Messages

1161

General Mach Discussion / Screen enhancement for M6

« on: August 14, 2007, 07:13:50 AM »

I have altered the manual screen on the Turn program to include inputs for a tool change position, as in the video tutorials. I was hoping to put in a command such as M6 T3 - and the lathe would move to a change tool position, indicate on the screen which tool to insert, and also automatically change the offsets.

If I do such a command on the Mill screens, then this is what occurs, but the same Visual Basic file ( minus the Y axis ) does not produce the tool change required on the Turn screens. It quite clearly is not picking up the information from the command. I can put them in manually and all is well. Does Turn react to "GetSelectedTool ()" or is it something different. M6 is fine , it is the T? that is lacking.

I cannot access any customising information with Adobe reader to check this.

Jim

1162

General Mach Discussion / Re: Getting Outputs to work?

« on: August 11, 2007, 04:09:43 AM »

Pin 16  is a standard output pin and was to initialise the printer. Pin 17 is an inverted output and was a "select" output.
I would think that your computer would use these and it is difficult to see why anybody making a computer would take the trouble not to connect them - particularly if  you have the rest of the system working so well. The other "output" pins are 1 and 14, both inverted.

Try using these two and see what signals you are getting out. What are you using to check the outputs. If it is a multimeter, you will have to check against the negative rail (pins 18 to 25) because there is not positive supply available on the port.

I have pins 1 and 14 supply ( via transistors) a couple of relays to turn on the spindle, so these work.
Make sure you are counting from the right end of the plug, numbers 1 to 13 go along the top row but 14 is back to the other end on the bottom row (under number 1) - if you count from the wrong end you will only get the earthed or signal ground pins.
If you are stuck I will check what outputs I get on mine, but I don't have time right now.

You sound as if  you will have - but make sure your lead is fully connected.

1163

General Mach Discussion / Re: Help w/ Mach 3 programming

« on: August 09, 2007, 03:25:18 AM »

Have a look at the video tutorials, particularly the one on Lazy Cam. There is a bit in there about doing engraving and cutting out letters.

Unless you are prepared to learn G code, you will need a program that converts your  text to g_code.

1164

General Mach Discussion / Re: spindle encoder?/

« on: August 08, 2007, 12:03:59 PM »

Got my Fairchild encoders fro a British company - something robotics - paid by Pay Pal. A bit expensive - £2.50 each ( 5 dollars ). Got four, cost £13.50.

1165

General Mach Discussion / Re: Step losses in specific displacement

« on: August 08, 2007, 11:57:33 AM »

I still think this might be a power supply problem.

If you are running say G0 X10 Y10 from a position of 0,0 then as you say this is 45 degrees. Yours motors will be taking the maximum current exactly simultaneously. THEY ARE INSTANTANEOUS MACHINES AND REQUIRE MAXIMUM CURRENT IMMEDIATELY FOR A SHORT PULSE THEN STOP, then the start again, and stop etc etc.

I assume they are both set up for the same number of steps per rev or per inch, or millimeter, whatever, so the will perform simultaneously, and (of course) since they are controlled via a parrallel port it will be simultaneous. Even if you can only detect a 1 volt drop on a multimeter, your actual voltage drop will be greater.

Try your power supply running a large motor or something,  and try stalling the spindle and see if the voltage drops when you get to say 10 amps. It must a a big **** power supply to give 7.5 to 10 amps without loosing voltage.

Jim

1166

General Mach Discussion / Re: Mach Turn backlash?

« on: August 08, 2007, 11:36:32 AM »

The backlash works very well in Turn - I have it set up on all my axis - and it is accurate as far as I can see.

1167

General Mach Discussion / Re: More inputs or more outputs, you decide.

« on: August 08, 2007, 11:33:16 AM »

I take it you are designing a USB to parrallel port type of output - or a card to fit in the computer to give x and y numbers or inputs and outputs.

If Mach3 is designed for 6 axis we need two outputs for each (12) then outputs for spindles (2 or 3) spindle speed ? (?) and then coolant (2) - we are on about 17 there - so might as well make it 24 ( 3 x or 32 ( 2 x 16)

Inputs - 3 per axis (18) and I would think another 14 on top of that to bring us up to 32 would suffice.

