Y with A as slave axis won't work

[chillybo]

Hi guys, I am baffled after checking wiring and settings over and over. I have decided to try using dual motors on my Y axis but can't get the new motor to slave (Mach3 CS labs I/PM). I selected Config / Slave axis and selected A in the Y box then restarted Mach3. Then I made sure Y and A motor tuning was the same. I enabled pins 7 and 8 for the A axis and then selected home slave with master axis in the general config.
The new stepper turns when I jog the 4+ / 4- button and also works when I set the steps per revolution function. It doesn't work as if it is slaved with Y though.
Could anyone please suggest what i am doing wrong? Is it a Mach3 setting or something to do with the I/PM controller?
Thanks Chris

[JAZZCNC]

You don't set the slaving in mach3 Config/Slave axis you set it in the Cslabs Plugin. Go to to Config/Config plugins and select the Cslabs plugin and do it from within there.

[chillybo]

Once again thanks Jazz. It's fixed. I couldn't find anything in the manual about controlling slave axis within the IP/M plugin.

[chillybo]

How do I go about using the Mach3 steps per revolution function with slaved motors. If I use it do I just calibrate the Y axis? I suppose that this is the only way it can work?
Thanks ...Chris

[JAZZCNC]

How do I go about using the Mach3 steps per revolution function with slaved motors. If I use it do I just calibrate the Y axis? I suppose that this is the only way it can work?
Thanks ...Chris

Just set the Y-axis steps per and the plugin will deal with the other axis. The only thing you need to do in Motor outputs is to enable the slave Axis.
Be aware that with the IP/M you can't home each motor to its own Home switch so you can't square up the gantry using the Home switches and in ports n pins you only set the Home switches for Y-axis.

[chillybo]

Thanks Jazz, It's working fine now. I have read the other thread on this forum about how the IP/M doesn't have gantry square correction but I can't see it being a problem. I'l just keep an eye on the gantry and if needed undo a coupling and adjust a ball screw by hand to square it up every once in a while.
Thanks ...Chris

[Neale]

It's easier to just drop power to the drivers so the motors can turn and just turn the screw by hand. I had a home switch on A as well as X and used that to do manual homing of the slave axis using the led on the proximity switch. It's not absolutely exact as the motor will them jump to the nearest full step when you reapply power but that's not really a big issue on the kind of machine that uses a gantry (I.e. for woodwork).

You do have driver stall detect wired back to the ip/M, I hope? This means that if one motor stalls, the machine doesn't try to wind the gantry off the rails!

Written by ex-IP/M owner...

[chillybo]

Driver stall detect? How does this work?
I can remember reading a thread on another CNC forum where an American chap with slaved Y ballscrew said he used a belt between each ball screw as a safety measure. When he powered the machine down everything kept synchronised and if anything went wrong while it was running at least it wouldn't twist the machines frame.
Just a thought?

[Neale]

On modern digital drives (I use EM806) there is a stall-detection capability. Typically, if a motor is stalled at above about 300rpm, the drive stops and enables the fault output signal. You can use this to tell the motion controller that there is a fault so that it then stops driving the other motors. My drivers are configured with all the fault outputs in parallel so that if any one trips, the machine stops. This is useful on a dual-motor gantry machine. Joining the two ballscrews with a belt won't achieve this. On the IP/M I think you use the "servo fault" input.

[chillybo]

Just had a look at the EM806 they've got a couple of extra connectors on them, I'm assuming this is for the stall detection output?
My stepper drivers are DMA860H ones that don't appear to support this function.
Thanks ..Chris