Mach 3 changing home position

[Yasser47]

Hey everybody
I am having a very strange problem with mach3 homing
If I reff all axis and get to a certain point and set it X 0, then I reff all axis again and go to that point its perfect zero with the dial indicator,
BUT
Every time I shut off the system including the PC and rerun everything again and reff all home, even my work offset was save it always gets a deviation around 0.05 mm

recap, if the system is up i get every time the work offset zeros very precise after homing all axis, and when i shut the system off and rerun it it changes the position

I tried Omron Proximity switches and Pizzato Limit Switches , almost the same deviation for both!


Any ideas?

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[GME]

Hey everybody
I am having a very strange problem with mach3 homing
If I reff all axis and get to a certain point and set it X 0, then I reff all axis again and go to that point its perfect zero with the dial indicator,
BUT
Every time I shut off the system including the PC and rerun everything again and reff all home, even my work offset was save it always gets a deviation around 0.05 mm

recap, if the system is up i get every time the work offset zeros very precise after homing all axis, and when i shut the system off and rerun it it changes the position

I tried Omron Proximity switches and Pizzato Limit Switches , almost the same deviation for both!


Any ideas?

I don't know for sure, but given such a small amount of deviation, I'm guessing that it is produced by (1) your steppers being locked when you reference all. (2) your stepper unlocking when you shut down, and (3) your stepper relocking when you start back up again. The process of locking and unlocking and relocking is probably producing a tiny bit of of movement. I always Ref All whenever I first start the machine, so what you are experiencing has never occurred to me as a possibility.

Gary

[Yasser47]

I don't know for sure, but given such a small amount of deviation, I'm guessing that it is produced by (1) your steppers being locked when you reference all. (2) your stepper unlocking when you shut down, and (3) your stepper relocking when you start back up again. The process of locking and unlocking and relocking is probably producing a tiny bit of of movement. I always Ref All whenever I first start the machine, so what you are experiencing has never occurred to me as a possibility.

Gary

Hey Gary
I am using closed loop hybrid stepper servo motors
I do reff all home everytime i start the system again
Thats why i am asking. Its very strange.
If i reff all home and get to zero its perfect. And do ref all home again and get to zero still perfect. Shut the system and reopen and do reff all home pooof i get a diviation. And this deviation still the same after every reff all home until i shut the system and reopen then pooof again another new diviation.

[GME]

Hey Gary
I am using closed loop hybrid stepper servo motors
I do reff all home everytime i start the system again
Thats why i am asking. Its very strange.
If i reff all home and get to zero its perfect. And do ref all home again and get to zero still perfect. Shut the system and reopen and do reff all home pooof i get a diviation. And this deviation still the same after every reff all home until i shut the system and reopen then pooof again another new diviation.

I guess I didn't completely understand the sequence of events. If you shut down and restart, then Ref All, you should get perfect zero again. I thought you were Ref All, shutting down, starting up again, and without Ref All again, measuring to see if you were still at perfect zero. If I'm now reading you correctly, what's happening makes no sense to me. Ref All should go to the same place each and every time, regardless of shutting down and restarting.

As far as the misunderstanding expressed in my previous post, I doubt it would matter whether you had a traditional stepper, or a closed loop type.

Gary

[dazp1976]

Try what I do.
I G28 home at the end of every day before I switch off.
Then the next day I turn on and just hit ref all home without moving anything and good to go.