Messages

51

General Mach Discussion / Re: X Y axis is opposite

« on: May 17, 2009, 02:38:17 AM »

Jessey - You can change the "short cut keys" in the config menu - look under "Config/System hotkeys" and you can allocate any key to any function quite easily.

Although it might not be the done thing, you need a system you are comfortable with, and you need to look at your table, and your fingers automatically go to the keys you feel comfortable with to produce the moovement you want.

That may sound gibberish, - but -

What I mean is convention says you should allocate the keys the way the "cutting head" moves - but if you feel better allocating them the way the table moves, then do so.

I have a combined lathe and miller - so to avoid confusion, I have one system of hotkeys, whether I am turning or milling - so my brain does not have to remember what "mode" I am in.

52

General Mach Discussion / Re: noob - help on breakout card and parallel port card

« on: May 17, 2009, 02:26:13 AM »

The 25 pin LPT1 port is actually three ports in one.

The main data port is 2,3,4,5,6,7,8,9 at address &H378. The input side of the port is pins 10,11,12,13 and 15 at address &H379 and the four secondary outputs are pins 1,14,16 and 17. Pins 18 to 25 are signal return wires. A bit of a mismash.

You should be able to use any outputs with any other, but depending how your CNC4PC breakout board is wired internally, you are better to use (as you have done) pins 2,3 - 4,5 and 6,7 as the axis outputs. Make sure, however, that each section of the board has a signal return wire connected (if required)

You will eventually require - outputs for your spindle motor, and your limit/home switches, and will soon come up against a shortage of pins. I do not bother with the charge pump - it is easier to turn the computer on, and when I have Mach up and running, then turn on the supply to the lathe electronics. Neither do I bother with the enable wires to the various axis - I can't see why you need them. If you are using the machine, they would be on anyway.

The only exception is I have an enable to my milling head because I have a combined lathe and mill - but that is a manual switch and does not use up input pins.

The way to test your outputs reliably is to go to Ports and Pins/Spindle set up and untick "disable spindle relays". Set the output for M3 to #1 and the output for M4 to #2. If you now go to  Ports and Pins/Output signals then you will see you can allocate Output #1 or #2 to any pin you wish.

The M3 (#1) will output if M3 is written in the MD1 (or if the spindle start button is pressed) and #2 will output if M4 is written in the MDI line (M5 cancels both outputs) By allocating these two outputs in turn you can test each output pin on your CNC4PC board with a volt meter. I think the CNC4PC board inverts the signals, so an output may appear as a zero (when on) and 5v when off. You can reverse that by ticking active low on the Ports and Pins page.

The other thing I seem to remember is that the CNC4PC board also had different common return wires that could be wired with the various sets on inputs/outputs. This makes it difficult to set up, becasue it tries to be all things to all people.

You should, however, using the method above be able to trace the signal from the computer, along to the "input" side of the breakout board (this should be a +5 volt signal. You should then be able to trace it through the board to the output side (where it could be a 0v signal).

The inputs and outputs of all the pins are shown on the diagnostic page of Mach 3 to start you off - if it appears there it is, at least getting out of the computer.















 

53

General Mach Discussion / Re: Dwell after M05 (torch off)

« on: May 16, 2009, 03:59:36 AM »

I have never looked at the plasma cutting screen, but it would seem to me that the "torch off" command could be altered. I don't know how you arrive at M5 for this - is it a standard instruction (it is used for spindle off on a lathe/mill).

If it is standard, then open the M5 macro, and add the movement to beginning of the macro -

eg  code "G00 Z50".

This will mean that everytime the M5 macro is called, the script will first move the Z to 50 (or anywhere else you want it to go), then apply the "torch off" OEM

The fact that sheet cam puts in the G00 Z50 again won't matter, because the torch will already be there.

54

General Mach Discussion / Re: Problem just appeared with G91/G41 combination

« on: May 16, 2009, 03:44:44 AM »

Second try -

When applying tool offsets, there must be some lead in from the line applying the offset, to the next cutting line, so the tool can move to the correct position (left or ringt of the design line)

On your G90 code, this will be allowed (although I don't think it would be fully applied on the first G1 after the G41.

On the G91 code, G91 moves in increments fronm a previous position, and therefore Mach would take the last known position from the DRO's and apply the increments to them. You have no tool movement between applying G41 and G91 therefore the G91 will take its start position from the DRO's as they were after the X0Y3.594.  

