Found that alarm is only supressed in JOG or HANDWHEEL modes. Which is logical as you still want it to raise the alarm in a cycle...
Unfortunately this means that if you wind/jog around and end up on the software limit then switch back to MEM or MDI the alarm pops up, meaning you have to flick back to JOG, move the offending axis, 'reset' etc.
The only advantage I can see of inhibiting the alarm is when I am clambering around inside the machine using the remote handwheel to set datums or check tool reach/clearance. If I move the Z-axis in to its limit I now no longer have to climb back out to 'reset' and regain handwheel function in Z.
Inhibiting alarm in JOG mode may not always be desirable. Sometimes, before executing a program, I verify if the tool reaches the programmed extreme Z-position, by manually moving the tool to this position.
I would find it odd if the machine just stops for no reason, with the alarm I know why, press reset button then carry on... On the older controls without absolute encoders you run into over travel on the limit switches and it is annoying to get it out, but that hardly ever happens, especially on lathes.
Fanuc 0M-C... Yes that is a pain, would be nice if you could just go the other way and self clear the alarm. Now on my Lathe (Hyundai HIT-18S with Siemens 840C) if I go too far in X plus I get a SW limit alarm and can just move X minus and all is well, I still need to push alarm cancel to clear the screen but it does not stop movement like a Fanuc. Z plus is another story if I over travel in Z plus I get an Alarm " Z axis contour monitoring" which stops all axis' and the only way I have been able to clear this error is main power off and reboot. Now that's a real PITA.
I have to agree with Jrobson that it would be weird if you were moving the machine axis and it just stopped with no alarm. It leaves the question of what happened. I also agree with Dave that why would Fanuc fix something that is not broken. I have most of my experience with Fanuc but any other controls I have dabbled with have the same soft overtravel alarm when the axis has hit the predetermined distance.
I agree that it can be a PITA if the alarm occurs while in the machine with a MPG but if you overtravled Z+ you should be able to move the Z minus direction without having to get out of the machine and clear the alarm.
I understand the question as to why would some machines alarm and not others but am a bit confused as to what the problem is. When setting up machine tools there is going to be a hard overtravel switch that will throw an alarm. I usually set the soft overtravel limits just inside these switches about 1-2mm as Dave has stated. This is the complete work envelope of the machine. So why would you be jogging or want to move the machine any further then that distance?? The only time I see anyone pushing the envelopes of these alarms is if you are machining parts maxed out to these limits. It that is the case then it is just going to be a standard that comes with running that particular job.
One reason I see that having the soft overtravel settings instead of the machine just stopping at X0 as example would be because X0 has to be set somehow, probably via parameter. What if someone were to set X0 to 41” when the stroke of the machine is only 40”. The machine will not stop until it reaches X0.
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Limit Switch Alarm Option
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