Vidmas30 Posted January 20, 2023 Report Share Posted January 20, 2023 Good day, One of our customer's PLC's snap-in module (E4XB) got damaged. It was used for 4AI (4..20mA) measurement (connected 4 sensors) and communication with SCADA system. Recently they tried to change one of the damaged sensors and suddenly all 4 channels stoped working (all MI's attached to particular channels show 16384 values with sensors connected or disconnected). Tried to change hardware settings via jumpers, nothing helps. Question: is there any point to look for some electronic parts damaged on E4XB or it will be just a waste of time and we should just replace with new one? Quote Link to comment Share on other sites More sharing options...
MVP 2023 kratmel Posted January 20, 2023 MVP 2023 Report Share Posted January 20, 2023 Plese check primary and secondary (power) module boards for damaged (burned) parts. Resisor R1 on secondary board and R105-R117 on primary must be checked. Then try to set jamper to 0-10V mode for all chanel and apply test voltage 1....9V to all analog inputs . Result? If voltage mode operate (you see readout) - you can use 500 Ohm resistor connected to analog voltage input and ACM for convert current 0..20mA to 0..10V Quote Link to comment Share on other sites More sharing options...
MVP 2023 Ausman Posted January 20, 2023 MVP 2023 Report Share Posted January 20, 2023 Depending on urgency, I'd be replacing with new, and then investigating the dud unit on your test bench using Kratmel's advice. It will never hurt them to have a repaired spare on hand. BUT, and it's a big BUT (bigger than one belonging to a "famous influencer" 🙂), I'd be very carefully checking all the sensors operations with manual readings on a suitable meter, before reconnecting to the new snap. They've done something seriously wrong to have upset the snap. Check ALL connections are correct, and no other supply fuses are blown that might have been missed. cheers, Aus Quote Link to comment Share on other sites More sharing options...
MVP 2023 kratmel Posted January 20, 2023 MVP 2023 Report Share Posted January 20, 2023 5 minutes ago, Ausman said: They've done something seriously wrong to have upset the snap. Maybe they connect +24VDC power direct to analog input in current mode with 121.5 Ohm inpendance. +-40mA max possible on input. Approx 200mA appear if +24VDC direct connection present = "upset the snap". Quote Link to comment Share on other sites More sharing options...
MVP 2023 Ausman Posted January 20, 2023 MVP 2023 Report Share Posted January 20, 2023 4 minutes ago, kratmel said: Maybe they connect +24VDC power direct to analog input in current mode with "Damage" is such a broad description! If it was mechanical damage then it is quite possible that such a connection, perhaps inadvertently, took place and became obvious after repairs. But I'm betting on human error during the replacement. Connections on snaps can be a bit confusing and lots of attention and double-checking is needed. Quote Link to comment Share on other sites More sharing options...
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