Mach3 What did I do wrong?

[murphmoose]

I'm a brand new tormach owner and loving the machine so far, but I just noticed something and wondering if I pushed something wrong.

After referencing the xyz axis, all the lights next to the axis in mach 3 turn green. When I exit mach3 and turn off the machine and come to it the next day, the lights that were green that showed that it was referenced are now red.

Is this correct?

Thanks,
Steve

[cheetahcnc]

Normal. Always reference all axis after turning on the machine. Many also reference after an e-stop, or other anomaly.

Jim

[tbaker2500]

Since so much can change with the machine off, it assumes that if anything has been shut off, that it has lost track of the absolute position of the axis. There are limit switched on the axis, and when you Ref All, it moves until it hits the limits. It now knows exactly where there table is. This is really useful if you want to define the zero of a part, and have it remember it the next day. When exiting Mach3, it will ask "Save Fixtures?" If you say yes, it will save the position of zeros you set. Read up in the manual about fixturing to learn more.

[Jeff E.]

I keep hearing about "ref all" being some kind of magical action that must be used to before using the machine. In theory by doing this you should be able to return to some 0,0 location if you have a failure or shut down. In reality this does not work given the state of current limit switches installed on the machine.
They do not have the repeat-ability to return your machine to its previous ref'd position. Unless you can tolerate a few thousands error you are likely wasting your time doing ref all.

(This switch repeat-ability issue has been confirmed by Tormach via phone conversations)

You probably will be better off having a fixed ref point on your table or fixture if you want to return to known point.

Just My 2 cents,

Jeff

[zephyr9900]

Jeff, the main functional consequence of not referencing the machine, is that Mach will not work in machine coordinates (e.g. M998 toolchange position, which is defined in machine coordinates). Frankly, that is the only reason I ref my machine. With my full enclosure, I need to raise the head to a repeatable position for toolchanges or the door will hit the enclosure. (Yes, Don, a power drawbar would fix that! )

Randy

[tbaker2500]

I've found in practice that the limit switches are good to at worst 2thou, and typically 1 thou. Considering the overall accuracy of the machine, it's pretty darn good. TTS is only guaranteed to be 1 thou repeatability.

[zephyr9900]

And Flick's neat "double-touch" homing macro described in this thread maximizes the performance of repeatable homing with the stock switches.

Randy

[Scott_M]

And Flick's neat "double-touch" homing macro described in this thread maximizes the performance of repeatable homing with the stock switches.

Randy

Thanks for finding that Randy ! I am glad I didn't have to look for it ! But boy does it work well. My repeatability is still a few tenths using that method.

Scott

[Don Clement]

With my full enclosure, I need to raise the head to a repeatable position for toolchanges or the door will hit the enclosure. (Yes, Don, a power drawbar would fix that! )

Randy

Yep! BTW I hardly ever open the door any more between the spindle upgrade and the PDB.

Don

“Home, home again
I like to be here when I can
When I come home cold and tired
It's good to warm my bones beside the fire
Far away across the field
The tolling of the iron bell
Calls the faithful to their knees
To hear the softly spoken magic spells”

[sperman]

Normal. Always reference all axis after turning on the machine. Many also reference after an e-stop, or other anomaly.

Jim

My machine loses counts if I have to use the e-stop. I guess that is normal behavior.

[mike sr1]

My machine loses counts if I have to use the e-stop. I guess that is normal behavior.

My Z will drop .020 to .040 iif the E stop is used, the reading in Mach will remain the same.
I called Tormach about it and they said it is a function of the power going off to the system causes this. Their work around is to use the esc key or the space bar to shut off the machine.

This is what I have been doing and it works fine instead of using the E stop.

[philbur]

I don't think it is a work around, it's the way it has to be. A work around suggests things are not behaving correctly, even Tormach have to live with the fundamental laws of the universe. If you hit the Estop it immediately cuts all power (after all it is an Emergency Stop). However if things are in motion (or under load) they will continue in motion until the drag resisting that motion brings it to a standstill. Even the Z axis brake requires a finite amount of time to react. So, if you use Estop and don't re-reference the machine before you continue, you will only have yourself to blame if things turn out badly.

I suppose you could put in a set of timers that performed the Estop shutdown in a logical sequence, but then it wouldn't be an Estop. Estop is for use in an emergency not for normal operation.

Phil

My Z will drop .020 to .040 iif the E stop is used, the reading in Mach will remain the same.
I called Tormach about it and they said it is a function of the power going off to the system causes this. Their work around is to use the esc key or the space bar to shut off the machine.

This is what I have been doing and it works fine instead of using the E stop.