do to in order to correct this error? hence If I may require, please send on reply, a step by step procedure on what should be done! 

Thank you in advance!

Hello,

Please check the power supply of PLC CPU. How you cleaned the panel/terminals?

Then check the input & out put modules supply. Check for any short circuit at I/O supply. Check for any wire removal or breakage e.g. L+ & M terminals at PLC. This is the primary check. 

If you have step 7, go on line & check PLC diagnosis buffer.

HTH.

Thanks for the reply PISCEAN2010,

I used a dry brush and a vaccum cleaner. Ok I will try all possible actions as you recommend, thank you for the Information and I will reply Immediately for further Inquiries. THANK YOU!

Greetings to all!

I would like to ask for further Information, If I were to set the CPU on MRES,

In What memory am I reseting? does it also reset the error on the modules?

I just want to make sure of the details before I execute the resetting.

This is a follow-up question on the inquiry I made 2 days ago

Im a new user asking for a kind experts advice! 

Thank you in advance!

Hello,

Turning mode selector switch at MERS will reset PLC CPU memory, which in turn will delete program data. Do you have back up of PLC?  Does your PLC has MMC? Or please provide the complete MLFB number of PLC CPU.