Topics

41

VB and the development of wizards / speed of execution of macro

« on: December 24, 2010, 11:40:31 AM »

Hi,

As part of what I'm doing, it looks like I need to write a macro that I will call from Gcode quite often. maybe 40 times a second... ie one call on each line.

My question is, how long (in microseconds I guess) does it take to call, execute and exit from a macro? The macro will only be about 5 lines long.

Any ideas?

Thanks, Richard B

42

General Mach Discussion / thc in macropump

« on: September 27, 2010, 12:46:07 PM »

Hi,

I'm using my Z axis to drive a dispensing pump (as in my previous posts.) The pump's pressure (ie whether the Z axis advances or not) will be regulated by a logic on/off signal from a strain gauge/amp/comparator circuit. The circuit appears to work fine as a spice model, parts are on order for the circuit itself, so all's well there, barring signal to noise ratio problems.

I'm hoping to run a macropump to control this using DTHC. So the macro will keep the dispensing pump at optimum pressure whenever mach is running, by doing a 'THC down' whenever the pressure drops off a bit.

Trouble is, beyond defining this as rather fluffy pseudocode, I'm unclear about what the code might look like. I don't want to confuse myself further by looking at the wrong macros for inspiration.

Can anyone suggest a bit of code that already exists that might do some/all of what I need? My code understanding is not fantastic, but hopefully I could see how it works. Then me/my friend who enjoys programming/ can put something together that does the job!

Thanks,

Richard B

43

General Mach Discussion / call macro from another macro

« on: September 27, 2010, 12:14:49 PM »

Hi,

I'm guessing this is possible; can I call a macro from inside another macro, maybe via some conditional statement or other? Something along the lines of "If A=0 then M06"?

Thanks, Richard B

44

General Mach Discussion / F for feedrate

« on: September 04, 2010, 01:56:49 PM »

Hi,

Confused: F commands; do they set an overall tool feedrate which is interpolated from the velocities of all axes, or can each axis have it's own F value applied to it? Somebody asked me earlier and I realised I didn't know.

Rich B

45

General Mach Discussion / max lines of code

« on: August 28, 2010, 05:22:31 PM »

Hi,

This may be in the documentation, but in case it isn't,how many lines of code can Mach3 handle in 1 file?

Rich B

46

General Mach Discussion / twinned motors; 2 sharing 1 driver

« on: August 07, 2010, 05:47:43 PM »

Hi,

I'm wondering what the problems are with wiring 2 steppers into 1 driver, and just doubling the current? I intend using a motor at either end of a long bike chain; the chain will hang very slack, and the 2nd motor is just there to stop one side of the chain clashing into the other.

The application for this is a revolving 'carousel' pen holder for a large plotter.

Only got 1 axis left in Mach, but 2 motors left in the box! It's tempting to try it, but there must be a reason nobody does it that way.

Rich B

47

General Mach Discussion / z axis driven pump: pressure regulation /logic input question

« on: July 24, 2010, 10:08:55 AM »

Hi,

I have a plotter that uses incremental movement of the 'z' axis to drive a material deposition pump. (Another axis (A) causes a small piston to oscillate and print the material onto a flat surface.) I had originally wanted to use the spindle drive for driving the pump, but my ncPod controller does not do spindle control, apparently.

There is a slight problem with pressure regulation, which I intend to solve by fitting a load cell, with circuitry to generate a logic 1 when the pressure falls below a predetermined value, and logic 0 when pressure is satisfactory. I hope to use the logic 1 signal to start the pump (ie cause the z axis to step), and logic 0 to shut it off again, thereby achieving pressure regulation.

Is there a way in Mach 3 to start/stop an individual axis in response to a logic input? It might be a bit like giving an Estop signal to just the one axis.

Does anyone know if Mach can do this? Or should I think about putting an Arduino on the machine to control the z axis seperately to Mach 3? Bear in mind that the z axis s not being used to position anything, just to provide pump presssure. The actual printing is done by the A axis, which must remain under mach control.

Any ideas?

Rich

48

General Mach Discussion / speed control of stepper used as spindle motor

« on: April 22, 2010, 03:47:27 PM »

Hi, I've asked this before in a different (maybe over complicated) way and got no replies, so I'm rephrasing it to get to the point a bit more...

How exactly does Mach3 handle step/dir for a stepper motor used as a spindle?

Under say, an M03 command, does it produce a step signal and direction signal, and have some internal algorithm for changing the frequency of the steps to alter the spindle speed? I assume this would need to be sent through a driver as for any ordinary axis.

Is it just a matter of connecting up a stepper motor as if it were an ordinary axis, but specifying it as 'spindle' in the motor outputs panel? still not sure why I can't make this work

Richard B

49

General Mach Discussion / pins 4 and 8 on ncPod to drive spindle step/dir?

« on: April 15, 2010, 06:53:21 PM »

Hi,

I have a 2d plotter running mach 3 with an ncPod. X and Y axes are pins 2,6 and 3,7 respectively in 'Ports and Pins', and 'pen up/pen down' is provided by the A axis. Originally I was using the Z axis (pins 4,8) to test drive the material deposition pump/pen thing (linear stepper), but decided to control this using the Spindle Speed Step/Dir option instead. So I disabled the Z axis, enabled 'Spindle', and gave it ports 4 and 8 (from the Z axis) so I wouldn't have to change any wiring.

Under the 'Spindle Speed' tab, all is default, except that 'Use Spindle Motor Control" and 'Step/Dir Motor' are checked, 'PWM Control' unchecked. Also. as I don't need delay for a pump, the 'Delay Spin' times are all set to zero; not that I'm sure I understand that this is what it's about anyway.

On entering 'G01 F10 X-5 Y-2 M03' in the midi screen, the X command executes, the Y doesn't (which is very odd), and the light above 'Spindle CW F5' lights yellow, but the pump doesn't respond. Following this with a reset, then 'G01 F10 Y-2 M03' gets the response 'Unknown word where unary operation could be'.

I'm guessing this is a pin number issue, but I don't know if I should be using the 'Output Signals' ports and pin dialogue boxes somehow. Confused, been a long day... This is the information from the ncPod manual:-

Output            Mach Pin #

PWM Gnd        NA      Just enable in Mach
C      Gnd        ***
E      Gnd        1
B      Gnd        3
D      Gnd        2
F      Gnd        4

It says under that:

-'You can select any output/enable you like in the “Ports and Pins”, “Output Signals” menu and set the “Port#” to 1
with the “Pin Number” matching the output you wish to use. For example; if I want to use “F” as output # 3, from the
main menu in Mach I would select “Config”, “Ports and Pins”, “Outputs” tab and check “Output #3. For the “Port#”
setting I would enter “1” and for the “Pin Number” enter “4”.'

I probably have all the information here to sort this out, but can't make head or tail of it at the moment.

Anyone willing to point this out to me?

Thanks,

Richard B

50

General Mach Discussion / .obj file to g code

« on: April 03, 2010, 01:42:23 PM »

Hi,

I'm new here, and a bit confused about something...

What are my options for converting a mesh model made in Wings3d (a subdivision modelling program) into G-code to send to my 3 axis mill? (When it's complete, that is.) Wings can export in a number of file types, including .obj, which is a wavefront file, I believe. Does it then need to be converted to a parametric solid? If so, what software is good for this?

The general idea is use a 3d scanner (David 3d or Nextengine if one comes up at the right price) to create mesh files to edit in Wings, then output to the mill,  machine up and use.

I hope no-one minds me asking this here, I know it's a CAD question rather than a CAM question, but as it all ends up as G-code, it seemed like a good place to post this.

Thanks all,
Richard B