AC Input Node Issue

I am having an issue with a Automation Direct 110V AC Input Card(D2-16NA). This is connected to a Automation Direct D205 CPU. I am experiencing an Input Node failure. I am on my third Input card in the last month. This is on my safety circuit which contains 7 solid state switches. The backplane seems fine and I do not see any cracks in the switches. Has anyone come accross a similar problem?

Regards

Check the backplane receptacle where you plug in the input card. It has happened that a little piece of paper or lint gets jammed into one of the pin positions and intermittently blocks it. Those intermittent problems are a pain.

I once was in a computer troubleshooting class where the instructor deliberately stuck a piece of paper on one of the card connectors, and challenged the class to troubleshoot the PLC. Boy I will never forget that one.

Make sure that your voltage is not being spiked by the switching of the solid state switch or other parts of the circuit. The inputs on that card are rated for 130 Vac max anything above that and it pops.

Most siemens and ab modules have built in spike protection into the module. The AD modules do not.

I checked the backplane yesterday and everything looked fine. I am going to order a backup so I can change out the next time it happens.

I am also having our Maint. Dept. go thru and check all of the switches to ensure we are not getting any spikes or shorts.