I'm re-building a Novakon NM-145 milling machine. It uses proximity sensors for homing and limits. The sensors are:
NPN
Normally Open
6-36 volt
200mA
I've started with the proximity sensor on the Z axis. The output goes to pin 15 on a CNC4PC C11G BOB. The sensor is wired as indicated in this figure from the C11G manual (see attachment).
I'm using a 10K ohm resistor for R1. When the sensor is activated by a piece of metal the LED below pin 15 goes out, there is a small LED that comes on at the sensor and the red LED on the sensor glows brighter. In Mach3, in the diagnostic window, M3 Home goes from yellow to brown. A voltmeter across pin 15 to ground on the BOB reads 5.83V when the proximity sensor is not activated and goes to 0.00V when the sensor is activated. Power supply to sensor is 12 volts.
When I jog the Z axis to either end of its travel the proximity sensor is triggered but I can continue to jog the axis beyond this point. Similarly if I home the Z axis in Mach3 it will activate the sensor but continue moving until I hit Reset in Mach3 or Press the E-stop button on the machine. Changing the configuration for Z Home in Mach3 to active low has no effect other than to change the colors of the LEDs for M3 Home on the diagnostic page of Mach3. Now it is brown when off the limits and yellow when the sensor is triggered.
I think I’m missing something simple here but I’m just not seeing it can any of you folks give me some insight as to what the problem might be? Thanks for any help you can provide.
Curtis