Messages

81

General Mach Discussion / Re: Spindle direction control

« on: June 26, 2007, 05:58:08 PM »

I spent more time on the problem today but no improvement.
Reinstalled Mach3 v2.076 but that was no cure.

My actual speed reduction is 3000rpm motor to 2000rpm spindle.
At one stage today if I increased the S value the spindle revs went down and then at higher S values they started to climb again!!!.
I tried every combination of settings but no joy.
The actual calibration sequence/result appears to be the problem but other factors are probably effecting that.
For example entering the min(start) revs in the calibration window. Sometimes when the window is opened it shows the last Svalue I had used on the MDI screen.
Other times it showed zero and would not let me alter it. other times it showed -1.#IND.
Sometimes it stepped up the Revs setting at 20Revs per step, other times 50revs per step.
The graphs drawn were variable and at the start the graph was always blank apart from the axis names.
On pressing calibrate a line would be drawn usually coming from some high off scale value on the left and oscillate towards the target line which was sometimes 45deg and other times lower.
Sometimes a stright horizontal line was drawn  at 5000rpm and the figure in the start revs DRO was 5000.

All very frustrating.
Could my high setting of 5000revs be the cause of the revs suddenly taking off above 3000rpm; I will check that tomorrow.

Cheers
tmsmith

82

General Mach Discussion / Re: Spindle direction control

« on: June 25, 2007, 05:00:11 PM »

Just had another play around and in the spindle calibrate screen 'control' box appeared   -1.#IND.
I am sure I have seen this before as well.

I wonder if some of my files are corrupt and this is causing my problems.
\anyone know which file controls spindle calibration?

tmsmith

83

General Mach Discussion / Re: Spindle direction control

« on: June 25, 2007, 12:29:00 PM »

HI Vmax, thanks for your continued interest and help. I would love to get this sorted.

Right - I have only a single pair of pulleys so no flexibility there.
Motor speed is 3000revs on the case but that is at 80volts. It is actually being run at 130volts so really I have no idea what its top speed is.
The pulley step down the speed in a 2:1 ratio.
So now I am uncertain. should I set all 4 ratios to the same value.
I also wonder why the pulses per rev which is 1 in the box on the calibration screen cannot be altered when it says a zero should be entered for 1 pulse /rev.
I have still got three of the 4 slots taped over so 1 pulse /rev.

tmsmith

84

General Mach Discussion / Re: Spindle direction control

« on: June 24, 2007, 01:56:40 PM »

Does the graph stay like a Z. Well I have just done everything again and hre is what happened.

First went to MDI screen and entered various S values see below.
S1000   0RPM
S1500   417RPM
2000     815
2200     966
2400     1133
2600     1292
2800     1441
3000     4994
S0        0      I should have left things like that, but read on.

Selected spindle calibration
Calibration screen blank, as usual.  P0.25 I1.0 D0.3
Pulses/rev 1,  Control 50 RPM 0, No1 pulley Control ratio  0.0441

select autocalibrate  control 100RPM control ratio1.000

A 45deg yellow line drawn across calib screen. Blue line drawn swooping down and curving to gradually meet 30deg yellow line.
control shows 3000 rpm jumping 1000 to 5000 but spindle on high speed.
Window says successful test-save results  YES
Spindle switched off and Mach rebooted.

Again selected auto-calibate.
Control   RPM
200        0
210       0
240       0
270      0
300      0
330      0
360      0
420      0
450      100
480      102
570      400
lost track, figues increasing too quickly to record.
Saved result after which dro showed control 3000 5010RPM
Clicked 'update PID'  nothing happened.
Going back to main screen Status bar said 'Too fast for pulley - using Max'
Rebooted Mach.
On MDI entered M3,S10 and got immediately top revs
rebooted Mach
On MDI screen M3 S100 1330RPM
s150    5027RPM
S50     5027RPM
S0       5027RPM
M5      0RPM

Thoughts on all this?!
tmsmith

85

General Mach Discussion / Re: Spindle direction control

« on: June 24, 2007, 12:36:33 PM »

Will do.

tmsmith

86

General Mach Discussion / Re: Strange backlash compensation

« on: June 23, 2007, 03:47:48 PM »

HI Bertho,
I tried backlash as well and had exactly the same result, I thought I had developed some electronic/mechanical problem.
I switched off since I didn't like the action and didn't need the accuracy.
It seems a little disconcerting in use, I wonder if it could not be a little cleverer and slow down impercepably  rather than the stop start routine.
I was only looking for 5thou correction which isn't much.

tmsmith

87

General Mach Discussion / Re: Spindle direction control

« on: June 23, 2007, 03:36:04 PM »

I have tried the default button; control  remained as previous post.
Recalibrated spindle,  still no difference.

I don't class my control as good control though the RPM indicated varies very little for any particular value of S.
Setting of S upto about 2000 gives steady increase of revs but still low figures.
S2900 to S2990 steps the revs up to 5000RPM from around 2000RPM. S2960 gives around 3000RPM.
Not condusive to correct setting of Revs when cutting metal

Just a thought, is a reboot required to make Mach take notice of a new set of calibration data.

tmsmith 

88

General Mach Discussion / Re: Spindle direction control

« on: June 22, 2007, 02:36:44 PM »

HI vmax,
sorry for delays in replying but bad computer crash put computer in dock.
To carry on from where we were.

Taped over 3 small slots set pinout to INDEX - active low.
not sure about PID; there are values in there but nothing selected.
Min PWM set at 10%

On MDI screen entered S1500, M3   indicated RPM 1100  good control.
                                 S1800                      RPM 1390    "        "
                                 S2000                      RPM 5000    "        "

As you see sudden increase in revs for small increase in S.
A question; could the spindle calibration be the cause.
I do not understand the calibration. It increases the requested speed in increments of 20 and draws a graph.
After  it finishes there are some buttons to press, not sure about the order but then what happens to the data.
My graph is more like a Z than a 45deg slope and this may be the cause of the above strange behavior.
I am sure it was not like that in an earlier period.
I will await your comments before recalibrating

tmsmith

89

General Mach Discussion / Re: Spindle direction control

« on: June 17, 2007, 05:27:00 PM »

Vmax,
Tried Timing as opposed to Index. It gave a steady reading of 4520rpm. However when I changed the speed the rpm stayed the same!!.
Tried auto-calibrating the spindle. It started at a fairly high speed and gradually reduced it to zero. I am sure when I did this some time ago it took the speed up from a low value to a high one.
In fact spindle speed control seem to be poor; I think its time to look inside the box.
When on Index setting I tried increasing the debounce to 5000 but it made no noticeable difference.

tmsmith

90

General Mach Discussion / Re: Spindle direction control

« on: June 15, 2007, 05:30:03 PM »

I am using the CNC4PC insex pulse board sensing a disk on the spindle with 4 slots, one larger than the other 3.
So the high figure displayed may be 4 times the speed.

Thanks for the rundown on  the spindle display vmax. I shall put that in my manual for when I get to threading, it sounds very useful.

thanks
tmsmith