Messages

741

General Mach Discussion / Re: How to wire steppers???

« on: April 04, 2008, 04:44:59 AM »

Having a devil may care attitude to money - I am going to wire up the leadscrew motor in parrallel and see if the driver will run it without  having a terminal thrombosis.

On a serious note - I put my meter in line with the motor card supply and then jogged up and down. I appreciate it might draw a bit more when working, but jogging (wired in series) the motors only draw 0.5 amps. Even if that went up to 1.5 amps under load, I will still be under my driver capability, even wired in parrallel.

I'm going to try it and see what happens.

The little Chinese man in Wales might get some more trade.

742

General Mach Discussion / Re: Hello 1st post, need advice on controller, board, drivers

« on: April 04, 2008, 04:05:53 AM »

I got my hand slapped the other week - you need to re-size your pictures to 800 x 600 pixels - any of the cheap picture editing programs will bo it.

If not, download a freeware version from the internet.

Before you can get good advice, you really need to make your own mind up about what result you want to see.

My own system is as simple as it gets. A lathe/mill driven by home installed stepper motors. No measuring device or feedback, I don't bother with limit switches. My speeds are very modest. ( That said, it does the job - and I can keep my eye on it when I am running)

I am quite sure - in fact I know - that other contributors have very fast moving, large machines, they need all the safeties (and in an industrial set-up they are probably mandatory)

I am familiar with Bridgeport mills - and the older ones tend to be large, slowmoving machines - very accurate etc. is it for industrial use, or the home workshop environment.

You have probably read the Mach 3 stuff over and over again, so you will know what Mach 3 can do. I would suggest that, for ease of use, you hold on until the Smooth Stepper is available ( coming soon from an outlet near you ), because the lads that have tried the pre production stuff say it is the bees knees. I anticipate - although I have not seen one, that this will give all the inputs and outputs necessary (and a few more besides) to wire to your lathe/mill in any configuration you want, and the only connection to your computer will be a USB lead - rather than having to mess about with the old LPT1 lead and a breakout board (which is limited and then you need other boards etc etc)

In the meantime, I would suggest you contact the makers of the motors, you say they are nearly new, and ask them what drivers and power supply systems (and more important, control systems) they recommend for them. They made them, they should know, and quite frankly, they are nothing to do with Mach3 (I don't mean that rudely). They are a bit of the machine - and that varies in all our different applications. As "Ssheidenr" said - if they are working now, something must drive them - and if they are CNC already, that probably Mach can deal with them.

If they are steppers - fine, I know about them, but I know nothing about servo motors and linear feedback instruments. The thing I do know is that Mach can deal with both easily (and does).

The spindle can be dealt with equally simply - I had to install a new three phase motor, but after that a commercial (Omron) inverter solved my control problem and Mach 3 was able to interface with that simply and easily. You might find that an inverter ( you may already have one) is fitted and you can connect speed control from Mach to your machine without any further interface.

As I say - I think the answer is up to you - how do you see it progressing.

After that, anything we can do to help.

743

General Mach Discussion / Re: M3-M5

« on: April 04, 2008, 03:59:26 AM »

See Config/Ports and Pins/Spindle Setup.

You can configure the delay to what you want for M3,M4 and M5

744

General Mach Discussion / Re: Why do large files cause lost steps?

« on: April 03, 2008, 04:36:25 PM »

There must be a limit to the computing power - at the moment Mach also generates all the drive pulses for the cards. I understand this will alter with the introduction of "Smooth Stepper" where the drive pulses are generated on the card. This will decrease the demands on computing power.

No - I don't think the demands are outrageous. I assume your PC is a stand alone, doing only the one job, - but when you are doing intricate work, as you say, with many little moves, at high speed, then the demands clearly rise.

The "look ahead" is the number of lines of code that Mach3 pre digests so to speak. I dont know how far it goes. I assume with some small files, it can pre work all the code and hence display the tool path from the start. Turning the tool path off shoud help as Graham said.

I would still consider increasing the RAM of your machine, but look out for the smooth stepper - perhaps some of those testing them will let us know if it would help in this case.

745

General Mach Discussion / Re: DRO # for Steps Per Inch/mm

« on: April 03, 2008, 04:25:35 PM »

The function is

GetParam (name as String) as Double

The string you want is "StepsPerAxisX"  or Y or Z etc.

746

General Mach Discussion / Re: How to wire steppers???

