Messages

701

General Mach Discussion / Re: I have not been able to find information on this automatic zero/ height method

« on: April 16, 2008, 03:45:28 AM »

Pardon me asking - but are you trying to build a retractable undercarriage for the jet - using stepper motors driven by the board you had photographed.

I only ask, because I cannot see how Mach3 can help??? I can understand the stepper driver board - it is simple to connect and reliable, but unless you have an on board PC how can you control them.

Without being too silly - and you say electronics is not you, a Programmable chip would be the ideal controller for driving the Stepper board. It could put out the corect number of pulses to the board (up or down) - and mean that your radio control only had two signals to send - undercarriage up and undercarriage down.

Or am I (yet again) way off the mark.

702

General Mach Discussion / Re: increase the feed (accelerando)

« on: April 16, 2008, 03:29:40 AM »

I thought I had replied to this yesterday - I don't think so - but why do you need it.

Mach3 will respond to CSS - Constant surface speed - where you are taking a cut across the face of work on a lathe - and the SPINDLE will accelerate to keep the speed pf the work past the tool constant. I suppose, but have not tried it, that this would also be the same cutting a taper shape. For this, though, the spindle speed must be controlled by Mach3.

The problem is the GCode can only have one instruction (of each type) on a line - so one F instruction is all you can have. You could split the line into say 5 lines, and increse the Feed in each one, if you have Constant Velocity on the effect would not be too bad. - BUT why do you need it.

703

General Mach Discussion / Re: I have not been able to find information on this automatic zero/ height method

« on: April 15, 2008, 05:22:27 AM »

As far as I know the software for the "probe" is already in Mach 3.

Any "metal" object is placed on the table, and the tool moved to it. When the tool touches it, it stops. (The metal object must be electrically isolated from the table ) A wire is connected to the metal object and fed into LPT1 input pins and the Config/Inputs/Probe is configured as the input, "active low". If you notice a clip was put on the tool to help with earthing the "target" when touched, but apparently this is not always required.

There is a similar post submitted by Benny further down the main page "Check out this post"

This appears to be a very useful tool - can anyone tell us if this is in Mach3 - and what the syntax is

704

General Mach Discussion / Re: incremental feed

« on: April 15, 2008, 04:59:38 AM »

You do not say what you are trying to do.

If you are on a lathe and taking a facing cut across the work then you are talking of CSS Constant Surface Speed. This is available on Mach3 if you have the necessary control of your motor spindle.

Other than that I cannot begin to understand why you want to increase the feed rate - i.e. the speed the tool moves - as you progress along a cut.

705

General Mach Discussion / Re: big problem mach3 cnc

« on: April 14, 2008, 08:54:21 AM »

Stirling - You're not French are you - excellent reply

706

General Mach Discussion / Re: Help

« on: April 14, 2008, 08:49:15 AM »

So - you are getting movement be happy !!!

You now have to begin the hard work and set the machine up. We assume you must have done the Ports and Pins to get the axis moving at all. Go to Config/Motor Tuning and set up your axis motors. As a quick guide 1/8 step motors, 200 steps per rev/ 10 revs per inch = 16000 per inch. alter you figures to suit but that gives you the idea.

I don't know what machine you have but set the speed at a very conservative 5 units per min. If this works keep putting the figure up til your motors baulk at it and step back down a bit.
Set acceleration at 1, the pulse time at 3 SAVE EACH AXIS SEPERATELY OR IT WILL REVERT.

This should get you speeded up.
As somebody mentioned above - when jogging - have a look at the jogging %. This is the percentage of the speed you have set under Config. To move at FULL SPEED press "shift" with the "jog" key.

707

General Mach Discussion / Re: indexing

« on: April 14, 2008, 08:26:29 AM »

When you say an indexing head controller - do you mean using your lathe spindle to hold the work, then indexing it round, or are you taking about, say, a rotary table indexing.

The question is really - what method are you going to use to control your indexing head to make it accurate.

