Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: camcut on October 17, 2007, 05:05:25 AM

Title: Running 4th axis independently from xyz
Post by: camcut on October 17, 2007, 05:05:25 AM
Is there a way to run a fourth axis continuous and independently from xyz axis within the Mach environment?
At present I have a large motor running a slow turntable within the xyz envelope but I would like to
replace this with a smaller one and wondered if I could use a stepper motor.

Tom
Title: Re: Running 4th axis independently from xyz
Post by: bowber on October 17, 2007, 12:02:49 PM
If I understand this correctly you need to be using the A axis, you'll need a driver for the stepper and set up the axis in Mach but this is the normal way.

Steve
Title: Re: Running 4th axis independently from xyz
Post by: vmax549 on October 17, 2007, 01:56:16 PM
Out of curiosity(;-)  If you need it to run independant and continuosly why would you want Mach to control it??

And I believe the answer is no, unless you just want to turn it on or off then you could use Mach to trigger a relay to do that for you.

(;-) TP
Title: Re: Running 4th axis independently from xyz
Post by: camcut on October 17, 2007, 04:58:04 PM
Thanks for your comments.
If it was possible to run the turntable with a stepper motor I could use it as if it was a lathe but could also use it for indexing. At present I would have to remove the motor and turntable to fit a rotary table for indexing which would be avoided if there was a way to use a stepper motor. But I guessed it would not be possible.

Tom

Title: Re: Running 4th axis independently from xyz
Post by: vmax549 on October 17, 2007, 05:30:08 PM
NOW that said never say impossible to this group(;-) let them think about it for a while, you never know what may pop up.

Indexing would not be a problem as an A axis. And you could use the swapaxis() command to swap the spindle over to the A drive if setup to do so.

 You could also have multi configurations of mach but to have it all at one time is still pretty much no.(;-)

(;-) TP
Title: Re: Running 4th axis independently from xyz
Post by: Chip on October 17, 2007, 05:34:57 PM
Hi, Tom

One way is to use a DPDT ON ON switch, Run your rot. table step & die  wires to the center terminals, Mach3 A axis S/D to one side of the switch and a LM555 oscillator to the other side.

This would allow you to set a cont. speed for your spindle/rot. use and switch back to A axis use.

PM your phone # if in USA / CA, I'll give you a call after 9:00 Eastern tonight.

Thanks, Chip
Title: Re: Running 4th axis independently from xyz
Post by: camcut on October 18, 2007, 05:05:48 PM
Thank you vmax549  and chip for your encouraging posts.

I am from England so phone call is out, but thanks all the same.

As I have no experience in electronic  I do have problem to understand unless descriptions are thourough and clear.
This evening  I spent reading up about switches and LM555 and I believe I should be able to obtain these within a few days.
I did not build the electronics on my cnc unit but bought a plug and play unit with motors readyl wired, hence I am uncertain about wiring the connections.

I have made a diagram which I hope I will be able to attach. It shows the existing wiring between the z axis motor and the controller.
Would it be possible to indicate which wires goes to which terminals.

Again many thanks Tom

 
Title: Re: Running 4th axis independently from xyz
Post by: Chip on October 18, 2007, 09:11:13 PM
Hi Tom

How big is the table and motor ?

There are a couple of stepper boards that have the Timer built in.

I need to dig around hear and find the info, Mostly for small steppers, NEMA 23 size motors.

Hears a basic diag.

Thanks, Chip
Title: Re: Running 4th axis independently from xyz
Post by: chad on October 18, 2007, 11:47:06 PM
Here is a great page on the 555.

It has more that you would ever want to know about the 555. Look at the Astable oscillator calculator.

http://home.cogeco.ca/~rpaisley4/LM555.html#3

chad
Title: Re: Running 4th axis independently from xyz
Post by: camcut on October 20, 2007, 05:37:02 AM
Hi Chip

The motors are DCNC -57-610-01 (1Nm) and the ball screw size are x axis  880 mm  y axis 800mm.
I do not know about the timer and the board.

The information I have on the board is:

2.1 Amp bipolar chopper driver
Step direction type controller
0.4 A up to 2.1amp/phase max bipolar
up to 44v motor voltage
logic TTL compatible 5v
Two different chopper methods
motor current & chopper frequency easily set with trim pots

Hi Chad
Thanks for the link.

For all you not in the know England has a rugby match tonight. It probably is not a big deal in the wide world but it seems to matter big time in the UK.

Tom


Tom