Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: grsabourin on January 29, 2019, 10:18:38 PM

Title: Touch plate + touch probe connection
Post by: grsabourin on January 29, 2019, 10:18:38 PM
Hi

I already have on my machine a touch probe. I would like to add a touch plate to automatically measure tools. The touch plate needs to generate a probe event.  My question if the probe input is already occupied by the touch probe, where I can connect the touch plate to generate a probe event when I measure the tools

Thank you
Title: Re: Touch plate + touch probe connection
Post by: Peter Homann on January 29, 2019, 11:09:11 PM
Wire the 2nd touch plate in parallel with the first so it activates the same probe input.
You then need a separate different button to activate a tool measuring macro, rather than the z-axis touch off macro

Cheers
Peter
Title: Re: Touch plate + touch probe connection
Post by: grsabourin on January 29, 2019, 11:11:59 PM
I have tough about this solution but I was wondering if there are an other solution. I still have available space on my input board
Title: Re: Touch plate + touch probe connection
Post by: MyGarageShop on February 01, 2019, 09:36:48 AM
I have 2 connections to my probe input. As long as both are not active at the same time I do not see why you cannot do this also? I hope this helps.
Title: Re: Touch plate + touch probe connection
Post by: grsabourin on February 01, 2019, 06:23:35 PM
 It is what I would like to do but I never saw a second input for a probe. What is the name of th second input you use?
Title: Re: Touch plate + touch probe connection
Post by: joeaverage on February 01, 2019, 11:17:40 PM
Hi,
Mach3 has only one probe input.

You could dedicate another spare input as another probe signal but it will be too slow.

The current (one and only) probe input is a real-time input. Thus Mach decelerates/stops  the Z axis within a few usec of receiving
a probe signal ie very quickly or 'realtime'. A normal input would be signaled back to Mach from your motion controller
(either parallel port OR external controller) but it will take up 10-12 msec. Mach would then have to issue a decelerate/stop
command to the Z axis and therefore another delay of 10-20 msec. The total delay could be anywhere up to 40 msec.

If you probed very VERY slowly you could do that without to much inaccuracy. At normal probe speeds the probe
would seriously overrun the contact point and risk smashing the probe or workpiece and even if that didn't happen the
overrun would screw your accuracy.

Mach4 has four independent probe inputs, g31, g31.1, g31.2, g31.3. Mach3 has one, g31.

Craig
Title: Re: Touch plate + touch probe connection
Post by: grsabourin on February 01, 2019, 11:25:20 PM
Thank you for your really nice anwser