If the finished card - had 32 inputs and 32 outputs I would have thought you could cater for all of Mach3 requirements.

1168

General Mach Discussion / Re: HELP pleeeeeese Z axis problem !!!!

« on: August 08, 2007, 11:24:14 AM »

RE YOUR Z AXIS - What is it that you are trying to drive. - My Z axis or my milling set up is a very large milling head. As it was it was sprung UP  and I couldn't get the stepper motor to drive it down. Coming the other way it was fine. Yours is probably the opposite way - gravity helps it going down - but works against it going up (although I think you said you had tried a bigger motor).

I ended up gearing my milling head stepper down 5 to 1. I didn't need the speed, but I needed the power to shift this big lump of metal. Bear in mind if the motor is working hard, then the driver board will be working hard - and cut out if it overloads. There is also a warning on my stepper driver notes that if the voltage on the steppers falls below 12 volts, there is a danger the card will over heat - have you checked you driver voltages - you cannot be running them off the 5 volt computer supply.

You have proved (as far as I can see) by swapping the drivers round, that the fault lies on the pysical side of the equation, ie. the mechanics of the Z axis,  not on the electrical (computer) side, so the fault will lie somewhere in this area.

JIm.

1169

General Mach Discussion / Re: loosing steps in one direction

« on: August 08, 2007, 04:31:09 AM »

I do not like spending money until I find out where the problem lies.

I run 220CNm motors on my Warco Lathe. I have Stepmaster drivers. I do not have a breakout board, but run the drivers direct from an old printer cable about 18" long. I got the motors from ArcEuroTrade.
The motors were eight wire that I connected in series to make bi-polar motors. I run them from a 24 volt supply - from large batteries which ensures a steady voltage over a wide current range.

My only difference to your set-up is that the motors are geared down 3 to 1 to drive my axis and therefore I need 6400 steps per rev.
I have tested my set-up quite rigourously for accuracy - I am fortunate because I kept the old 1thou dials on when I converted it, so you can see that the lathe returns to where it started - or you can have a second check on distance travelled. The geared down drive was because I tried using smaller motors - which kept missing steps. With the 220 performance is fine and I upped the gearing to 3 to 1 from 5 to one.

With these settings I have found it impossible to move my axis faster than 4 inches per minute - but I am happy to trade accuracy for speed.

Without getting your ****** in a twist, I think you must be patient and keep trying to find where the loss is. Yes - from what you have said, it would seem that you are loosing steps, but in one direction only.

I cannot think that this will be in the middle of travel, but is probably at the start or finish.

Make up a table with different settings on it. Try a different set of motor speeds and do short - say 1 to 6 inches movement, and check them with digital calipers - in both directions.  Start with slow movement and slow acceleration, and see if you were ever accurate.

Gradually increase the speed of travel, and finally the acceleration.

I left my pulse length at 5  - I tried putting in 10 but it didn't seem to take it.

This may sound a bit complicated - but with a little thought you can do it all in an evening.

I have to be careful with my set up - which works perfectly in the  mid area of my lathe (which, or course, I used to use a lot) but at the extreme ends, I can loose steps, where the lathe (not the steppers) sticks a fraction.

There must be an answer.

Jim





 

1170

General Mach Discussion / Re: estop and limit switches

« on: August 06, 2007, 02:23:22 PM »

I cannot understand your problems, unless you have something really wrong - and I do not think that will be the case.
You do not need a beakout board - this is just a poor mans thinker - but I assume you have identified the wires out of your 25 pin port and you have your limit switches wired to them (each with an appropriate earth or ground). The only problem with some of the pins  is that they are inverted in the computer logic.

I assume you have correctly identified the pins as the appropriate inputs in CONFIG/PORTS AND PINS/INPUT SIGNALS.  If you have all this done, then go to the Diagnostics page and test each limit switch manually with nothing else running. As you close each switch (or in actual fact OPEN it) then the appropriate led should light. If it is already lit, and then goes out, then your active low setting needs reversing in the Ports and Pins page. This should then give the correct signal.  Do check your ground wires, however - because if they come adrift you will get nothing. The ground wires need to be pins 18 to 15 on your 25 pin plug.

Yellow light comes on - E-STOP

Have a look at the instructional video which explains all this in some detail - and how to combine limit switches with home switches.