ET200S Safety Module Failure

Hi all,

This is my first post on this forum for some time. Its nice to be back.

We have been having repeating failures on our ET200S modules and as far as i can remember they are all safety modules. It is simply a case of replacing the module to solve the issue but i was wondering what is the mean time to failure of the safety modules compared to the usual modules which (touch wood) have been far more reliable. Could it be the supply to the rack?

Cheers all

bmw_apprentice

Siemens will publish data on MTTF for use in calculating performance level in respect of the new (again delayed) safety standard 13849 but it sounds like you have another problem other than general reliability.

Check the loading on the card, the earthing, could anything be generating static that is discharging through the card?

Nick

Cheers for the response.

Thinking about it there is definately a possibility of static build up. I will check the earthing at the next opportunity. Is there any reason this would affect safety modules in particular?

bmw

Are these the 30mm wide 4 DI-F or 4 DO-F Profisafe modules? The DI-F modules are looking to receive the precise voltage that they output, and I have seen poor wiring give intermittent faults with these.

Are you sure the modules are permanently failing, as I have had a couple of instances recently where the SF light has come on, no fault has been seen in the diagnostic buffers, and just unplugging and reinserting the module has reset it.
I am yet to find a cause, but am hoping that it is a wiring fault which will develop a bit further so we can actually find a root cause.

Please keep us updated with your problem.

Phill

Hi,

what kind off faults have you had with the safety modules. In my project I had to extend the F-monitoring time in HW config to prevent losing the modules from time to time. But of course safety first.

Hi,

Yes i am referring to the 30mm wide modules. The faults are not intermittent the modules just seem to fail. No lights come on the actual module at all but the rest of the rack is put into fault (obviously). All it takes is a replacement of that particular module and all is ok. A fault is seen in the diagnostic buffer on that node. We tried simply swapping this module for the one next to it to see if a power cycle on the module itself worked, it didnt.

I will check the wiring tonight and also rig up a test for the failed one. If it comes to it ill send all the failed ones to siemens with a request for what has caused them to fail.

Cheers all

bmw

I had some profibus et200 modules they weren't safe modules mind you. Would go into error and the only way was to cycle the power. They were revision 3 or made in 2004. In the hardware diagnosis it was as if they had just dropped of the bus and wouldn't reconnect.
I eventually replaced them with rev 5 or 2009 modules with the same installation and nothing has gone wrong since. I didn't even turn the power off the rest of the machine when replacing the modules and they re established comms and cleared the SF error so the old ones had to lose power to reset themselves.
Weird but a little birdie told me siemens had a problem with rev3 modules although they would never admit it.
I too checked voltage , earth spikes etc.