TECHNICAL ASSISTANCE FOR RESTORING THE SIEMENS SIMATC S5 SYSTEM

It is submitted that Siemens Simatic S5 installed at Water Treatment Plant, 415 MW CCP, TPS Guddu is out of service due to its power supply failure on 25/02/2013.

During checking it was found that Power Supply unit 6ES5 955-3LF14 was not working. This unit was repaired & 24V Power Supply restored.

Tried to run the CPU 6ES5 928-3UA12 and reloaded its software from through PG750 so many times but all efforts were in vain.

It is requested to please provide the technical assistance to restore the system.

Thanks

Dear engrwaqas05,

let me first thank you for your very nice report. It's a great help!
A picture often tells more than thousend words.

Forget about yourmissing OB's they are optional and not a must.

Let mewrite down whatI understood from your information.

1. The system was operating fine until there was a problem with thepower supply.

2. The power supply module got replaced.

3. After abackupprogram got loaded with a PG into the CPU.

4. The CPU starts, is not going into STOP, butis giving a stange behavior on some outputs.

Is that correct?

Now we need to do some checks.

If you have a spare CPUit's a good timetoreplace it and see the result. That goes quick.

How much are you fimilar with STEP5? (XREF, monitoring blocks online, status variable table...)

Get theaddress of a "flickering" output.
If possible choose an output which has not effect to the system if we trigger it manually fromour PG (i.e. an output for a lamp).

My German friends marked the outputs with A x.y (A = Ausgang/Output x = Byte number, y = Bit number).

Note it down while we will check now on that output in detail.

Switch the power supply of the system off, wait a few seconds and turn it on again.
While you have a RAM in the CPU the memory of the CPU should be empty.
Switch the CPU to STOP mode and then to RUN.
The CPU should start now (green RUN LED on).
Now go online with the PG and select from the menu "Test/Force Outputs" (or Shift+F5).

Unfortunate I have no CPU here with me so I try to remember.
Enter in the folowwing screen the output byteyou would like to trigger.

QY 2 KM = 00000000(OutputByte 2, 00000000 = Bit 76543210

Now you need to set the output you want to check

Example:

QY 2 KM = 00000001(Output 2.0 is turned on)
QY 2 KM = 10000000(Output 2.7 is turned on)

If the output is turningON and does not "flicker" your backup software has a problem or is not correct. If the output flicker as well the CPU, outputcard or the rack could be defective.

Good luck for your testing!