I have a conveyor belt that has a photo electric sensor on the bottom drum this causes me no end trouble, in the panel there is a + & - onto the sensor then there is a third wire used to give the pulse message from the sensor to the PLC so i cannot just take it out as it stops the machine, is there something i could use that would give me permanent on/off pulses so i could wire this in place and trick the PLC into thinking there is a motion sensor in place?

  • \$\begingroup\$ I wouldn't do that. The motion sensor is most likely there for safety. If you feed the PLC a fake signal, then you will defeat some kind of safety measure and make your conveyor dangerous to work around. \$\endgroup\$ – JRE Nov 10 '15 at 10:03
  • \$\begingroup\$ the conveyor feeds another conveyor in which has a fill level sensor what used to happen was the first fill level would pull a ram back on the shredder the second fill level would stop the conveyor belt and you would need to reset the shredder and start it again. \$\endgroup\$ – Dale Nov 10 '15 at 10:16
  • \$\begingroup\$ This was no good so whilst we had the engineers here setting it up and the machine was still under warranty they adapted the program so that once the max fill level was reached it would not stop the conveyor and only pull the ram fully back then release the ram once fill sensor is clear so the sensor in question is no longer needed as that was it sole purpose and was overseen when these adaptions were made now the machine is out of warranty so to get the engineers back will cost especially to start messing with the program, i was thinking of something along the lines of a recycling timer? \$\endgroup\$ – Dale Nov 10 '15 at 10:16
  • \$\begingroup\$ Good grief : Contact the manufacturer and get the thing fixed properly by them. You really don't want to incur possible liability for your company. Sometimes the smart thing to do costs more. \$\endgroup\$ – Marla Nov 10 '15 at 15:08

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