Setting up Probe Basic on my machine questions and issues

when in doubt, it help to read the instructions which tell you to delete those comments

 

Fair enough. I thought I had gone through all the steps but I guess I missed it.

I just got a touch probe and want to set it up alongside my tool height setter.

Turns out the tool height setter I bought years ago is NC.
Without even thinking about checking I bought a NO probe which if I am thinking about it correctly if I wanted to wire them into the same pin it would have to be NO.

From what I can tell in reading though it seems like I should be able to wire them into separate pins on my 7i76e, distinguish one as NO, the other as NC, and get it to function properly correct?

And from reading it does sound like LinuxCNC still only has one probe function right? So in the configs I tie both sensors/pins to the single probe function correct?

There is a way to do it in Hal, run a search on the forum for an example. I don't have one handy to share,. But it was xor component used I think from memory. Or maybe someone has something setup they can share.

I found a couple posts earlier that were talking about using basically an or argument. Looking like this must be kind of what they were talking about.

My understanding being that this allows you to use one or the other which solves most issues.
It is weird because I was reading about using a touch probe and tool setter together as a way to do tool offsets and or just to zero the probe and I would have been sure I read that here or other linuxcnc group but maybe not.

So in a quick search it looks like XOR can be used to deal with one sensor being NO and the other being NC, but they are still only tying to the one probe function right?

I read a post where you Lcvett talked about setting offset on a cutter, facing a surface, then calibrating your probe off that surface. Which solves the one use case I can imagine for wanting to use both but it seems like a pretty janky solution.
I can see having two probes with two moving elements adds some complexity and probably some stack up. Is this just considered an unacceptable solution to calibrate Z on a probe? Or is it just that no one has bothered to implement a useful feature because it's not a priority?

the methodology of using a measured cutter verse probing the tool setter pad with the probe is to avoid probing a moving object which can cause a misread of the actual touch probes trigger height. because no two probes will have the same exact spring rate to trigger the chance of inconsistency or a false touch probe tool length offset is much higher then if probing a solid object. granted this variance would be very small so depending on what kind of machine results tolerance you are hoping to achieve it may be within your use case.

the XOR component would allow for using the touch probe to touch off on the tool setter, it is simply using the component to gate the two discrete probe trigger signals into linuxcnc's single probe input. there are some considerations. if the touch probe is NC and is not mounted connected to the machine full time, ie.. it is plugged in or removed depending on if it is being used or not. this causes a bit of strife as the open signal when it is removed puts the probe input in a triggered state. so if this is the scenario you are using you will need to use a dummy plug to simulate the probes closed circuit at the jack. I have seen some jacks that have the ability to close upon removal of the male plug, they are used for power/charging jacks to divert the power circuit back to the battery when the plug is removed. I think I added a diagram some time ago for this in a post but when/where escapes me.

if the tool setter and touch probe both use a normally closed circuit the single input can be run in series so long as if one is removed the circuit is closed artificially.

XOR can also be used in that scenario, just depends on how you want to configure the system. there should be a stock component specifically for probing to make it easy or a prewritten hal example somewhere in the docs as this question comes up far too often not too.. if you guys come up with a working hal example or examples, we can sticky it here for PB users or other general searches to help folks get it sorted out easily.

Thanks
Haven't gotten back to the touch probe stuff but hope to soon.

Currently a couple other issues. The first is definitely PB related.
Every time I start PB it puts the coordinate readout in inches when linear units is set to mm in the ini.
G21 does switch it but it's still annoying. How do I set it so everything starts and always stays in mm?


The second I don't remember if this was an issue in other UIs but if I hit home x or y it does not lift Z before homing.
I see there is a go to home file in subroutines which I assume is used for home all but don't see anything specifically for individual axis. Would I need to create a subroutine for x and for y to get it to Z0 before homing them?