Hello, I'm new to the board, but not Mach3.  I owned a couple of Mach3 powered mills that I sold about 3 years ago, and am building another now for personal use. 

I know someone had a board that would use the Z axis encoder pulse to home the axis, I've looked, and as far as I know, they don't sell it anymore.  I had a couple of Mach3 powered CNC Bridgeport mills, and other than the normal floppy BP frames, I could hold .0005 which was required some times.  My only complaint was the limit switches that I used for homing the axis, they would only repeat +/-.002" at best. 

Mach3 seems to have made leaps and bounds since then, seems like the imagination limits possibilities at this point.  Being familiar with PLC's, I don't see how BRAINS can't be used to make an encoder driven "axis home". 

I was wondering if anyone has a direction to point me in before I try trial and error.

Thanks
MC

Brains isn't a PLC it has a lot of limitations and quirks.

BUT IT can be done (;-)  You just have to figure out HOW to drive the axis to the index signal.

(;-) TP

I was wondering if anyone has a direction to point me in before I try trial and error.

I use vbs macros to home the machines to index pulse on the servo encoders.

I have connected the index pulse with the probe input in Mach3. So if we do a G31 command then it will stop on the index pulse. What I do is home the machine axes using home switches first  (VBS command DOBUTTON(24) etc.). Then do the G31 for each axis.

Hope I made it clear. If you need further help I can send the vb script I use in the home macro.

Zafar

Zafar that is interesting I would like to see that script. Cool idea. I was thinking of replacing a couple of large slaved steppers with AC servos and that would work well for my needs.

Thanks
Craig

Zafar that is interesting I would like to see that script. Cool idea. I was thinking of replacing a couple of large slaved steppers with AC servos and that would work well for my needs.

Thanks
Craig

Here's a part of the macro for z-axis. You can repeat it for the other axes.

DoButton( 14 )
DoButton( 24 )
DoButton( 24 )
While ismoving()
sleep(50)
Wend
code "g91 g31 z-2.6 f50"
While ismoving()
sleep(50)
Wend
setmachzero(2)

IF you plan on doing any probing or TLO that will not work out well as each time you rotate an axis motor you will trip the Probe input.

Just a thought, (;-) TP

If I am doing probing on the same machine then I connect the probe hardware through a relay which is enabled by an extra output pin. It cuts off the encoder index from the probe input pin and connects the probe to it. .

Zafar

chhaaaa gya ustad...well done... someday i wish learn all that stuff from u zafar..