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Author Topic: Mach 4 homing  (Read 646 times)

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Offline Laz

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Mach 4 homing
« on: March 28, 2020, 07:04:49 PM »
Hi.
I'm fairly new to this an would like to ask anyone who could help me .

I'm currently building my second CNC Router and this one has dual lead screw and stepper motor on my X axis
Set up motor0 as master and motor3 as slave to motor one
Also have homing switches on all axis

Everything is working fine when i jog the axis both motor0 and motor3 are turning and the gantry is working fine
The problem is when i try to home the machine . Motor0 on the axis will move but motor3 won't and the gantry will move out of square and to prevent damage have to stop the machine

How can I get both motors to move together

Thanks
 
Re: Mach 4 homing
« Reply #1 on: March 28, 2020, 09:03:40 PM »
Hi,
I think there may be some confusion on the Homing/Soft Limits page.

You have nominated the X axis (axis 0) and A axis (axis 3) to home together AFTER the Z axis.
That is to say that both axes are number 2 in the homing order.

Your motor assignments page shows that you don't have an A axis (axis 3). You do have a motor 3, it is
slaved to motor 0 and BOTH are assigned to the X axis (axis 0).

May I suggest reset the homing order  of the A axis (on the Homing/Soft Limits page) from its current '2' to '0',
ie the A axis is not to be homed.

Try it and see.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach 4 homing
« Reply #2 on: March 28, 2020, 09:11:26 PM »
You stated that you have Motor 3 set up as a Slave to motor 1, but your config screen shows it as slaved to motor 0, which I assume is correct. You also have Homing configured for the A axis which has no motor assigned.

Do you have the input signal for Motor 3 Home configured?
Steve Stallings
www.PMDX.com
For PMDX product support, please use PMDX forum or direct email for quickest response. We do not use this forum as our primary product support site.
Re: Mach 4 homing
« Reply #3 on: March 28, 2020, 09:22:45 PM »
Hi,

Quote
Also have homing switches on all axis

How exactly do you mean?.

On the master/slave axis do you have a home switch for each motor OR do you have one switch for both?

It makes a difference. When a motor is homed it will drive to its home switch, whether it be a master or slave.
If a motor does not have a home switch assigned to it, it won't move and will just 'home in place'
Could it be this is what is happening? Does the slave motor (motor 3) have a home switch assigned?

There are two reasonable solutions to this. You could have two separate switches at each end of the gantry.
In this case you would have two inputs, one being the home switch for motor 0 and the other being the home switch for
motor 3.

The other way is just to have one home switch on the gantry and both motors share it. I have attached a pic of
how that would look on the Control/Input Signals page. Note that both motor 0 home AND motor 3 home are enabled
but they point to the one input pin, port2 pin10 in my example. That is so say that both are enabled but they monitor
just the one switch.

Clear as mud?

Craig
« Last Edit: March 28, 2020, 09:24:20 PM by joeaverage »
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Offline Laz

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Re: Mach 4 homing
« Reply #4 on: March 29, 2020, 01:17:24 AM »
Hi.
Have a honing switch for separately for A and X axis on two different inputs so it should square the gantry on honing but axis A just won't move
Both active low so if there is a problem with the wires it should activate and would see it
Thank you guys for quick reply.
I will double check the switches
Re: Mach 4 homing
« Reply #5 on: March 29, 2020, 01:46:16 AM »
Mach3 and Mach4 are fundamentally different in how they treat the relationship of Axes to Motors.

In Mach3 axes each have can have only one motor and when two motors are needed for one axis, you can slave one axis to another in software. This results in a "phantom" axis that are not actually commanded in G code.

In Mach4 motors are a separate concept from axes. The relationship between axes and motors is defined by Mapping. One axis can have multiple motors. Home and limit switches are associated to motors, not axes.

This can be a bit confusing, but is more flexible.
Steve Stallings
www.PMDX.com
For PMDX product support, please use PMDX forum or direct email for quickest response. We do not use this forum as our primary product support site.
Re: Mach 4 homing
« Reply #6 on: March 29, 2020, 02:00:55 AM »
Hi,

Quote
This can be a bit confusing, but is more flexible

Confusing, well perhaps the first time you encounter it but thereafter you see its a QUANTUM leap ahead of
Mach3.....and you haven't even seen the good stuff yet, the mapping and un-mapping on the fly, under program control....
your'e in for treat!!!

Craig
My wife left with my best friend...
     and I miss him!

Offline Laz

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Re: Mach 4 homing
« Reply #7 on: March 29, 2020, 03:18:23 PM »
My limit / homing switches are working fine
I'm really puzzled and it is driving me nuts
motor 3 on A axis just won't home
 
Re: Mach 4 homing
« Reply #8 on: March 29, 2020, 03:29:37 PM »
Hi,
YOU DO NOT HAVE AN A AXIS!!!

The A axis (axis 3) should have no motor/motors assigned to it.

Steve and I have said the same thing, you have an X axis (axis 0) with two motors motor0 (master)
and motor3 (slave).

You are still thinking Mach3 where a slaved axis was axis A.....thats not the case with Mach4.

Note....axes are numbered axis0 through axis6 for the six axes X,Y,Z,A,B,C.
Motors are numbered motor0 through motor31....yes that's right, you may have up to 32motors in Mach4,
and you can have as many as SIX motors on one axis, the master and up to five slaves.

Craig
« Last Edit: March 29, 2020, 03:40:03 PM by joeaverage »
My wife left with my best friend...
     and I miss him!
Re: Mach 4 homing
« Reply #9 on: March 29, 2020, 03:38:52 PM »
Hi,
secondly you have not assigned home switch inputs correctly, they should not be
Input1, Iinput2 etc they should as I indicated earlier be Motor0Home, Motor1Home etc.

If you scan down the list of InputSignals you will find the block of MotorHomennn's underneath
Input63.

I notice also that you must be using an XHC controller, its not clear to me that the XHC plugin can
accommodate a slaved axis. The plugin is that buggy that to my knowledge you are the only one using it.

Craig
My wife left with my best friend...
     and I miss him!