Milltronics VM16 not homing.

[Ciaran]

Hi All,
I just bought a Milltronics Vm 16. Its 1997 and did appear to be working fine when it cut out and turned itself off.Could have been me messing with the unfamiliar controller but now here is my problem.
When I turn it on and reset the servos and go to home the machine the z axis drops instead of lifting trying to find its home position.
Has anyone any idea why the machine would do this.It was homing fine yesterday and I have not been messing with the parameters.
Any help would be greatly appreciated.
Regards,
Ciaran.

[moldcore]

Have you checked the limit switches for chips?

[Ciaran]

Hi,
What do you mean "for chips"
Cheers Ciaran

[mholden]

If the head is moving down the home switch maybe stuck in. you can see this on the diag screen hit display diag then z for the z axis on the left side look for home switch it should be a zero until the switch is depressed. if it is a 1 all the time the switch is stuck in.

[MazakMikeO]

I assume the Z axis is not near the limit switch, sometimes you need to "back off" the axis before it will home in. And look for chips means see if there is any "swarf" or metal cuttings there.

[Ciaran]

thanks I will check in the morning.9.45pm here now.Thanks for the advice

[Ciaran]

Pulled out that limit switch and it appears to be fine.In the diag page it is showing as 0.
I traced the wires to the back and put a meter on them and as we work the home limit switch it is working fine.The strange thing I noticed is that if I push the emergency stop the 0 changes to 1 and then when I reset the servos it stays at 1.Could this be a software problem?The home limit for the other axis is not changing to 1 when the emergency stop is pushed.
Any other ideas please.
Regards Ciaran.

[Ben Colby]

Ciaran Kennedy?
Father of Tadgh

[Ciaran]

Afraid not different Ciaran from Wicklow Ireland

[T-nuts]

Sounds like the switch is stuck. If the machine makes its limit it then backs off the switch, to find home. If the switch is stuck down the head will keep going all the way into the table if you let it. Work the switch slowly with your finger and see if it feels sticky.

[Farmers Machine]

Mine does the same thing about 3 out of 10 times on start up. To home out the control sends the head to the limit switch. from there it backs away and then goes very slow until it finds the encoder marker. If the Z axis belt has ever been replaced you are enough teeth out of time so that at fast feed to home the encoder marker is not in the right place when the head hits the switch. when you over shoot the home switch the overtravel switch will stop every thing and E stop the machine. call milltronics to get the repair man's code to get into the set up parameters. there you can home the machine with your finger on the reset button and hand wheel down to get off of the limit switch, then start your homing process again. NEVER NEVER NEVER EVER operate the machine from the home here location!!! it is just for emergency recovery. about once a month I have to spray penetrating oil on the limit switch buttons and work them with my finger several times to free them from sticky stuff that is left over from dried coolant, and then every thing is back to normal. Good luck the Farmer.

[jpawelk]

To enable a home here complete the following:
1) Power on the machine and take it out of emergency stop
2) Press the F7 (PARMS) button
3) Press the F1 (SETUP) and then the F1 (LEVEL) buttons
4) The control prompts you for a validation code, type PROTO3 and then press enter.
5) It then prompts for an access code which is 3.
6) Escape to the main menu of the control and press F1 (HOME)
7) The F10 button should now show (HERE), press it to highlight it
8) Press CYCLE START.
This will home the machine in its current axis locations. Move the axis to your desired position and then home normally.