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Author Topic: Proximity sensor is activated at limits but axis movement doesn't stop  (Read 2363 times)

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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
Re: Proximity sensor is activated at limits but axis movement doesn't stop
« Reply #1 on: August 29, 2014, 07:37:08 PM »
I've attached the xml file. I should add that with soft limits set up in Mach3 the axis all stop appropriately when jogged.

Curtis
« Last Edit: August 29, 2014, 07:41:01 PM by Krenovian »

Offline Hood

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Re: Proximity sensor is activated at limits but axis movement doesn't stop
« Reply #2 on: August 31, 2014, 04:21:23 AM »
You do not have any limits or home switces set in Mach except Z Home.
You will need to enable them and tell Mach which port and pin they are connected to.
Hood
Problem Solved
« Reply #3 on: September 10, 2014, 12:09:43 PM »
The problem was more my lack of understanding of how Mach3 worked with my machine. If I pressed the ref all button the Z axis would stop when the proximity sensor was triggered. I could jog the axis manually and continue beyond this point so I thought there was a problem with my configuration of Mach3 or the wiring of the machine. Because the machine has only one proximity sensor at one end of each of the x and y axis, soft limits must be used. The original configuration of Mach that came with the machine had only X,Y, and Z home activated in Mach3 and was configured so soft limits was persistent. Once I figured this out everything is functioning appropriately.

Thanks for your input HOOD I appreciate it.

Curtis