...but insurmountable (for now) problem with tool touch probe detection. Bollocks.

What a lark!

Hmmm. I seem to be playing a guessing game. The software guys who configured the "PLC" logic in the Centroid system knew what they wanted it to do and described it as they saw logical. However, things don't quite work out so logically if you are The Fat Bloke sitting in my workshop.

Take as an example the "probe detect" input. That's a loop back connection that pulls the "probe detect" input down to ground when the probe is plugged in. It can be used to detect if the probe is present - or more importantly if it is missing - to prevent you trying to touch off your expensive tooling against a disconnected tool touch sensor.

When the tool touch sensor / tool setter / whatever touches the tool, it pulls the "probe triggered" input down to ground. My touch sensor is pretty much like the Centroid TT-1 "mechanical" device, so I'll refer to that from now on, for simplicity.

So that's 2 inputs that need to be pulled down to ground. Given that all the 8 inputs have pull ups (to 24V), you can only attach switches between the input and ground. So should the "probe detect" input be described logically as "normally open" (NO) or "normally closed" (NC)? Depends if you think you are trying to detect the presence or absence of an external circuit. That one kept me guessing for a while....

Problem with parameters for work probing and tool setting:

Seems there is an issue with the software when you try to fit both a TT (tool setting sensor) and a touch probe (like my Renishaw). There is a "spindle lockout" function that looks at the "probe detect" input and stops spindle operation - and also inhibits probing if there isn't a probe tool fitted. However, if you get it working for the probe tool, the tool setter detection doesn't work. WTF?? 

Looks to me as if there is a logical issue that Centroid need to look into. For now almost everything works, although I will need to be careful if I use the automatic tool length measurement function, as it can't tell if I have actually plugged in the tool setter. The jog rate will also be limited due to the system somehow thinking there's a probe fitted. 

Rather than repeat everything chapter and verse, here's the post I made this afternoon on the Centroid Acorn user forum:


Hi Keith (and thanks, Fredsan)

I've spent several hours looking at this now, testing all the possible permutations and combinations of the relevant parameters. I think the situation is now fairly clear, having proved each setup to exhaustion and beyond.

The problem arises with the probe detect function, which I think explains how Fred hasn't seen an issue. If you have the tool touch probe (TT) hard wired, you don't need to do a probe detect on it. In my case, I have a pluggable TT probe, so I want to detect if it's present before sending the tool towards it(!!).

The problem seems to be that if the probe detect input is triggered by connecting the TT probe, the tool length search function doesn't work correctly - it gets confused and thinks the tool signal is active even though it isn't. The result is that the quill retracts, which isn't very helpful. It's not a matter of correctly configuring the parameters, as I have them working for the touch probe.

The solution for me (for now) is to leave the TT detect wire disconnected. That way the TT tool length probe function works correctly. The downside is that the controller doesn't know if the TT is actually plugged in and I could run the tool into my TT. The other issue is that somehow the controller believes that there is a probe permanently plugged in, so I get a "453 jogging while probe detected" whether it's plugged in or not.

The other related issue is that although my Renishaw probe functions fully with the various probing operations - and the system will only probe with it plugged in (which is very good) - the "453 jogging while probe detected" message goes away when I plug it in.

My parameters are like this:
#11: -4
#18: +6
#44: +7
#257: -6

Yes, parameters 18 and 257 are opposite polarity(!!). My probe signal is input 4, detect input 6, TT signal input 7.

I'm pretty certain there's a logical error somewhere in the software. One solution for me would be to hard wire the TT and fix it on the table but that's not ideal and it won't get rid of the "jogging while probe detected" message. Presumably that's also limiting my jog rate.

I've attached my current report if that will help.

So at least I can set up my tool lengths automatically now and the touch probe works safely. But hopefully this TT detect issue can be fixed too.

Pleased to report that everything else seems to be working nicely. Very pleased with the conversion so far!

Murray

But at least I have my touch probe working (safely!) and the automatic tool setting function works, even if I have to take care to ensure it is plugged in first....

You'd have thought (hoped?) that the spindle wouldn't work if it thinks there's a probe fitted. But it seems happy to air cut my current file. Even though it claims there is a probe fitted when I jog (there isn't).