For all you S7 guru's (again)

We have

2 X S7 417H Prcessors on two racks set up for redundancy
2 X CP443-1 communications modules (1 on each rack)

When we power up the left hand power supply the whole rack gets powered up i.e. both plc's and both comms modules. All the LEDs on the processors come on and the comms modules look more or less normal. If the right hand power supply gets powered up on its own all the LEDs on all the modules flash. We have set up this configuration before and have never seen this situation.

We have swapped the power supplies but the symptoms remain the same.

Starting to think rack problems.

Any ideas guys ??

Barry

Just an update

We left out the right hand power supply and both processors seem to power up normally ??

When we set up this configuration before (on another project) I seem to remember that each power supply fed each individual processor.

Barry

Barry which Rack are you using?


Nick

And, is this a new installation ?
Or did it used to work ok and then problems started ?

Try replacing the back plane. I have seen a few shorted out.

We are trying to use both racks. It just seems strange that both racks get powered by one supply.

This unit was supplied to us by the client to do FAT (Factory acceptance testing) for a project that is replacing an old AB PLC2 system. I think it is a second hand unit that has been superceded.

We have asked the client for a replacement rack so we will see how we go.

Barry