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Author Topic: Soft limits info please...  (Read 6267 times)

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Offline Davek0974

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Re: Soft limits info please...
« Reply #10 on: February 17, 2014, 08:13:27 AM »
Ok thanks

I will not downgrade until i hear back from you as i really don't like downgrading stuff, it always seems to cause problems.

If there is a better way of doing things then  would rather get it right now before it starts costing me metal wastage etc.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Davek0974

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Re: Soft limits info please...
« Reply #11 on: February 17, 2014, 08:49:17 AM »
I posted the same issue on Sheetcam forum and got this reply....

"I think the soft limit warning is due to the probing move. During simulation Mach does not know when the probing move will end so it uses the maximum possible move. Each time it probes it moves further down, eventually running into your soft limit.

There isn't really any good solution to this apart from turning off soft limits or disabling probing."

SO second question, is there a way to have the Z axis return to machine zero at the end of a run???
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Davek0974

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Re: Soft limits info please...
« Reply #12 on: February 17, 2014, 09:15:29 AM »
Just noticed the error is on Z-Max which is the upper zero point so the code is sending the head above zero and not too far below.

Apart from disabling Z soft limits, is there a way round this?

All I want to do is have the machine probe Z height before every cut starts, sounds simple but seems not.

I really like the soft limits but if i have to kill the Z one then so be it i guess.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline stirling

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Re: Soft limits info please...
« Reply #13 on: February 17, 2014, 09:28:16 AM »
An alternative way of looking at this is to ask why you're using soft limits at all. On a small light machine they really don't bring much to the party. If you DO want them for some reason then they're perhaps most useful to prevent jogging into a limit but personally I'd just turn the bloody things off (at least) when you're running code. Why would you reduce the size of an already small work area for no particular gain?

Offline Davek0974

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Re: Soft limits info please...
« Reply #14 on: February 17, 2014, 09:33:49 AM »
I like being able to run the gantry around without slamming it into a stop, I guess the z limit is the least important so i could kill it i guess.

Its most useful while im still testing the machine i suppose.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline stirling

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Re: Soft limits info please...
« Reply #15 on: February 17, 2014, 09:47:09 AM »
Fair enough. I just never really see the point of limits on a small stepper machine - never mind soft limits - but that's just me.

Thing is that if you hit a soft or hard limit when you're running you more than likely just screwed the job - so the best approach is not to do it. Plus limits of either kind in plasma do nothing to stop the machine when you get a tip-up and that's FAR more likely AND far more likely to cause damage.

Offline Davek0974

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Re: Soft limits info please...
« Reply #16 on: February 17, 2014, 09:56:21 AM »
That's a pretty good point there Stirling, thanks.

I'll kill the Z soft limit at least for now.

My main goal is to protect the machine not the workpiece at present, this is hobby stuff and i've spent a fair bit on it so just want to protect my build that's all.

Dave
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.

Offline Davek0974

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Re: Soft limits info please...
« Reply #17 on: February 17, 2014, 12:53:45 PM »
Ok here's what I've done...

I have disabled the soft limits on the z axis, this makes the code run very nicely.

Secondly, I have modified the probe switch so that it now has two break contacts, one opens for the probe sense and further travel opens the second contact as a limit switch.

Now, when probing it works as normal, but during manual  z axis movement if I ram the torch into the table the second switch acts as a normal limit switch. Works pretty sweetly too ;)

At least I know that it is the way the probing is initiated that was causing the issue now.

Thanks for the help on this one.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.