Messages

511

General Mach Discussion / Re: UK Mach3 workshop

« on: June 17, 2008, 04:08:47 AM »

I hope not - Dave Waterworth mooted the idea, I don't know how far he has got.

512

General Mach Discussion / I am a complete *****

« on: June 16, 2008, 02:21:07 PM »

I have been messing about - and it was messing about with various screen sets - looking at the various choices to download.
I must admit that I didn't really fancy any in relation to the standard Mill and Turn Screens.

Unfortunately when I now click Mach Turn - the screen doesn't come up - and I have to find it and load it  using View/Load Screens.

Where do I tell my XML file the path for the screen set, or where do I put my lset file so that Mach ppicks it up as it starts up.

Jim

513

General Mach Discussion / Re: My Fixtures are not "fixing"

« on: June 16, 2008, 02:05:29 PM »

Yes - I was using the numeric keys above the letter set. This gives the effect I was talking about .

If I use the number pad, I can get the numbers 5 and 9  to register, if the number lock is one way (sorry I don't know which). If I toggle it the numbers don't register.

So I can get there if I need to.

Thanks Brett

 

514

General Mach Discussion / Re: cable question

« on: June 15, 2008, 11:56:18 PM »

Are you getting a new computer to run this, or using the existing one, with Windows installed.

Hood - If a new computer is on the cards I was thinking that Smooth Stepper would be a quick and effective solution - but you are the expert on that.

515

General Mach Discussion / Re: My Fixtures are not "fixing"

« on: June 15, 2008, 11:49:13 PM »

Yes - exactly that. I have just tried it again now. Started up Mach 3. I have the fixture table filled with offsets.
On the MDI page, I type in G55 - fine -up comes G55 right up to G59.

I type in G and 5 and as soon as I type the 9 the MDI line closes.

This is my office computer - using Mill. I haven't tried it on the workshop computer.
I know the G59P7 and P8 work in a GCode program, because I was using it yesterday, so I am at a bit of a loss. 

516

General Mach Discussion / Re: Matching Dros

« on: June 15, 2008, 11:39:55 PM »

This is exactly what I was saying (even with the correct numbers in). In actual fact there are not that many combinations of steps per inch.

Micro steps might change - depending on your cards ( some can do 1/2 steps right up to 1/16th steps) - motors seem to generally be 1.8degree these days - fixed at 200 steps per rev.

The difficulty might lie in the leadscrew. In Britain, although in theory we went metric many years ago, we never did, and all we have now, instead of one system, we have a metric/imperial mash. We have things that are sold as 8 feet by 4 feet in the building trade - and they turn out to be 2400 by 1200mm - i.e. short. I regulary buy 10mm bolts, the head on which should be 17 mill hex - the head turns out to be 5/8 inches.

I can see leadscrews in that sort of thing - marketed by some as 1/10 inch pitch, but being 2.5mm - it might not be as bad in America.

All I can say to Mr Cousins is - I hope you are following all this - it has certainly got a bit off the matching DRO's we started with. I think the pictorial by Rick spells out what I have been saying. Check your leadscrew with your manufacturer and see exactly what pitch it is if you are in doubt, and work from there.

517

General Mach Discussion / Re: Explanation of "Charge Pump" needed

« on: June 15, 2008, 11:14:12 PM »

You seem to be a bit at odds here. The charge pump system does not need any M Code to activate it. It is automatic as your machine starts up.

As Hood expained the charge pump gives out a signal to your stepper motor ( or servo motor ) drives not follow any signals until Mach 3 is properly unstalled and up and running. It only works if your driver cards support it. When Mach is turned on the signal ceases and the drivers then respond to control signals.

Are you talking about then turning on the machine - i.e. doing some work with it - in a program and activating the spindle, an M3 or M4 command.

If you have Mach 3 installed on your computer, you can test the four output pins by allocating them to M3 and then typing in the M3 command on the MDI line (page 2 of the Mill screens).  M3 should turn the pin on, M5 should turn it off.

If you are only using pins 2 to 9  for three axis, you will have two spare output lines there as well. You can also use these.

