Topics

11

General Mach Discussion / Mach torch height control vs full external Z control

« on: April 27, 2015, 05:37:03 AM »

I'm on the design path again, this time to build a plasma torch height controller for Mach.

I'm going to start with letting Mach do the Z movements so my THC will simply monitor the torch volts and send the up/down signals to Machs input pins.

I've heard a certain manufacturer of a THC say Machs built in THC was too slow (?? no more details). His model fully controls the Z motor, leaving Mach to just do the XY moves during the cut.

Does anyone have any actual experience with one verses the other. What shortcomings would a THC have when it used Mach to do the Z moves. Has anyone came across this way being too slow as just mentioned.

I know Machs THC does not have acceleration / deceleration on the Z moves, and this can limit the speed at which a stepper can operate. Try to make a stepper go a certain speed instantaniously and it stalls / loses steps. Would the closed loop of a servo motor help in this regard because it can catch up to the steps commanded.

Cheers,

Keith.

12

General Mach Discussion / Mach3 Driver Test - no line & zero pulses per second

« on: July 30, 2013, 07:20:27 AM »

I've installed Mach 3 on quite a few computers but this problem is a first for me.

XP installed in Standard PC mode
Go through XP optimisation
Motherboard drivers installed
Install Mach3 and reboot
Run driver test - no line, and zero pulses per second, even though says system under Mach3 control

Tried ECC+EPP, and EPP settings for parallel port in the bios.

Uninstalled and re-installed Mach (including uninstalling pulsing engine from Device Manager) but same results.

I'm stumped, anyone got any ideas or should I toss the computer.

Processor is a 3Ghz P4, 2MB cache, 800 FSB and have 1G ram PC3200

13

General Mach Discussion / G28.1 with feedrate added into the mix

« on: May 08, 2013, 05:18:07 AM »

My cam software for my plasma cutter gives me the following code as part of the touch of sequence:

G28.1  Z15  F500

From safe Z my torch rapids down to 15 mm then travels to the home switch at a reduced feedrate. What I am not sure of is whether it will be using the F500 code or it will be using the % speed setting in Config/Homing Limits. I assumed having the F500 in the line of code would OVERIDE the % setting in Config/Homing Limits.

Someone has told me that in the code above the F500 is redundant because it only comes into play IF there is a G1, G2 or G3 in the line of code. IS THIS TRUE ?? That's my big question.

Googling Mach & G28.1 a description of G28.1 was that it causes a homing move at a % (set in Config/Homing Limits) of the CURRENT feedrate. If that's true then doesn't that mean the homing speed will change depending on what the current feedrate is. I always though the homing % speed setting was a percent of rapid speed and would always be the same.

I'm hoping the F500 command in the line of code will overide the % setting so my homing speed is consistent regardless of the current feedrate.

Cheers,

Keith.

14

General Mach Discussion / Un-install & re-install changes Mach3

« on: August 01, 2012, 01:01:57 AM »

Hi All,

I'm messing with 2 versions of Mach3 - 3.42.020 & 3.042.029

A plasma cutting plugin is installed once Mach has been installed. For certain reasons I've been un-installing Mach / plugin then re-installing to the other version of Mach.

I noticed the THC (torch height control) button was not working. This is a toggle button with an LED to go with it. I checked on another computer which had recently had the very first install of Mach and the THC button worked fine. I un-installed Mach on this computer then re-installed and the THC button did not work any more. So I've managed to repeat this problem on two independant computers.

It seems the un-install and re-install of Mach3 is corrupting something. I am now going to format the drive on my workshop computer and re-install XP. If this issue is repeatable then in my case an un-install of Mach3 means a re-install of XP just for Mach to install correctly.

Another point of note is that when I re-installed Mach3 (no plugin install yet) I opened the plasma profile and the THC button would not work (just in case the plugin is being blamed).

Anyone got any ideas ??

Cheers,

Keith.

15

VB and the development of wizards / What variable number do I choose

« on: July 08, 2012, 10:38:52 PM »

Hi Everyone,

I'm just getting into screen design, VB macros, etc. I'm managing to get some grip on the code in macros written by others, but one thing I can't find info on is the variables numbers used in the VB code.

Example:
SetVar(601,Getdro(2))      'Set variable to Z position

Why did the author choose the number 601 for this variable.

Is there any info, or a list of variables that are used in Mach3 (a question I've noticed others have asked in the past and don't seem to have got a straight answer to).

I've read there's over 10,000 variables in Mach but have no idea if some are "special / reserved / used" for certain purposes, and if others are general use for anything.

Can anyone enlighten me please.

Thanks,

Keith.

16

General Mach Discussion / Driver test does nothing - no test line

« on: May 22, 2011, 07:40:16 PM »

Bought three PCs and am onto my 2nd one formatting hard drive, installing XP in Standard PC Mode, optimising XP, etc.

First computer everything installed great and ran Mach driver test at 100 khz and great.

2nd computer - all install files are the same but this time the Mach driver test does nothing. Well it goes through the initialisation then finally says system is under Mach control but there is no test line in the graph area.

Readings are:
CPU Mhz:            3001
Shortest time      33674.794
Longest time       33674.794
Apic Timing Constant       50
Interrupt Used     0
Max variation        0
Average Int         33674.794
Longest Int         0

I re-installed mach after uninstalling the parallel port driver in Device Manager but get the same results.

Installed Machs Special Driver and the driver test seems to work except instead of a straight line I get a black block up to where the line should be and this black block has evenly spaced spikes coming from the top and the bottom.

So far I,ve had only one PC out of four where everything has installed and worked without any issues. Seems to be an element of luck involved with what pc works and which one doesn't.

