Internet PLC Forum
General => Technical support => Topic started by: jbrandall on January 20, 2013, 05:01:31 PM
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Is there something special with input #4 on the FMD 16-16? I recently purchased 3 boards and have tried to use 2 of them with the same results: I have two 3 wire normally open NPN proximity sensors hooked to inputs 3 and 4. When I power up or reset the plc, if the sensors are on, input 3 works as it should, however, input 4 does not. Both sensors indicate that they are on, and the #3 led and the #4 led are lighted on the board. However, in monitoring mode, input #4 does not show up as on, but #3 does (as it should), nor does my program function properly. Moving the sensor away from it's target and back corrects the problem, but this is not acceptable as sensors #4 is supposed to be on at startup and any of the other sensors could be on then. I switched sensor wires, and the problem is still at input #4.
The sensors and the program worked on a Nano1, but I needed more inputs and outputs so I upgraded to the FMD 16-16. I set the first FMD aside when it didn't work and tried the second. Any suggestions on testing the third board without installing my programs on it? Any other suggestions??
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Did you define HSC #1 or PMON 1 or 2? These special inputs maps to inputs 3 & 4 If you did then the inputs will no longer function like a digital input.
Try to load in a blank program into the PLC and reset it, then try to trigger input 3 & 4 and see if you are able to read the input status correctly on i-TRiLOGI online monitoring.
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Ah yes, I did a PMON 2. Silly me to think that referred to input #2! Thank you, I think I can handle it now.