Hi all,
I'm using a CNC table as a tack welder.
Problem is, the targets under the weld head can be uneven heights, which throws off ideal pressure.
I'm trying to use the G31 straight probe command in conjunction with a photo switch to find the ideal surface each time.
There is a gauge on the moving weld head that has a rod that moves up or down according to how much pressure the head is exerting on the work surface.
There is a mechanical switch on a bracket on the head that is tripped when this rod moves too high; I was using it as a Z axis limit switch.
It is connected to pin 10 and was configured as an EMO active low trigger.
For prototyping this concept, I've co-opted this switch.
I've reassigned pin 10 as a probe input from within the Config/Ports & Pins/Input Signals menu. It activates on an active low.
I measure +4.8VDC across the switch, so I know the port input has a pullup resistor.
My program tells the head to go to a low point past where I know the switch would trip, using a slow G1 Z -x command. Fast moves throw off the trip point too much.
It works the first time. The head moves down, the switch trips, and I have ideal pressure.
From that point forward, the G31 command completely ignores both the switch and my G code commands to send the head to a low point. Instead, it uses the Z position it first captured as the new Z endpoint for all Z plunges and proceeds to try to weld everything at that point.
What's happening here? What command do I need to issue to reset the G31 parameters so that it seeks a new trip position each time?
- George
I'm using Mach3 v. R2.63 on a Windows XP machine using a motherboard parallel port to communicate with the CNC Amp.
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