518

General Mach Discussion / Re: wiring diagram for limit switches

« on: June 15, 2008, 11:04:56 PM »

You do not need any if you have a "dead" breakout board, because the LPT1 port has built in pull-up resistors.
You may need one at the "pin" end of your breakout board - depending on how it is configured - you will have to read up on it.

The idea is the pin is normally +5v. The path through the series of switches to earth holds it at 0v until one of them (and as Hood said - you can have as many as you like) opens, and cuts the 0v path. The pin should then go to +5v to give a signal to the computer.

Some breakout boards have isolators on them, and the pin out voltages are reversed i.e. where they are normally held to 5 volts (from the computer) they are at 0volts on the breakout board. If this is the case you can either use a pull up resistor to pull it up if a switch is activated - or instead of the last switch being connected to 0v, connect it to 5 volts - so that the idea of the series path is the same, but just operating in reverse - normally held at 5 volts,  when the  series is broken it drops to 0
Mach 3 can cater for both systems.

519

General Mach Discussion / Re: My Fixtures are not "fixing"

« on: June 15, 2008, 02:56:38 AM »

I woke up this morning with the answer.

When on "Machine Co-ordinates" the DRO shows that figure, which it gets directly from it's own internal DRO. When you are looking at program co-ordinates, it gets the "Machine Co-ordinates" and then looks to see what the active offset is, and then adds (or sudtracts) that.

The problem is we can change the program co-ordinates on the screen - but Mach must still satisfy the equation. It cannot change the "Machine Co-ordinates" so it does the only other thing, and changes the active offset.

The only way to get round this is to use an offset as a gash one, and select this first, before you change any DROs. On page 2 of Mach - Midi Alt2) there is a DRO for the Work Offset. Putting a 1 in there selects G54, which I suppose could become the gash offset.

There appeasr to be a fault in the MDI line, because I cannot get it to take G59. As soon as I type the 9, it clears. Therefore on the MDI you are limited to G54 to G58. It will take a number in the Work Offset though and select all the g59 offsets as well.

520

General Mach Discussion / Re: Matching Dros

« on: June 15, 2008, 02:38:09 AM »

I will only say this once again, then I shall have to withdraw from this post.

If your calculated number of steps per inch is 20,000 - and that calculation is correct, then, despite what you say, measure or otherwise arrive at, that is the number of pulses that will give you the correct one inch of travel. Your figure of 20,000 would seem to be correct. Mine is 60,000 but I have 3 to 1 gearing on my leadscrews. It would seem you have Gecko drives (or similar) with 10 microsteps, you have 1.8 degree motors, and a 1/10 inch pitch leadscrew. Now - the only one of those that can change is the leadscrew, and I have never heard a lathe manufacturer who produces a leadscrew of 0.1048 pitch. Even if the leadscrew was a 25mm metric masquarading as an imperial screw, the pitch would be 0.1016.

You have arrived at your 20,967 by some sort of measuring - and it is incorrect. It may be you have run the table left, set everyting to zero, then run the table to the right for one inch measured by one of your  measures and gradually increased the number of steps till you got an accurate reading. The problem there is backlash - and you appear to have about 50 thou (same as me).

If you are taking measurements, you must always move the table in the same direction. Enter 20,000 as your steps per inch. Move the table 1/2inch right to get rid of backlash, then set up your DTI and zero it. Now move the table to the right again. If you use a G1 command, you can specify the feedrate f say at 4 to keep speeds low so you dont miss steps, and when Mach tells you it has moved 1 inch check your DTI It should be correct to within 1 thou - maybe 2. Move the table another inch to the right - now two inches, and check with the DTI this should also be accurate to within a thou or 2, because errors do not accumulate.I used digital calipers to check mine, and could do up to 5 inches. I don't know what measuring equipment you have. I am a bit reluctant, but I suppose you could use your secondary scale.

If the error using such a method DOES NOT accumulate - i,e, you were 1 or 2 thou out every time over the length you checked, then your pulses per inch are correct.
If the error KEPT INCREASING  each inch of travel, then your pulses per inch was incorrect - and I will stand corrected.

That is all I can say. I will read the post with interest to find out what the answer is.