1747-SDN trouble

We have a piece of machinery with an SLC500 and 1747-SDN module. This morning the PLC faulted due to a problem with the SDN module. When we cycle the power the LED display on the SDN reads 88 (LED test?) but just hangs there and doesn't change. The other weird thing is that the module power and network status LEDs are both off. It's getting backplane power and we checked that the trunkline power at the module is indeed 24vdc. So how could the power LED be off? I'm suspecting that the SDN module is bad but I don't have much experience with Devicenet so if someone could shed some light on this I'd appreciate it!

If the 1747-SDN display shows only "88", then it's stuck in self-test mode. I suspect this is a nonrepairable failure and you need to replace the module.

Well my boss just told me that he ordered a new SDN so I hope you're right! Thanks for your help.

webbyjules said:

I hope you have the scanner programme backed up or you may be in trouble !!

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Fortunately we were able to order it from the OEM and they are going to pre-program it for us. They're charging us about 15% over list price which is well worth it in my mind since we have no way to program it here.