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??
