What do you mean by,
"this triggers a (soft) limit switch"
Is it a real switch that you have set up in some way so as to be an addition to the hard limit switches or are you meaning you get a message saying that you have exceeded the soft limits?

Is your tool change position right on the soft limits? If so then could be servo overshoot just taking it past them slightly.

Hood

No, this is an internal limit of some sort, not a physical switch at all and not mach soft-limits as i dont think you get a message on screen when they trip.

It seems to be a CS_LABS thing - if the g-code tells it to go somewhere it knows it cant I get a message on screen - "Limit switch triggered"

This has only ever happened on the CSMIO machine, never on the plasma or mini-mill.

It's like something is getting confused, especially if not only ever when tool-length offsets are in play.

Seems to be the G28 G91 Z0. line that sometimes triggers it but only after the first tool has been run???
It uses that line at the end of each tool to send the Z right up to machine home.
Maybe i need to get the post edited to use G0 G53 Z0 instead?

Its a bit complicated to note exactly what and when it happens.

Ok well could it possibly actually be a limit switch has been seen? Could be vibration or noise and the switch is seen for a very short period by the IP-A and thus the message as I think that is the only time you would get such a message.
Might be worthwhile setting a small amount of fitering in the IP-A plugin and see if it helps. You will find it on the Misc IO page, it is defaulted at 1 (4ms), might be ok if you set it to 2 or so if it is just occasional.
Hood

Ok, will try that but there is no message when jogging into a soft-limit zone?

It can't be a physical limit as they are all wired to the safety circuit first so any false triggering there will throw the safety relay out first killing the power, the only other switches are physical homing ones, they are all industrial stuff, roller levers, with very large travels so a false trigger would not happen there as well as the fact that they are all mounted well away from the actual physical travel limits and i use a home-offset.

It was random as such that it does not always do it but then repeatable as in it was always after the first tool-change and always when it sent the Z to home.

Not sure what you  mean by
"Ok, will try that but there is no message when jogging into a soft-limit zone?"

If you have softlimits set up with the IP-A and jog to them the axis will stop dead at the soft limit and you will only be able to jog the opposite way, no message though and no slow zone like other controllers have as the IP-A knows exactly where the axis is and can stop it at the defined accel in motor tuning and it is spot on.

What you said above was the message mentioned Limits, not Soft Limits, and that is the reason I think it is a Limit signal that is being seen.

How have you got the limits set up? You say they are wired to the safety relay but do you have an input from the safety relay going to the IP-A that is set up as a Limit ?

Only time I have ever seen the IP-A give a limit message is when I hit a limit, ie when softlimits are disabled and it actually hits a limit  and the only time I ever have the soft limits disabled is when I initially set up new machine. I do that so  that I can find the positions of the limits in Machine coords for setting up the soft limits.

So I still think it is likely to be an issue with the limit input to the IP-A and for some reason it is seeing a signal momentarily.

Hood

The limits are wired to the input side of the Telemechanique safety relay, the two output channels are connected to the supply contactors and an input on the CSMIO.

The input to the CSMIO is set up as the e-stop input.

Yes the message is in the message line on screen and says "Limit switch triggered" - it will do this even before moving an axis if it thinks it needs to move somewhere it knows it cannot, at least thats the way it seems.

This is code related in that it never does it when i'm just jogging manually or with the jog-wheel, and only ever seems to do it after the first tool change.

Maybe it is related to the screen-set, this is the 2010 one.

Might be the screenset but can't really see how it could be, worth a try I suppose. As said only time I have ever seen a limit switch message the same as above is when I have actually hit a limit switch.

Hood

Yep its an odd one.

As soon as i have the new motor fitted, i intend to repeat air-cut the same code as before and see what happens.

Something that rarely gets mentioned but was brought up by my motor change...Power required...

I now have a 3ph 2.2kW spindle motor on a 230v vfd, 700w X AC servo, 700w Y AC servo, 400w Z AC servo, maybe 100w for pc and controller on this machine.

How do i calculate the supply capacity allowing for diversity - it will not be running 100% flat out all the time, far from it

I know i need to uprate the MCB's and supply cables as the build was originally for the small 1.5hp spindle motor and I only fitted a 10A mob for the spindle.

Adding up the maximum ratings for all drives gives a figure way more than i can supply because of no diversity allowance

Any thoughts?

I would suggest you size  to comply with  the National Electric Code and local code.
Amp draw can be measured if you have a snap around ammeter.

Ask a licensed electrician or electrical designer as they can tell you quickly all that you need to know
and save you the time of trying to interpret / read the code.   

RICH