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### Author Topic: Machine coordinates by start from mach3 (mill) always at zero?  (Read 6327 times)

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#### Burgy

• 4
##### Machine coordinates by start from mach3 (mill) always at zero?
« on: December 29, 2015, 06:07:07 AM »
Hello,

When i start Mach3 (milling) my machine coordinates are always shown as zero, it does not matter where my spindle is the DRO shows the maschine coordinates as zero, what am i doing wrong?

regards,
Burgy
« Last Edit: December 29, 2015, 06:09:22 AM by Burgy »

#### BR549

• 6,952
##### Re: Machine coordinates by start from mach3 (mill) always at zero?
« Reply #1 on: December 29, 2015, 12:27:21 PM »
When Mach3 starts up it has NO idea where in 3d space it is at UNLESS you tell it otherwise it ASSUMES it is at Zero.

And for the most part it does not matter as you do not work from Machine coords you work from Work Coords . They are 2 total different things not to be confused with one another.

(;-) TP

#### Burgy

• 4
##### Re: Machine coordinates by start from mach3 (mill) always at zero?
« Reply #2 on: December 29, 2015, 02:59:39 PM »
Hi,
Then the spindle must be Parked before shutting down, would that solve my problem ?
Regards,
Burgy

#### BR549

• 6,952
##### Re: Machine coordinates by start from mach3 (mill) always at zero?
« Reply #3 on: December 29, 2015, 08:04:09 PM »
Only if you park it where you want zero to be.  OR you can reference the machine home and tell it where it is.

(;-) TP

#### Burgy

• 4
##### Re: Machine coordinates by start from mach3 (mill) always at zero?
« Reply #4 on: December 30, 2015, 02:29:50 AM »
Referencing the machine cannot work as it has no end switches, parking at zero should solve the problem.
Will G28 bring the spindle to machine zero or is there a better way?

Regards,
Burgy

#### RICH

• 7,419
##### Re: Machine coordinates by start from mach3 (mill) always at zero?
« Reply #5 on: December 30, 2015, 07:01:07 AM »
Burgy,

You need to understand some basics.

When Mach3 starts up it has NO idea where in 3d space it is at UNLESS you tell it otherwise
it ASSUMES it is at Zero.

Mach keeps track of axis movement from the moment it starts up using machine coordinates (MC).
As Terry said, Mach ( the controller ) assumes zero values for MC's. The controller is blind, and can't see the actual machine physical location of MC's=0 on startup. It also can't read the operators mind on where they want zero to be. The user must define the physical location to the controller.

Thus the user either accepts the start up location or defines a MC=0 location to the controller.
When the operator moves to some desired location on the machine where they want MC's=0 to be they tell the controller where that spot is. When the controller is informed of the physical location the operator
wants it is said that the machine has been referenced. The controller started with an arbitary MC=0
and when an actual loctaion is defined the machine is said to be referenced / homed.

To help the controller see and know where the axis locations are physicaly located the user switches
can be used to automate the above on start up.

Note that Work Coordinates( WC )are not MC's. WC is associated with the physical location of the part
as related to Home.

Specific Gcodes can be use to return to home or MC's.IE; G53 is used to move in Machine coordinates.

Read the Mach Manual...............

RICH

#### BR549

• 6,952
##### Re: Machine coordinates by start from mach3 (mill) always at zero?
« Reply #6 on: December 30, 2015, 09:27:57 PM »
G28 sends the machine to the Point that you defined in setup, G30 will send it to the Machine home position

(;-) TP

#### Burgy

• 4
##### Re: Machine coordinates by start from mach3 (mill) always at zero?
« Reply #7 on: December 31, 2015, 10:31:43 AM »
Thank you all for your help, now i have some testing to do.

Best regards,
Burgy