Messages

101

General Mach Discussion / Re: Motors stalling, losing steps

« on: February 07, 2009, 01:59:26 PM »

No, I'm using the vending machine power supply that is supposed to be regulated. Ooh, I found some 6800µF caps, I have 3 of those .. that gets me closer..
I appreciate your help more than you can imagine

102

General Mach Discussion / Re: Motors stalling, losing steps

« on: February 07, 2009, 01:35:24 PM »

Hood, I tried the pulse width, along with, or without sherline mode, but then the motor just turns very rough. Gecodrive says to use a pulse width of 2, which does seem to be the best.

You know, the more I work on this, the more I think I've got some sort of voltage drop, or signal noise. While a jog key being held does cause minor twitching of the motor, there's still something else. I thought we had it figured out, until I let it run some straight line programs, 300mm one way, 300mm back. Sometimes it's within 5 seconds of starting the program, sometimes it takes 30 seconds or more, but I can hear the motor 'twitch' once in a while, and it usually stalls if there's any load on it. If I put the motor on the table and run the program, when the twitch happens, it actually jumps, like it tried to change direction, or stop instantly for just a split second.

I've been reading looking for how to hook up a capacitor to filter the power supply, but the numbers I was coming up with weren't in the realm of reality. Geckodrive says:

(80,000 * I) / V = C
Example: Using a power supply of 65V and 5A, the equation would look as follows:
(80,000 * 5) / 65 = 6153µF
So, for me it's like this:
(80,000 * 19amps) / 48volts = 31666µF capacitor ... I think I might have a hard time finding a cap like that around here ..

The last thing I thought of is line noise, but I have a spare motor with the factory wiring, hooked right up to the driver, and the twitch is still there.

EDIT: I wanted to mention that this problem has existed ever since my first setup of this machine. I started with a hobby cnc drive, and that did it too. I've tried a completely different computer with a fresh install of windows xp and mach 3. I bought this new G540 drive. I have a couple power supplies, ranging from nothing more than a rectifier and capacitors on a transformer to an vending machine power supply, and several others. I've tried unipolar, bipolar, parallel and series wiring.

I may go bald by the time I figure this out >.<

103

General Mach Discussion / Re: Motors stalling, losing steps

« on: February 07, 2009, 10:45:22 AM »

Just for the sake of helping others, I'm going to post my latest findings.

After speaking with the very helpful tech support at geckodrives, I learned a couple things. First off, Parallel mode for these motors is supposed to be fine, though if I were to keep it in parallel, a 3.3 ohm resistor on the set pins would have worked, because the G540 will limit its output to 3.5 amps anyway.

I was getting a reading of around 80 degrees C, and it was making me nervous. According to tech support, this is normal, and acceptable (up to 100 deg C), however for the sake of not burning myself on the motors during tool changes, and the longevity of the motors and drivers, I decided to rewire in series.

My latest problem was this mysterious ticking noise coming from the motors (all of them, on any axis), with a steady, repeating 'skip' in the motor about every second or so.  This skip was (and still is) causing stalling when the motors are run at moderate speeds. I did everything I could think of to the computer. It's a 3 ghz pentium, with bare-bones windows xp on it. I did all of the performance suggestions from the support area here, along with every other tweak and setting I could think of with NO CHANGE. I just could not get rid of it.

More or less by accident, we found out in the end that it has something to do with the jog keys. I haven't found a way around it yet, but if I give a motor a G0X1000 command, it will run smooth as can be, but if I hold a jog key down, I get the ticking (and stalling) which still needs to be sorted out, as I can't have the motors stalling during jogging over for a tool change. I'm going to try a specific keyboard driver rather than the windows system one, and see if that helps.

104

General Mach Discussion / Driver changes, suggestions?

« on: January 09, 2009, 11:30:23 AM »

Good morning,

I'm planning on making some changes to my machine. It turns out that it's running in unipolar mode with a set of KL23H276-30-8B. I'd like to run these motors in bipolar mode, but my current controller doesn't offer it.