« on: April 03, 2008, 04:06:40 PM »

Thanks to the two Ians and Hood -

Yes - Fired up from the replies I went in the workshop and had a fiddle. I tried altering the incremental steps. I seemed to get more speed from 1/2 step. Full step was a bit too rough. I upped the speed to 10 ins per min. I got the crossslide travelling at that speed but the leadscrew baulked at it.

I get the idea that there is a bit too much resistance for it to accelerate up to top speed. I've tried to adjust the acceleration with some success, but not reliable. I think as Hood said, I could do with a bit more torque to get over the sticky patch.

My motors are wired in BiPolar series, i.e. coil A to coil C  (A - A' - C - C')  and B to D.  The coil resistance is (across two coils in series) 5.8 ohms, across one coil is 3 ohms. This relates to the information about the motors - 2.5amps at 7.5 volts - which is on spec exactly.

My problem is, of course - if I now wire them in parrallel the net resistance will drop to 1.5ohms. I don't know enough about the makeup of stepper motors to know - if I run them at 24 volts how much current will they draw - my drives are RoutOut CNC and in the data sheet are rated at 2.5amps.

747

General Mach Discussion / Re: How to wire steppers???

« on: April 03, 2008, 06:00:14 AM »

The driver cards are marketed by Routout CNC shop in Wales - don't know where they are made - see Ebay.

Are the Welsh related to the Chinese???

Yes - that is what I though about the steppers - in parallel they will draw twice the current, so should give more torque - but I couldn't see an increase in speed.

I would try it, but the drives are rated at 3 amps max, and the motors are 2.5 amps per segment (7.5v). I am running on 24 volts and I am wondering if they will draw too much current and blow the drive

748

General Mach Discussion / Re: About "slow jog" button.

« on: April 03, 2008, 03:54:14 AM »

Set the "slow jog" at the speed you want when, say, moving the tool to a precise point. I have mine a 10%

To jog at full speed - i.e. that set by your motor settings, press the "shift" key whilst pressing the "jog" key.

749

General Mach Discussion / Re: Why do large files cause lost steps?

« on: April 03, 2008, 03:46:29 AM »

Whilst I haven't much of a clue - I might give you some general pointers - I hope you haven't thought of all these. I have looked at your web site and if some of the intricate designs on there are anything to go by, I can see what you mean.

As far as a rotary and linear axis is concerned, I cannot see that this should be any problem - both are driven by stepper motors - I assume within the limits of the motors themselves. The only difference between a linear and rotary axis is that they do not change units when switching from metric to imperial or vica versa.

When you say you have built this machine recently - I take it you have not needed, or got switched on, the backlash feature.

Yes - when you are making many tiny moves, the computing time needed shoots up. I do not know which mode, CV or Absolute stop, uses more. In Absolute Stop  the axis literally stop between each move, then accelerate again - hence the jerky movement, whereas in CV the computer has to calculate similar acceleration and deceleration patterns for the two axis as they move, and introduces the next movement as it slows the previous one. Upping the "look ahead" facility - the number of lines Mach3 computes in advance -  might be some help here

There has been mention in this forum some time ago of the screen redrawing interfering with running - particularly of large files. I didn't note how to turn iit off because it didn't apply to me - but no doubt someone will be able to tell us.

On a simple note - is your computer up to the job. The speed of the processor is quite clealry fundamental, but more so the RAM memory is critical in computing speed - and is a simple way to try and improve, without costing a fortune. I am a member of a theatre organ forum - computer based - and the difference in performance between 256MB and 2GB is astounding. No doubt you have a large memory, but I would up it to the maximum and see if that gets the processor working faster.

I hope some of this helps you find where to look.
 

750

General Mach Discussion / How to wire steppers???

« on: April 03, 2008, 02:53:16 AM »

I'm trying to speed up my axis a bit - well a lot actually, since I cannot move them above 4in per minute at the moment.

Up til now, I thought it might be a mechanical problem with the lathe, but I took the belts off the motors and tried them on their own. I can't get them to spin any faster on their own.

I am running 1/8 step, 1.8 degree, 3 to 1 reduction, 1/10" leadscrew which, I think gives me 48,000 pulses per inch and therefore 192,000 pulses per minute for travel.

The motors are Arc Euro Trade Hybrid Steppers - 220Ncm, 2.5amp 7.5volt - and all in all I am satisfied with them - they are certainly powerful enough to do the job and at £22.95 each are relatively cheap.

They are 8 wire motors - and I have wired them in series.

The $64,000 question is - will they spin any faster if I wire them in parrallel - or is my computer - a Toshiba laptop - just up to its limit (says he looking longingly at the USB driver board just announced).

Anybody any ideas???