My lathe spindle and miller spindle both have an indexer attached which, at the moment, acts as a counter so that Mach 3 can keep track of the speed it is turning, it follows that this signal (which I think goes in on pin 15) also clocks at precisely the same point each time. It is fairly simple to achieve.

708

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

« on: April 14, 2008, 08:17:52 AM »

My apologies - four poles - two magnets.

I don't think we are going to resolve this unless the manufacturers give figures for their motors - all from the same Hymnbook.

If I can run a motor at different voltages - Routouts sheet with the driver say it is the normal to drive motors with 3 or 4 times the rated voltage, then how are we ever to know the current they will draw (at that voltage). I noted the figure given for the motors above and the current drawn by the various different wirings was in the ratio   Unipolar 4, Bipolar series 3, bipolar parrallel 6 - but in quoting the current, nowhere was an appropriate voltage quoted - except one, where the voltages were different for each method of wiring.

I think it is going to be a matter of intuitive guesswork - and a continuous check on the warmth generated to see if your setting have any adverse effect. Yes - I must admit I try and stay conservative - I am only a hobby/part time pro - I build maybe two engines a year - so I do not need to try and get every last ounce from the machine.

It would still be nice to know though - and to be able to advise others - what is the best way to wire steppers for the quickest, reliable performance,

709

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

« on: April 14, 2008, 04:20:32 AM »

You two chat amongst yourselves - I had the back off one of the motors - it fouled the lathe bed and cut the wires (lost a drive) - it needed re-wiring so -

It looked to me as though there were eight coils in my motor - wired as four pairs (one pairing the opposite).

On diagrams I have seen of stepper motors, there have always been four magnets - which mean that they must be seperately wound. If they make eight wire motors - they must be four seperate coils, but having said that - how you wire them gives several choice

710

General Mach Discussion / Re: DC Spindle drive question, What to do with it!

« on: April 13, 2008, 03:44:35 AM »

Graham - and Ditmar

I don't think you need to get too involved in how it all works. The important thing for you is What makes it work. You say it is a 10v dc signal that controls the speed and a relay controls the direction.

If there is easy access to the reversing relay already fitted, then this can be controlled by a second relay in turn  controlled by the Mach3 M3 or M4 signal (which would cut out any chance of electrical interference). Ditmar - as far as you are concerned - the same question - what changes your direction now - is it a switch, is it a pushbutton - etc. The simplest way to wire anything up is leave it as it is, and just alter the control - so if you have a switch - fit a relay that closes a switch in it's place. I have my four additional outputs on Mach driving four relays ( via a Darlington array chip) - a single chip that can drive all four relays direct from the computer. These relays are (at the moment) activated by M3 and M4 (to suit my Omron inverter). I am only using two at the moment - the other two are spare possibly for coolant and anything else I want to control.

As far as the control voltage is concerned, a simple digispeed card will convert the PWM signal output by Mach 3 into a control voltage of whatever voltage you want. The two halves of Digispeed are electrically seperate, the input side is powered from the computer electronics at 5volts. The output side power is taken from your controller which in your case shows 10volts. Digispeed therefore puts out a signal from 0v to 10v to control the speed.

The diagram you posted shows that the 10v supply is isolated from the rest of the drive circuitry - so I think you are on a winner - but I can't quite work out where the signal goes in to control the speed.

Does the system fire up as it is - i.e. does it run the spindle - I assume it must work - so how do you control the spindle speed now. If it is a manually potentiometer then you could replace that with leads to digispeed and it would run fine.

It is identical (and probably from a similar era) to my Omron (although mine uses 3 phase AC drive) but the controls are identical.

I have Digispeed fitted and you are welcome to have a look.

As far as the speed indicator working - mine is just a single strobe each revolution, - on the index pin. This is nice and simple. The lads who have used multiple slots had a bit of difficulty, and, I understand, one of the slots should be wider to index the position. The method you use is not important - both work. The important bit is the voltage that your indexer puts out. This should be TTL compatable so you can feed it into Mach3. I use reflective sensors - onto mirrors stuck on the spindles - with a disc you can use straight through sensors. Once you get the output voltage right you will have no difficulty.