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Wiring of Allen Bradley Touch button

Wiring of Allen Bradley Touch button

Wiring of Allen Bradley Touch button

(OP)
Hello,
   I currently have a european machine that has 2 touch buttons(Palm Buttons)made by Allen Bradley that activate a cycle.This touch button has a 5 pin qd connector the pins are as follows.
pin 1 Positive DC wire
pin 2 N.C white wire
pin 3 Negative DC wire
pin 4 N.O black wire
pin 5 (Common)

This sensor puts out a 3 Amp 24DC Output

The PLC is a PNP.The signal comes through Pin 4.
This Palm button signal is a electromechanical relay.I have found high failure rate on these switches.So I investigated.I found this switch is rated for 200,000 cycles.I have exceeded this in 6 months of operation.So I purchase a Allen Bradley touch button(same series) with a solid state output.Rated for 50 million cycles.The only difference in pin configuration was there was no pin 5 (Common)on the solid state output ab switch.The other difference was the Output signal on the solid state switch.It was 800ma 24DC .I figured since the plc was still recieving the +DC input it would be fine.I figured pin 5 was just a european grounding difference.It had no relation to the PLC receiving it's input.I was wrong.The new Transitor switch powers up and says that it is giving a output as shown to me on the touch button indicator.The PLC however does not show a input on the controller.I did not have a meter ready so I could not test for voltage.Upon Investigation I found that Pin 5 on the "old mechanical relay switch" that on the switch itself said Common  was supplied by a branch of + DC circuit.So I dissconnected Pin five wire on the "old mechanical relay switch and I got the same results as the solid state switch.
  My question is is what is pin 5 Doing that I am missing.I do not think it is PLC related 3A DC output on the old switch versus 800ma Output Dc on the new transitor switch.I proved this out by disconnecting pin 5 from the branch dc circuit on the old switch with same results.I have contacted Allen Bradley on this issue and followed up but still no response??
     Thanks,
        Servo

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