Messages

351

General Mach Discussion / Re: Basic initial setup question

« on: August 21, 2008, 02:21:52 PM »

What you need to do - say re the toolpath window question - is look at the video tutorials, which are very good. You could (at one time) download them, I'm not sure if you still can, but they answer so many simple little questions, and quite a few you didn't think of.

352

General Mach Discussion / Re: Basic initial setup question

« on: August 21, 2008, 02:18:47 PM »

To set up your soft limits you need to "map" your table - so you need to set up a point to which you can return confidently - say the bottom left hand corner - with your cutter on the table. (This is only an example - and it can be anywhere - but should be repeatable, not necessarily to any great accuracy, but reasonablly so.) You are in fact making your own home position - and then "Ref All Home".

Your Machine Co-rds  DRO's will all go to zero.

Still watching the Machine Co-ordinates then jog your table to it's extremeties and make a note of the DRO reading - same with your z axis. Set your soft limits to these values (or just short of them) - in the machine set up units (ins or mm).

The reason your machine was doing unpredictable things is that it did not know where it was - or it thought it was somewhere ither than the place you thought it was.

353

General Mach Discussion / Re: Basic initial setup question

« on: August 21, 2008, 02:07:58 PM »

Machine co-ordinates - these are co-ordinates that Mach keeps track of so that it knows where it is. You cannot change these directly. If you press the Machine Co-ordinates button the button surround will light up. The DRO's are now displaying machine co-ordinates.

The only way to change these is with the "Ref All Home" button.  If you had your home switches connected (which you haven't) what you would see is the machine move in turn to each of the home switches, and stop there and the DRO would go to zero. The machine is now "homed" and Mach 3 knows where it is.

If you do not have switches, or they are not activated, then the DRO's will go to zero, without the table moving. (But that is not much use)

Program Co-ordinates - these are displayed when the Machine Co-ordinates button is pressed and the surround light goes off.
You can zero the program co-ordinates at any time by using the zero buttons. If you do this so that the Machine Co-ordinates and the Program co-ordinates bith display zero - then the difference will become obvious.

It is unlikely that the posittion in which your home switches are set is any use for machining components, and will almost certainly not be the position that your program calls 0.0.0. (for mills this is usually at the bottom lefthand corner of the workpiece, with the cutter resting on the top of the workpiece - BUT NOT ALWAYS SO). You must find out where your program thinks it is for position 0.0.0.

If you are displaying Program Co-ordinates, then jog the axis to the correct position to start your program - and zero the DRO's.
If you change to Machine Co-ordinates you will see that these have not changed. If you look in Config/Fixtures you will see that the default config G54 has changed and contains the co-ordinates that your Machine Co-ordinates are displaying. These are the offsets between Machine and Program Co-ordinates.

What does this mean -???

What this means is that (If you have the offset stored in one of the other offset slots - G55 to G58 and G59P7 to G59P255) if you zero the machine by "Ref All Home" then if you have the offset written into the program e.g. G55 then the machine will move to the correct position to start the program. All your programs can have different offsets if you need them (there are about 256 of them) or they can have the one offset if you always use the same work piece holder etc.

You can introduce other offsets into the program, and say run the program 3 or 4 times, using a different offset each time, and therefore cutting identical work in 3 or 4 different places. (My CNC man with a big machine does this quite often - He has 4 vices on the machine and puts work in each - the machine then cuts the same pattern at each of 4 places - it saves him changing the workpieces everytime.)

During all this your machine still keeps track of its movement in Machine Co-ordinates but the Program Co-ordinates display enables you and I to look at the DRO's and make sense of what we see - since it should at any particular line display the co-ordinates that line is in the process of cutting - or a position at which it is drilling etc - and we can compare this with the program immediately.

I'll now have a lok at the rest of your post.

354

General Mach Discussion / Re: Progressive Move Error with X and Y

« on: August 20, 2008, 04:40:52 AM »

Carl - sorry but Ive been away and lost the drift of this post.

