Topics

81

Brains Development / Stuck on brain

« on: November 26, 2010, 10:54:52 AM »

I know I can turn things on and off based on conditional logic, but what I need to do is set a userDRO = to an OEMDRO if OEMLED(36) or torch lit input is active.  In an if statement it would look like this...

If "Torch Lit" then
   USERDRO(2000) = XPOSITION
End If


Another possible way to do this would instead of continously updating the USERDRO(2000), just set it to XPOSITION the moment "Torch Lit" is lost.

In the brain editor I see an input for "torch lit" and I see the DRO's, just not sure how to connect them all in a brain.   

TIA

82

General Mach Discussion / Unit of measurement for accelleration

« on: November 21, 2010, 11:51:20 AM »

On motor tuning when you set acceleration of say 50, what unit of measurement is that?  I think it's ??/sec, but I can't remember.

Thanks

83

General Mach Discussion / Homing slaved axis with a common switch

« on: November 07, 2010, 01:17:49 AM »

My current setup consists on a gantry with both sides driven through a drive shaft with one motor.  There are limit/home switches on all three axes.  They are all NC switches and connected in series.  Homing and limit functions work well and as expected.  I'm thinking about losing the drive shaft and going to 2 motors, so I'll have A slaved to X.  Ideally, I'd want to just add another switch to the A side of the gantry and wire it in series with all the others.  Will this work properly for homing the slaved axis or are two independent home switches needed?  What I'm after is for the gantry to square when it is homed.

One problem I can see is if X and A are homed together and the gantry is close to square,  X could hit first then A could hit before X has had a chance to back off it's switch... Or would A stop when the X switch makes contact, wait for X to back off then continue?  I'm low on inputs, so trying to figure out if this will work before making any machine changes...and trying to avoid the low tech method of squaring (Turning off machine and pushing the gantry against hard stops.)

Thanks


 

84

General Mach Discussion / Load G-code program externally

« on: November 04, 2010, 10:54:50 PM »

Hi All...

Is there a way to load a g-code program from another program.  I have an app written in VB.net that writes g-code to a file.  I'd like to have that file load automatically into mach after it is generated.  Is there a way to do this without using the Mach API? 

Thanks

85

General Mach Discussion / Hesitation at intersections

« on: October 31, 2010, 12:07:47 PM »

I wasn't quite sure how to describe this.  I'm getting a hesitation similar to what you would see in exact stop mode at the transition between lines and arcs.  Seems to be just were the trailing end of a line segment meets the leading end of an arc.  On intricate cuts where there are lots of line and arc segments back to back, it acts almost as if it's in exact stop mode.  Seems to be just on line/arc transitions.  Arcs are smooth and a chain of line segments are smooth.  See the image.  red arrows indicate where there is hesitation.  CV is on and none of the CV Mode boxes are checked.  Velocity is set at 500IPM and acceleration is fairly low at 25.  This seems to get worse at higher speeds, but we're typically cutting at anywhere between 80 and 200IPM and we see this a lot at those speeds.

Here is the code.

N0060 M03
N0070 G04 P.5
N0080 G01 Z0.1250 F30
N0090 G02 X-0.03Y0.25I0.0000 J0.25 F90
N0100 G01 X-0.03 Y1.75 F90
N0110 G02 X0.25 Y2.03 I0.28J0.0000 F90  (Hesitation Here)
N0120 G01 X1.75 F90
N0130 G02 X2.03 Y1.75 I0.0000 J-0.28 F90 (Hesitation Here)
N0140 G01 X2.03 Y0.25 F90
N0150 G02 X1.75 Y-0.03 I-0.28 J0.0000 F90 (Hesitation Here)
N0160 G01 X0.25 F90
N0170 M05

Thanks in advance...

86

General Mach Discussion / Is this possible?

« on: October 17, 2010, 08:02:18 PM »

Is it possible to change a pin assignment via VB?  for instance, change the probe input for pin 11 to pin 12 using a VB script.

Thanks

87

General Mach Discussion / Relationship between acceleration and CV.

« on: October 11, 2010, 08:58:52 AM »

Hi All...

I was wondering if someone could set me straight on this.  I'm having some trouble getting arcs to cut smooth.  For conversation sake, lets say we have two kinds of arcs.  (1) consistent radius arcs where you have one arc with a consistent radius from start to finish and (2) variable radius arcs where the arc is made up of small line or arc segments.  Variable radius arcs are causing the problem.

This is on a plasma machine and speed is set to 500IPM with an acceleration of 40.  Steps per inch are 1712. on X and Y.  Yesterday I was cutting a file with lots of variable radius arcs from 1/8" steel at 230IPM and noticed that I had a lot of jerky motion in the arcs.  The longer consistent radius arcs were smooth and cut at full speed, but the variable radius arcs were jerky and cut much slower.  CV is on and none of the CV helpers are checked in general config.  It seems that this is amplified the higher the acceleration is, almost as if the higher acceleration begins to override CV where it begins to act as if it's in exact stop mode, especially at higher speeds.   I can reduce acceleration where arcs are smoother, but then at higher speeds corner rounding is excessive.  To reduce corner rounding I have to lower the speeds.  It also appears that I can reduce speed and arcs get better.  The issue seems to be high speeds AND high acceleration.

Here is little chunk of code from one of these variable radius arcs.  This is just a sweeping curve and uses a bunch of small arc commands to complete the curve.