55

General Mach Discussion / Re: question from beginner

« on: May 15, 2009, 03:10:32 AM »

Just check which units you have set set up in, and which units you are runing in.

Check you GCode program for the F command, and see what speed you are expecting.

If you have got as far as running GCode, we must assume that you have set the machine up correctly i.e. your steps per unit etc are correct.
Go to motor tuning, and see what maximum speed you have set. I don't know what your machine is, or what speeds you are expecting, but the way to tune the motors is to start with a low figure and gradually up the spedd. Check this by jogging your axis. You will reach a point where the motor breaks down. Back the speed off until it resumes again ( and perhaps a little more for reliability ) and your maximum speed is set. Do the same now with the acceleration. Ensure that you SAVE each axis as you do this, or your machine will revert to the last setting as soon as you leave the page.

Have you set up in mm, and your cad/cam is writing a program in inches.In this case, you must ensure that there is a G20 (imperial) command at the beginning of the program - otherwise your machine will take all its movement in mm rather than inches - and move 25 times too slowly.

As Hood said, you must Calculate your steps per unit.for your axis. Most (stepper) motors are 200 steps per rev.Most drivers operate on micro steps, 8 or 10 perhaps - that is 2000 steps and if your leadscrew is, say, 10 turns per inch then this would be 20,000 steps per inch, If you have any step down gearing ( I have 3 to 1 on my steel lathe) then that puts the steps per unit up to 60,000 per inch. I have recently gone metric (with ball screws) with a 5mm pitch thread, so my steps (now per mm) are down to 1,200 per mm. This is the order of scale you should be looking at.

56

General Mach Discussion / Re: Problem just appeared with G91/G41 combination

« on: May 14, 2009, 12:54:40 PM »

Have you got the XY plane active - if you read the notes attached to the GCode explanation on Mach 3, it says the D command will not work unless the XY plane is active (G17).

G17 should be included in the prelim of your program

57

General Mach Discussion / Re: very simple manual tool change question

« on: May 14, 2009, 12:43:06 PM »

You need to change the settings in Mach to "Auto tool changer"
This means that when Mach comes across an M6 command it follows a program written for it  in Macro M6 which as a default is just written as "get the selected tool - this is the tool" in other words it doesn't do anything.

The Macro M6 can be change. It is a visual basic program which you can write, to move the tool to a convenient position (usually expressed in absolute co-ordinates - to avoid difficulties with offsets) and then stop there until you change the tool - an M1 command. You can change the tool and press cycle start, and program the tool to return where it was, on move the tool (jog) to a new start position, before you press the Cycle Start.

The is an explanatory video about scripting, which specifically deals with tool changing.

58

General Mach Discussion / Re: Turn G3 feedrate problem

« on: May 10, 2009, 03:04:49 AM »

Is this anything to do with it -

If the axis continue to travel at their same speed, the compund "feedrate" will be faster (Pi D). I don't know how the maths is done to get the "circle" but it may be that one axis keeps a constant speed and the other then adjusts speeds to give the circle. The alogrithim on the two axis in a straight line would appear to be that the axis moving further gives the initial speed and the other axis adjusts it's speed appropriatly. It may be that this also applies to the "circle", but the compund speed would be greater.

59

General Mach Discussion / Re: Need script help

« on: May 03, 2009, 11:25:00 AM »

What happens on the real machine if you just ignore the "stop".  Say use an M1 instruction, then just rewind.

The problem with "stop" is that it is designed to be just that - STOP - and it literally slams the brakes on everything to avoid damage to anything. I would try and rewrite it without using a stop. Perhaps M30 has the same effect - that is end of code and rewind as far as I can remember.

60

General Mach Discussion / Re: Need script help

« on: April 30, 2009, 02:33:13 PM »

This caused me a bit of grief, but I think I have worked it out - although I can't quite envisage how you want to use it.

Have you got all this code on a single button?

If so, then when you press "pause" the machine jumps from the GCode program to your VB program (on the button) after it has finished the line that is executing. So it makes the jump. The axis have stopped moving therefore the While/Wend is satisfied, and it moves straight to the Stop.

I still can't understand the logic of what you are trying to do, however, can you expand a bit - while do you need to pause before stopping