Couple of questions re. Acorn

[SimonP]

Hi, I have been getting to grips with my Acorn set-up.
I have a few questions...,
In the wizard, how do I choose which of the axis drive types do I use for my hybrid stepper motors?
One of the drivers is a Longs HBS86H and the other is an Ebay purchased HSC86H.

My hybrid stepper motors have '1000 pulses per rev' encoders, what do I enter in the wizard for steps per revolution? 4000? why?

On the case of the drives there is a table that relates to the position of the DIP switches, do I set the switches to 1000 or 4000 or something else?

In the wizard, it lists the axes 1 to 4, I can't change the Axis letter in 1 & 2 (they are greyed out) whereas I have the option to change 3 & 4 i.e. axis X,Y,Z,A,B etc..

I have switches on the two axes on my lathe, the only way I can get the machine to home is to put the switches in series and connect to input 1 and in the wizard, select 'Home All'. But how do I make the same switches be seen as limit switches as well?

Sorry if these are basic questions, but I have scoured YouTube for some clues without avail..

[cncsnw]

My hybrid stepper motors have '1000 pulses per rev' encoders, what do I enter in the wizard for steps per revolution? 4000? why?

See http://www.cncsnw.com/Quadrature.htm

I have switches on the two axes on my lathe, the only way I can get the machine to home is to put the switches in series and connect to input 1 and in the wizard, select 'Home All'. But how do I make the same switches be seen as limit switches as well?

Unfortunately, that option is not provided via the Wizard. If you use "HomeAll", then you need to rely on your software travel limits (which you should set up, regardless) to prevent overtravel. The software travel limits, of course, will not be applied until the machine has finished homing.

You could wire your home-end switches to two separate inputs, and designate them "FirstAxisHomeLimitOk" and "SecondAxisHomeLimitOk" in the Wizard. Then the switches would function as limit switches, and stop motion when tripped even if the machine has not yet been homed.

[martyscncgarage]

Hi Simon,
We are happy to help if you can please provide more information about your machine, drives, links to manuals etc.
Take the time to follow this post:
viewtopic.php?f=60&t=1043

Knowing what you are working with will greatly help us help you.
Marc (cncsnw) pretty much answered your questions. If you have the available inputs, you can each axis as Marc suggested.

Marty

[SimonP]

Gents,
Thanks for your replies..
I have only just got to the point where motors are turning on the lathe and moving the axes, hence now I am trying to make the motors actually respond correctly.
I've resolved the home limit question by doing as Marc suggested and wiring the switches individually to inputs 1 & 2.
In the wizard, I cannot assign an axis to a letter for axes 1 & 2 though, the boxes are greyed out.. I have the option for axes 3 & 4, (N,Y,W,A,B,C)
I want to change axis 1 to X and axis 2 to Z, why can't I do that..?
I will try to upload a report next time, I don't have a thumb drive with me to transfer it to my laptop from the machine's PC...

[martyscncgarage]

Gents,
Thanks for your replies..
I have only just got to the point where motors are turning on the lathe and moving the axes, hence now I am trying to make the motors actually respond correctly.
I've resolved the home limit question by doing as Marc suggested and wiring the switches individually to inputs 1 & 2.
In the wizard, I cannot assign an axis to a letter for axes 1 & 2 though, the boxes are greyed out.. I have the option for axes 3 & 4, (N,Y,W,A,B,C)
I want to change axis 1 to X and axis 2 to Z, why can't I do that..?
I will try to upload a report next time, I don't have a thumb drive with me to transfer it to my laptop from the machine's PC...

In Centroid lathe, the software is HARD CODED, for axis 1 to be Z and axis 2 to be X.
Please wire your motors that way. I tend to wire the inputs that way too. Input 1 is Z and Input 2 is X but that's not as critical.

Marty

[SimonP]

Thanks Marty for your reply, sorry it's been a while responding..

I understand the X and Z axes are had coded in the software now, thanks.

I have been distracted by the issue of the toothed belts not tracking on one of my hybrid stepper motor and the spindle encoder.
I spent literally all day on it weekend before last and no matter what I tried (shimming the motor mounting plate one way then the other...) I just could not get the belts to stay tracking true and within the width of the pulley.
The pulleys don't have flanges on them to restrain the belt sideways, maybe I'll have to solve it that way..

[martyscncgarage]

One pulley no flanges and one pulley with flanges are generally needed. Make sure your pulley bored are running true to the shafts

[cxagent]

Simon - if you have not solved the belt tracking issue yet I would very carefully check the two shafts are parallel. Any deviation from the shafts being parallel will cause the belt to walk off the pulley. In some years ago troubleshooting, I found I could not eyeball / measure the shaft parallelism accurately enough but watching the belt tracking I could shim the motor mount to keep the belt on the pulley.

Now for my question - I am just setting up and wiring my CNC mill. I saw the Acorn board diagram that has all NC Home switches in series. Intuitively, I don't like that. It is fine for limit switches (any limit switch tripping shuts down motion) but for Home switches this seems like trouble. It seems to me that with the NC Home switches in series, the first axis to trip a Home switch would indicate to Acorn that ALL axis are in the Home position. Is there some software magic that sorts out which axis is in the Home position and which one(s) are not?

Asked another way - Is there a downside to wiring the Home switches to individual inputs like I am planning to do?

[martyscncgarage]

Home all works. It's in the homing program routine.
No problem with using individual inputs. But you may use up precious inputs that way.

[cxagent]

Thanks for all you do Marty.

Based on your reply I will wire all of the Home switches in series and see how that works. That one is easy enough to change later if I have trouble.