It seems that you are trying to wire your computer direct to your stepper drivers. You say it will not work.

The 25 pin port for the printer provides the 17 data pins and the 7 signal return pins (essentially the 0v of the computer). No +5v signal is provided.

The leads from your port must be three to each driver card - step, dir, and a signal return (0v) for reference, otherwise your driver card cannot sense the voltage on the step/dir pins.

For some driver cards that is sufficient - they require step/dir and 0v.

Some, like my Gecko's require step/dir and a +5v  reference.

For this you need a seperate +5 volt supply (seperate from the motor power suppy that is (not derived from it)) I used a small telephone charger unit with a 5v regulator.

The signal return wire from the computer goes to the 0v of the 5 volt supply, and the +5 volts wire goes to the driver card.

See the attached diagram

355

General Mach Discussion / Re: Difference between STEP and DIR

« on: August 20, 2008, 04:06:07 AM »

You will find that an UNPOWERED BOB board will be fine. There is no interference with the signals, and they are cheaper.

Provided you have a SEPERATE 5 volt power supply for your home and limit switches, and your M3,M4 M5 relays and coolant, you will be fine. (SEPERATE  from the MOTOR supply, that is).

356

General Mach Discussion / Re: Difference between STEP and DIR

« on: August 19, 2008, 02:27:11 PM »

Try wiring your step and dir wires DIRECTLY to the driver board, and miss out the BOB board.

We have had previous posts where CNC4PC have had funny results. I think it is the Opto electronics that slow down the pulse.

357

General Mach Discussion / Re: M3 / M5 execution delay

« on: August 14, 2008, 09:54:38 AM »

Why not just use a macro to turn on your relay or whatever.

Instead of M3 and M5 use M*** and M*** to turn it on and off. The other alternative is to use the coolant outputs - there is no delay on that (that I know of).

The delay, however, might be due to the visual basic interpreter. What about a brain (which are much quicker)

358

General Mach Discussion / Re: more inputs possible?

« on: August 13, 2008, 02:19:23 PM »

yes

you might have read that on the internet, what I am saying is check BEFORE you buy it.

If it is truely bi-directional you will have no problems. All pins can be inputs or outputs.

Depnding on how much you want to spend, you might consider getting a Smooth Stepper which has all the inputs and output ports you will need, and also has the pulse generators for your stepper motors/servo motors and saves your computer all the work of generating the pulses itself - leaving your computer free for other things.

It plugs into a USB port and so will save you the problem of taking your PC to bits. It drives the stepper motor cards through a breakout board, or directly.

359

General Mach Discussion / Re: more inputs possible?

« on: August 13, 2008, 12:34:18 PM »

You are wrong with your pins - There are 5 inputs - 10,11,12,13,15  Outputs 1,14,16,17.  and 2 - 9

These are the in/outs as fixed on the standard LPT1 printer port by IBM when they first invented the IBM PC.

If you get extra boards, and they fit in your computer, then (and you MUST read the paperwork with them) some can be programmed to be inputs or outputs, just as you wish.

Some CANNOT and they are made to be the same as the LPT1 port - you must check before you buy one.

Mach 3 can use either board.

360

General Mach Discussion / Re: How to use the macros£¿£¿

« on: August 11, 2008, 12:50:07 PM »

Edison - You appear to have some (to us) special characters on your keyboard which make your message a little difficult to understand.

However -

Your first two queries I do not understand - how to "shield" cycle start
and how to set up "regularly interrupted"

In the macros, you can write any function. The Macros are in Visual Basic and there is a link with Mach 3, so many of the functions performed by Mach 3 can be recalled in Visual Basic. There is a list.

"Is moving" means If an Axis is moving - and the full instruction  "Whilst Is moving" and  "Wend" - means while an axis is moving wait until it has finished, then move on to the next line.

If you can expian your first queries, we will try and sort them out.