I have a Siemens S5 CPU 928B with a main rack and 3 remote racks. The plant is stopping without any alarms or fault indication. You can go to the SCADA and start the plant again. This is a happening at any time. The plant can run for 6 hour and at some times it happen every 20min. PLC do not go to a stop mode.
My program is looking at one HP fan that has to run all the time. The interlock is using an always on bit (F1.0) that is generated in OB1. This fan keeps on stopping without any req. to stop.
This program is working for the last 10Years.
I have done the following to try eliminated it without any success
Change power supply’s at all the racks.
Install new 24V field power supplies.
Replace all Input and Output cards.
Replace IM cards.
Change CPU.
Record all power 24V and 220V all OK
Insert DB1 (For hardware Setup)
Make sure that all error OB is removed
Only OB in program are OB1 an OB20, OB21 and OB22
Can someone give me any suggestions that I can do to try to eliminate it?
My program is looking at one HP fan that has to run all the time. The interlock is using an always on bit (F1.0) that is generated in OB1. This fan keeps on stopping without any req. to stop.
This program is working for the last 10Years.
I have done the following to try eliminated it without any success
Change power supply’s at all the racks.
Install new 24V field power supplies.
Replace all Input and Output cards.
Replace IM cards.
Change CPU.
Record all power 24V and 220V all OK
Insert DB1 (For hardware Setup)
Make sure that all error OB is removed
Only OB in program are OB1 an OB20, OB21 and OB22
Can someone give me any suggestions that I can do to try to eliminate it?