Prox switch issue - frustrated

[denmanmarine]

Hi all,

I have read through the forum re prox switch issues. I have a new PRS Alpha 120-60 and started cutting last week. When we were doing the initial "air cuts" with no dust extraction on or spindle on, the machine would stop and we would get a "hit proximity switch" warning and then we would resume. We were at least a foot away from the prox switches at the time. It was an intermittent problem with no location occurring twice.

I updated the software to 3.8.8 yesterday and cut a couple of small pieces ok. Tonight I was cutting some more and was nearly finished the job when the machine said I hit a stop (around 18 inches away from a stop). I pressed resume and fired it up and the spindle lowered into the material then proceeded to cut diagonally across the 16mm piece at full depth (not following the file) snapping the 1/4" cutter in the process. I hit space to stop, then resumed with an air cut and it cut the rest of the file without issue and returned to home. Interestingly, the piece where the bit was snapped was only partially cut through (it had completed one pass) and had cut just fine on the first pass.

This is frustrating. The switches are set up correctly and I have re-checked all wiring. I can obviously turn them off but I don't want to.

If it means hitting resume every now and then I could live with that (except it is a new machine and shouldn't do this) but I am now concerned that if I hit resume the spindle will go random again and wreck the piece rather than following the file.

Being new to this, I am not sure if I am doing something wrong on the resume?? I don't want to have to start the file again from scratch every time I "hit" a stop.

regards,

Andrew

[denmanmarine]

Just to add to this post, I just ran the same file again and had 1 prox switch issue in a different location. When I resumed, the machine only moved at a crawl for around a minute then continued at normal cutting speed. The bot then appeared to move to a different location in the cut file than it should have but then continued and completed the run.

Something not quite right after the resume is hit...

Andrew

[jerry_stanek]

check the wires for your prox switches one could be broken.

[denmanmarine]

Will do Jerry.

Any real downside to just turning them off? It seems a few people have issues?

Andrew

[denmanmarine]

I was just reading the thread on 3.8.8 issues and it reminded to advise what PC is being used.

I'm running a core I5 laptop, with 6GB RAM, Win 7, and all power saving stuff switched off, hooked into mains power.

Andrew

[Brian Harnett]

Make sure everything is grounded and if running dust collection a ground wire in the pipe.

[adrianm]

Sounds more like a wiring fault or grounding issue than anything to do with the PC or software to me.

Have you talked it through with Shopbot support?

[denmanmarine]

Hi Adrian,

I just sent them off a support request but also wanted to try the forum as there is a good deal of experience here.

I just want to get cutting as I have a lot of work piled up to get through (and it is fun to use as well!).

Andrew

[jerry_stanek]

If you have an old desktop try that you don't need a high end computer to run it

[coryatjohn]

It may be a grounding issue. Be sure that EVERY moving part has a ground wire. Be sure the ground is actually grounded too. Also, be sure your spindle cable is physically separated from the other cables.

Double check your connections inside the control box as well. There might be an intermittent fault in that area. The connectors are kind of difficult to get right for the prox and other switches.

[bleeth]

When you ground the unit you need to make sure your connections are "linear" and not creating a loop. That will defeat the purpose. We are speaking of grounding the machine here and not hooking up the grounds when you wire the control box.

90% of the time the issue that you are describing comes from loose/nicked wire or grounding problems.

On the control box end: Those tiny wires going into the wire connectors at the control box can often be the problem even though you don't think so. Particularly the grounding ones where you often have to tie a few together.

[denmanmarine]

Thanks for the replies guys. As usual Shopbot support are very quick with their replies too. I'll troubleshoot today and report back tonight.

Andrew

[denmanmarine]

Well machine was all grounded today and I got all excited when I air cut 5 files with only one "limit switch hit" error. Still working on this but it is an improvement.

Since SB recommend you ground the machine as per the wiki, they really should include a grounding kit with the machine and instructions to do so when you are initially setting the machine up.

regards,

Andrew