Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: BarryM on October 24, 2016, 01:35:53 PM

Title: Machine Coordinate
Post by: BarryM on October 24, 2016, 01:35:53 PM
Why can't I zero the machine coordinate displays?
Title: Re: Machine Coordinate
Post by: Davek0974 on October 24, 2016, 02:25:43 PM
How are you trying ?  :)

The only real way is to home the machine.
Title: Re: Machine Coordinate
Post by: BarryM on October 24, 2016, 03:07:55 PM
What determines  home position?
Title: Re: Machine Coordinate
Post by: Davek0974 on October 24, 2016, 03:39:29 PM
Its generally up to you, my home on the plasma table and the mill is front-left corner, seems a pretty standard location.

Its determined by the location of the homing switches and also where you tell the machine that "home" really is - the switches can be anywhere along the axes - on my plasma they are combined with the limit switches but on the mill i have limits at the end and homing switches in the middle as there was more room to fit them there, the offset distance is set by the value of "home offset" in config.

Many user don't even bother fitting switches, just tell the software to home without switches - this will just zero the DRO's wherever you want, but I couldn't work like that - if you have to restart after a quick stop or a crash you need to know exactly where home is so you can carry on easily
Title: Re: Machine Coordinate
Post by: RICH on October 24, 2016, 08:14:26 PM
Quote
What determines  home position?

The CNC Controller is a software Program called Mach 3 and provides for controlling all the movements and associated commands. The CNC controller (Mach) does not know a "practical" Machine Reference Point to work from, thus, the controllers “0,0,0” is somewhat meaningless and has unlimited movement capability.  When the controller is turned on it monitors axis movement starting from Mach's  “0,0,0” value for each axis and displays the absolute movement using Machine Coordinates.

Machine Zero is a fixed point within the physical machine travel limits and does not normally change. It is typically called Machine Reference point, machine zero, or simply "Home" Position.  Machine zero can be located / defined anywhere by the user. Usually it is located to provide for full available machine travel usage.

Now knowing the above ......How do "YOU" want to tell the controller where home is?

RICH