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Author Topic: Proximity sensor help required  (Read 1415 times)

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Proximity sensor help required
« on: August 19, 2013, 07:49:29 AM »
Can anyone help I have a new PLCM 3 break out board.
I am trying to set up proximity sensors for all axis including homing, the sensor is 6 to 26 volt 300 mA 3 wire NO type.
I am powering using 12 v as this is what was shown in the break out board manual.

When I put volt meter on the terminals on the BOB I only get 1.6 volts when metal is applied I get 0 volt
The led on the mother board works ie goes off when metal sensed.
Mach3 does nothing no screen leds and does not stop motor when metal applied.
Ports and pins are set correctly I am sure.

Can anyone advised me, am i using the wrong size resistance sensor?
Re: Proximity sensor help required
« Reply #1 on: August 19, 2013, 01:26:25 PM »
OK reading all over it seems that I need to add a resistor I am using a PNP NO 6 to 36 volt 300mA sensor can anyone advise what size resistor I should use and where does it go?
Re: Proximity sensor help required
« Reply #2 on: August 20, 2013, 08:38:04 PM »
Well since no one else is jumping in here!  It sounds like you need a pull up resistor to the plus voltage source.  You probably need a couple of milliamps of current at your source voltage.  Use ohms law here: E (voltage) = I (current in amps, a milliamp is 0.001 amps) x R (resistance in ohms)  You can move the terms around so that R=E/I  so for 24 volts and 5 milliamps you'd have 24/0.005 = 4800 ohms or a 5K resistor. Plug in your numbers and flavor as needed!

Gary H. Lucas