17

General Mach Discussion / Can a slaved axis have different steps/mm in motor tuning

« on: January 13, 2011, 05:39:56 AM »

Hi All,

Let's say you have any sort of cnc table with one of the axis dual drive. Just for arguments sake lets say it was a gear rack on each side and due to terrible manufacturing one gear rack was a few mm longer than the other (please don't get caught up in the aforementioned sentence, it is just hypothetical and the next paragraph is the question I'm trying to find an answer for). To compensate for this you'd need to have different steps/mm for the master and slave motors. Now here's my question.

In the Mach manual it says that a slaved axis recieves the same steps pulses as the master (under normal conditions !?). Is it possible for a slaved axis to have different steps/mm as the master axis. This of course would mean that the slaved axis could not get exactly the same pulses as the master. Rather the slave would recieve the correct number of pulses to move it the same distance as the master.

A member on Cnczone said he tried programming different steps/mm in his slaved axis but Mach ignored it and sent the same pulses as the master. Anyone know of any workarounds for this one.

What is meant in the Mach manual when it says "under normal conditions". Does this imply there are non-normal conditions where they don't get equal steps.

Thanks,

Keith.

18

General Mach Discussion / Rogue step pulses when system idle

« on: January 13, 2011, 05:18:50 AM »

Hi Everyone,

Built a plasma cutting table, using Mach3, MP3000 from Candcnc with associated Mach plugin, Gecko G203V drives for the stepper motors.

I have a rather strange problem which I believe is not caused by Mach or its MP3000 plugin. Lots of people with this system and never heard of this problem. The MP3000 has opto-isolation, buffering, etc. 

Mach is online (not in reset), but is idle (no gcode running) and when I click various tabs and buttons in Mach can hear one of my stepper motors nudge. It's exaclty when I do the clicks on screen items.

However, I also discovered when I was just standing there that these rogue step pulses also happened without me clicking on the screen. I looked close up at my gantry stepper and could see the shaft turn ever so slightly when I heard the dreaded nudge. Roughly every 10 seconds.

Doesn't happen when I put Mach in reset but I've been told the MP3000 pulls up all its outputs when Mach is in reset.

So I'm guessing I've got some driver / service / program in XP causing this or it's just some hardware problem.

All in one motherboard MSI G31M3 V2, socket LGA775 , P4 3.2 Ghz, built in parallel and serial ports, (tried an independant graphics card and set this in the bios as primary graphics adapter but problem remains). Have a 2nd parallel port installed in one of the PCI slots, unused and just sitting there if I ever need it.

Mach driver test always seems to be excellent at 100 khz

Formatted hard disk, installed XP in standard PC mode, did the recommended XP optimisation for running with Mach. No other programs besides Mach3 and the MP3000 plugin.

Any suggested process of elimination, bios settings, disabling drivers, services, processes, etc. What about trying the PCI parallel port instead.

Does anyone think this is a hardware issue and maybe I'd be better off changing the motherboard out.

I'm guessing a few people will say noise but the fact it happens exactly the instant I do mouse clicks rules that out a bit, would you agree.

Thanks,

Keith.

19

General Mach Discussion / Steppers sent steps when changing screens

« on: September 24, 2010, 12:02:36 AM »

 
Hi All,

wondering if anybody has experienced this one.

Testing the X and Y axis of my almost finished plasma table. Everything seems to be working fine apart from some steps (always negative) being sent to both axis when I do things like swapping between different screens in Mach or using the tab key to open the jogging window. Mach is not in reset (i.e. reset button is green and not flashing) but the program is not running. This is how I first picked up on it, I could actually hear the motors nudge a tiny bit while everything was still.

The computer is bare bones nothing but Mach installed. Windows XP installed in Standard PC mode. Done the recommended optimisation, killing startup items, etc. I can do a 30 minute program run with the X and Y axis "cutting" a zillion little pieces and the machine arrives back at zero point exactly. Yet simply changing between screens with no program running causes negative steps to be sent to both axis. The digital readouts do not change so every few negative steps sent gets the axis more out of position.

Thanks,

Keith.

20

G-Code, CAD, and CAM discussions / What purpose does this gcode serve

« on: September 18, 2010, 07:25:07 AM »

Hi All,

I'm learning the gcode which is output from Sheetcam for my plasma cutting table. I have a touch off Z-axis for referencing the torch height to the top of the material before each cut. I'm using the "MP3000-DTHC-SmlArcFix" post processor which is written for Mach.

Here's the first few lines of the gcode:

N0030 G21 (Units: Metric)
N0040 G53 G90 G40
N0050 F1
N0060 (Part: Sheetcam Tryout - Square)
N0070 (Process: Outside Offset, VISIBLE, T1: Plasma, 2 mm kerf)
N0080 M06 T1 F2000 (Plasma, 2 mm kerf)
N0090 G00 Z12.7000
N0100 X857.4000 Y942.6000
N0110 G28.1 Z12.70
N0120 G92 Z0.0
N0130 G00 Z0.1370
N0140 G92 Z0.0
N0150 G00 Z5.0000
N0160 M03

Questions:

Why is F1 (1mm per minute ?) inserted in line N0050. It's correctly set at 2000 mm/min three lines later.

What is the meaning of having a tool change on line N0080. I'm a beginner to this but I can't see any purpose to this, I mean there is no tool change. I would have expected just the feed rate to be set and that's it.

Line N0090 says rapid the Z-axis to 12.7 but at this point the Z-axis position is not known, it hasn't been referenced / homed. With a floating Z-axis on a plasma cutter the homing is the touch-off and is the top of the material, and this is not done until after this starting on line N0110.

I think I've got the rest of the gcode worked out but the above has me stumped at present.

Thanks,

Keith