Homing each side of ganty indepentently

[nova24]

I have a ball screw on each side of my gantry and I drive the nut for each ball screw with its own stepper.

How can I home each motor independently?

I would like to do what TomKerekes had mentioned a while back in this post.

"You can home the two sides independently. Mach3 via the Plugin sends a message to KFlop to home the axis. It is up to you to write a small program to perform the operation. This is a very flexible approach but does require you to write a program (or modify an existing one). A common technique is to home both axes simultaneously but stop each axis independently on separate home switches."

This is how my steppers are hooked up:

Left X-axis motor: channel 0 (pins 15 and 16 on JP7)
Y-axis motor: channel 1 (pins 17 and 18 on JP7)
Z-axis motor: channel 2 (pins 19 and 20on JP7)
Right X-axis motor: channel 3 (pins 21 and 22 on JP7)

The right x-axis motor is slaved to the left x-axis motor in the KMotion configuration.

If someone could share their homing program with some suggestions on how to address the Right x-axis motor, I could probably take it from there.

Thanks!

Dennis

[TomKerekes]

Hi Dennis,

The normal way to home slaved axes is to:

#1 not have them slaved
#2 Jog both axes at the same time toward the switches
#3 use a loop watching both switches, if a switch is detected tell the respective axis to start stopping
#4 exit the loop when both have been told to stop
#5 wait for both to actually come to a stop
#6 move both back inside the switches (possibly different amounts to adjust the squaring)
#7 wait till finished moving
#8 Zero
#9 Slave the axes together

I've attached an example (cnczone didn't like the .c extension so it is .txt) see the function called SquareX. The main routine calls it twice first with a high speed then with a lower speed.

Hope this helps

[nova24]

Thanks Tom, this is exactly what I was looking for!

But,I do have an issue getting any homing routing to work with Mach3.

I've integrated the code from what you supplied into the HomeMach3.c sample file.

I copied the code to the Y and Z axis sections and modified to work with these axes. I figured I'd start simple with a single stepper axis and get everything working before moving on to the dual stepper x-axis.

I can run the homing routines for the Y and Z axes using KMotion, but when I try to run from Mach3 by hitting the Ref All Home button, nothing happens.

I've configured the plugin to use the HomeMach3.c and you can see from the screen shot that the Thread and Variable Flags are correct.

Any ideas?

Thanks,
Dennis

[TomKerekes]

Hi Dennis,

Everything looks right to me. Is there a printout on the KMotion Console when you REF ALL HOME?

Regards

[nova24]

No

[TomKerekes]

Is Mach3 in EStop?

What VB code is in the REF ALL HOME button?

What about the REF Z button on the Diagnostics Screen?

[nova24]

Tom,

Is Mach3 in EStop?
No

What VB code is in the REF ALL HOME button?

DoButton( 24 )
DoButton( 23 )
DoButton( 22 )
DoButton( 25 )

DoOEMButton(133)
DoOEMButton(134)
DoOEMButton(135)

What about the REF Z button on the Diagnostics Screen?
When pressed, nothing happens and nothing shows in the console.

Dennis

[TomKerekes]

Do you have the axes enabled under:

Config | Ports&Pins | Motor Outputs | XYZ Enables ?

Mach3 requires the axes you are using to be enabled. If you don't need or use the enables set as port 0.

Regards

[nova24]

Tom,

I'm thinking you may have stumbled across something. If you look at the attached image you'll see that everything is still set to zero. I left it this way because I can jog the axes from within Mach just fine. Is it possible that Mach is not passing any homing commands because, even though the axis is enabled, it doesn't know where to send the commands?

Thanks,

Dennis

[TomKerekes]

No I have mine set to all zeros and it works fine. They must be enabled though.

Please send me your Mach3 XML so I can test if it works for me.

Regards

[nova24]

Yeah, Already tried setting the ports and pins and still the homing didn't work.

Here is the profile I'm using.

Thanks,

Dennis

[TomKerekes]

You have a bunch of Limits and Home inputs enabled in:

Config | Ports&Pins | Input Signals | X++ X-- X Home ....

Try disabling them.

Limits and Homing are all handled by KFLOP. Apparently mach3 refuses to home if they are already indicating at Home.

Regards