Messages

971

General Mach Discussion / Re: Everything I learned about setting up a 4th axis & a question/problem

« on: December 28, 2007, 01:57:41 PM »

Ive got the picture now - rather like writing (only in this instance cutting) the Heinz logo on a can of beans. The A axis rotates the can backwards and forwards and the other axis goes up and down. The other axis - holding the brush - is fixed.

I must admit, then, in that case, if you have correctly set your pulses per distance, I cannot see why it cannot perform G2 and G3 as well. The only thing I can see is if the A axis still knows it is a rotating axis and not linear. In that instance, it could perform linear movement but still not reference itself to the centre of a circle.

A silly thing - looking at General Config - have you ticked A axis as angular. I know it is, but we are making believe it isn't, therefore the machine must think it isn't. I dont think it would make any difference to G0 and G1 moves, but an angular axis cannot make G2 and G3 moves because it cannot reference a centre with another axis.

972

General Mach Discussion / Re: Estop at wrong times web cam how do i ? help

« on: December 28, 2007, 10:34:54 AM »

Bill - sorry to jump into the post -

Brett - yes, got that, I might try and get hold of Zarzul and get him to e-mail the drivers

Thanks.

973

General Mach Discussion / Re: Z axis setup problem

« on: December 28, 2007, 10:27:52 AM »

before you do that, swap the step and dir leads from your x axis driver to your z axis driver. Does the fault move as well, or does it stay with the Z axis. Then jog the Z axis, using the X axis jogger and vica versa

If the fault moves, the fault is with your Z driver card not seeing the dir signal. If the fault does not move then the fault lies between your computer (which you say you have checked) and the breakout board.

974

General Mach Discussion / Re: Trouble with Mach Quit Running

« on: December 28, 2007, 10:10:22 AM »

Did it quit at the same place each time

I know my very small programs (by that standard) are checked by the computer before they run and any faults are highlighted. I wondered if this was doing the same, but checking the program in batches - and cutting out when it found a fault.

975

General Mach Discussion / Re: testing a reflective object sensor??

« on: December 28, 2007, 09:05:06 AM »

Tony - Yes- I have done it again - a very rough voltage for voltage calculation gives 3K and a more complcated one gives 1k140. If I were to use 12 volt supply I would try 3k and work down until I got optimum performance. It seems to indicate in the spec that the voltage drop over the diode can be up to 1.7 volts - ANYBODY ELSE LIKE A GO.

I don't think it is relevant, however, because there is a 5 volt supply available on the card. Use the resistor shown, which I know works because thats what I used.

976

General Mach Discussion / Re: Spindle Speed setup

« on: December 28, 2007, 08:55:17 AM »

Tony - thanks for that - because the board is on it's way from Australia !!!

I will have another read of the Mach3 set up manual when it comes.

977

General Mach Discussion / Re: Implementation of Logical IF Then Statements

« on: December 28, 2007, 08:50:00 AM »

Dan - the way I have approached this is to write VisualBasic programs. There is a Visual Basic editor in Mach 3.

I write these macros and give them M numbers - M201, M202 etc etc. Visual Basic is a straightforward computer language and If, While, For etc can all be used. My macros include one to thin down a piece of stock to a required diameter over a given length at a desired depth of cut, and one to round the end of a bar to a given radius.

I have included additional DRO's on page one of Mach3 Turn, and I can fill in the various dimensions I require.

All I do is move the cutting tool to a known start point, call up the Macro and away it goes. Macros can be included in ordinary G Code programs as well. They work on a system of calculating the moves required, then writing the code to the computer on the fly, so the only code you see in the program is e.g. M202.

There is a video tutorial on Vis Basic in the collection.

Jim

978

General Mach Discussion / Re: Everything I learned about setting up a 4th axis & a question/problem

« on: December 28, 2007, 08:28:45 AM »

If I am getting the point of the post - what we are saying is this complicated way of converting angular motion into linear motion seems to work alright if we stick to simple straight line formula. Once we ask the computer to move the axis in a circular motion then it goes bananas.

If you think about g2 or g3 moves, these ask the computer to guide the axis around a plane in a circle. Since the plane is flat, then the distance from the centre of the circle can be easily calculated, and the vectors of the points on the circumference of the circle (two co-ordinates) can be calculated as the tool advances. As we probably know, one axis advances as per a sine wave, the other in a 90 opposition.

What you are trying to do is the equivelant of drawing a circle on the side of a sphere. You cannot represent the centres of a flat circle and a circle of the same diameter on a sphere by the same point. If you imagine drawing a circle the same size as the sphere, then a flat representation would show the diameter as D, whereas the true diameter of the circle you actually wanted to draw is pi D/2. The same is true if you imagine drawing a circle on the side of a cylinder, but only on one axis.

Your method may work - but it is not based on the actual mathmatics involved. Whilst angular mathematics is complicated it is easier working in degrees or radians where appropriate - particularly if you are going to mix flat planes (essentially two co-ordinates) with spherical or spacial measurements (essentially three co-ordinates).

979

General Mach Discussion / Re: Spindle Speed setup

« on: December 28, 2007, 06:06:14 AM »

I am interested in this subject because I have just purchased a board to convert the PWM signal to a 0 - 10 v signal to regulate my Omron inverter (the spindle motor driver). I already have feedback from the spindle to the computer for r.p.m. measurement.

Are we saying there are difficulties in marrying the two together, to get true automatic speed regulation of the spindle ?

980

General Mach Discussion / Re: testing a reflective object sensor??

« on: December 28, 2007, 05:46:37 AM »

Further to the above (having Googled Bob Cambell designs ) the breakout board also provides a 5 volt power supply. It says this is for the optical isolators on the Geeko drives. Why not use this - the sensor you are using is only a form of optical isolator - the isolator is a package that generates a signal and shines it across to a reciever - you are generating a signal and shining it to a reciever (albeit via a mirror) they are identical - use the 5 volt supply on the board.

I would have to have a look at Campbells circuit diagram to understand where you have to put the input. Can you wire direct to the computer pins. The input he has provided with the 0 - 12v supply is for proximity devices and it then says the signal is converted back to 5 volts. You don't want that input - you are already at 5 volts ( in fact your device is not at any voltage if you remove the pull up resistor. All it does when the signal shines on it is ground the signal wire (0v)). See if there is a pin on the breakout board to put the signal directly to the computer (pins 10 - 13, 15). Test the input pins, they should be at 5v (i.e. they have pull up resistors). If on Campbells board the inputs are a bit indeterminate, then you may have to include the pull up resistor as per the original circuit.

I hope this is not too much waffle