N0710 G03 X6.6918 Y7.5278 I0.1871 J-0.0141 F170.0
N0720 X6.6919 Y7.5145 I0.2151 J-0.0051
N0730 X6.6928 Y7.5007 I0.2417 J0.0092
N0740 X6.6945 Y7.4866 I0.2618 J0.0250
N0750 X6.7043 Y7.4444 I0.2762 J0.0415
N0760 X6.7089 Y7.4310 I0.2518 J0.0791
N0770 X6.7141 Y7.4182 I0.2274 J0.0851
N0780 X6.7198 Y7.4062 I0.1975 J0.0869
N0790 X6.7247 Y7.3974 I0.1673 J0.0863
N0800 X6.7304 Y7.3882 I0.1516 J0.0888
N0810 X6.7386 Y7.3771 I0.1374 J0.0923
N0820 X6.7695 Y7.3476 I0.1239 J0.0993
N0830 X6.7776 Y7.3421 I0.0989 J0.1368
N0840 X6.7861 Y7.3371 I0.0958 J0.1502
N0850 X6.7950 Y7.3324 I0.0929 J0.1651
N0860 X6.8074 Y7.3268 I0.0923 J0.1866
N0870 X6.8204 Y7.3218 I0.0899 J0.2162
N0880 X6.8341 Y7.3174 I0.0874 J0.2517
N0890 X6.8485 Y7.3137 I0.0847 J0.2943
N0900 X6.8634 Y7.3105 I0.0816 J0.3453
N0910 X6.8785 Y7.3079 I0.0777 J0.4066

This is another sweeping curve that uses a bunch of line segments to complete the arc.

N1630 G01 X7.7780 Y6.6682 F170
N1640 X7.7775 Y6.6666
N1650 X7.7691 Y6.6421
N1660 X7.7683 Y6.6400
N1670 X7.7529 Y6.6040
N1680 X7.7517 Y6.6016
N1690 X7.7394 Y6.5788
N1700 X7.7381 Y6.5766
N1710 X7.7242 Y6.5554
N1720 X7.7224 Y6.5529
N1730 X7.7069 Y6.5338
N1740 X7.7047 Y6.5314
N1750 X7.6920 Y6.5188
N1760 X7.6900 Y6.5170
N1770 X7.6810 Y6.5096
N1780 X7.6801 Y6.5088

There is some logic in Sheetcam to determine when to use arcs and when to convert those to linear moves.

Basically I'm wondering if there is something in this code that could be changed to smooth things out at higher speeds or if I'm just up against the physics of the machine and/or software.  Anything you guys can suggest would be greatly appreciated.

Thanks in advance.

88

General Mach Discussion / Going into exact stop in small arcs

« on: October 07, 2010, 05:11:02 PM »

Has anyone seen this before?  It seems that when ever the machine reaches a small radius, it goes into exact stop mode and completes the radius as short, abrupt segments.  I have constant velocity mode selected.  I haven't changed the Mach setting in months.  The only thing I did was upgrade Sheetcam.  Larger arcs are fine.  Seems like any arc smaller than about 1/2" radius goes into exact stop mode.  Below is code segment.  This code goes into exact stop mode.   The repeating pattern I see is a short G01 move followed by a short G02 arc move.  I'm not sure why that's happening or if it should be happening.

N0390 G01 X4.9800 Y2.9950 F75
N0400 G02 X4.9821 Y2.9923 I-0.0223 J-0.0201 F75.0
N0410 G01 X4.9940 Y2.9757 F75
N0420 G02 X4.9954 Y2.9736 I-0.0244 J-0.0175 F75.0
N0430 G01 X5.0062 Y2.9555 F75
N0440 G02 X5.0073 Y2.9534 I-0.0258 J-0.0154 F75.0
N0450 G01 X5.0170 Y2.9338 F75
N0460 G02 X5.0181 Y2.9313 I-0.0269 J-0.0133 F75.0
N0470 G01 X5.0306 Y2.8990 F75
N0480 G02 X5.0314 Y2.8967 I-0.0280 J-0.0108 F75.0
N0490 G01 X5.0384 Y2.8733 F75
N0500 G02 X5.0390 Y2.8709 I-0.0288 J-0.0085 F75.0
N0510 G01 X5.0448 Y2.8432 F75
N0520 G02 X5.0451 Y2.8412 I-0.0294 J-0.0061 F75.0
N0530 G01 X5.0483 Y2.8181 F75
N0540 G02 X5.0485 Y2.8167 I-0.0297 J-0.0041 F75.0
N0550 G01 X5.0523 Y2.7751 F75
N0560 G02 X5.0523 Y2.7738 I-0.0299 J-0.0027 F75.0

Any thoughts would be greatly appreciated....

Thanks

89

General Mach Discussion / Jogging on toolpath screen

« on: May 30, 2010, 09:11:02 PM »

Hi all...

Is it possible to jog on the toolpath screen.  It seems to work on every screen but toolpath and settings.  I'd like jogging to be enabled on the toolpath screen as well.

Thanks.

90

General Mach Discussion / Emulated Inputs

« on: May 15, 2010, 06:24:19 PM »

Hi guys... I know I've done this before, but can't seem to get it working now.  The only emulated input that appears to work is the eStop.  I have keys set for limits and home on all three axes.  I see the LED's light in diagnostics, but when I hit the X home during a X reference nothing happens.  What am I doing wrong?   Thanks.