I've looked into the gecko drives, but I like to shop around. Any other suggestions for reasonably priced bipolar motor controllers?

Also, I don't see the answer on the gecko site, do all gecko drives support bipolar mode?

TYIA ~

Z

105

General Mach Discussion / Re: Limiting rapid rates in mach 3?

« on: December 30, 2008, 06:56:13 PM »

Very possible it's an old version, I'll update it asap. Thanks again

106

General Mach Discussion / Limiting rapid rates in mach 3?

« on: December 30, 2008, 06:15:19 PM »

Hello again all,

I'm wondering if there's a way to force mach 3 to never exceed the settings in the motor tuning menu.

Right now, if I set my feedrate slider above or below 100%, the rapids change speed too, which I don't want.

Reason is, if I'm cutting a design on hard material, I sometimes pull the feed rate down a bit, which also slows the rapids. Of course, it does it the other way too, if I'm working in very soft material, I crank up the feed rate sometimes up to 200%, and the rapids run extremely fast.

Is there a way to do this?

Thanks!
Z

107

General Mach Discussion / Re: Motors stalling, losing steps

« on: December 26, 2008, 10:51:10 PM »

Thanks a bunch for all the replies guys, all of the ideas here give me some direction. I'll be trying each of these until I either go bald from pulling hair, or until the problem is fixed.

108

General Mach Discussion / Re: Motors stalling, losing steps

« on: December 25, 2008, 07:22:33 PM »

I've done tons of testing with different velocities and acceleration settings, and it seems as though these steppers should be able to handle the speed. I've moved on to testing software and signals, as it really doesn't seem to be a mechanical problem. I've run the X axis until it stalled (took 8-9 full passes across the table, cutting air), then turned off the controller and the screw turns easily with my fingers, it's not even the slightest bit bound.

I should also mention that throughout the course of the day, I had the machine in 1/8, 1/4, and 1/2 step mode (recalculating steps, velocities, and acceleration for each) and none of that seems to have helped. Neither has pulse width, sherline, or anything else.

I just ran the Driver Test software, and I do see some spikes here and there. I'm going to go through the xp optimization again, swap out parallel cables, check grounds, and re-route some cables... it really seems like some sort of signal noise. If none of that helps I'll try the amp settings you mentioned.

Thanks for the reply on Christmas night !

109

General Mach Discussion / Motors stalling, losing steps

« on: December 25, 2008, 06:21:55 PM »

Hello all!

I have a smaller machine that has a set of 3 Keling  KL23H276-30-8B steppers on it.

I recently started doing some different machining that's requiring more speed than I usually run, but a problem that's always existed has now come back to bite me. Since I got the machine, it's always had this little glitch. You'll be jogging an axis, and as it goes along, it will suddenly make a very short 'stalling' sound, for lack of a better term. Normally the axis will continue on its way happily, but now I've been trying to ramp up the speeds and when it hits these 'spots', the axis starts losing steps (axis stops, whining noise from stepper like it's stuck)

This can happen on any axis, and in any location on the axis, however it seems to usually happen in the middle area, as if it's determined by how long the motor has been running. Unfortunately, the controller is some generic thing that doesn't appear to have brand name on it.

Anyway, I've been scouring the forums, and tried tons of tricks I've read, but can't get this to go away. As far as I can tell, it's not mechanical, everything moves nice an free, no binding. I'm running a 3.0ghz pentium desktop with nothing installed but mach and windows xp, though it's entirely possible it's the pc causing the problem I suppose, I have no proof either way.

I'm kind of at a loss here. The steppers seem to sail along flawlessly at high speed other than these glitches. I know I haven't covered all the bases as far as testing goes, but I thought I'd ask here, hopefully you guys can save me some time.

TYIA ~
Z

110

General Mach Discussion / GetOEMDRO(815) returns zero? Why?

« on: September 24, 2008, 11:25:24 PM »

Hello,

I've spent hours on the silliest problem. I have a script that uses
GetOEMDRO(815)
GetOEMDRO(814)

These are supposed to be for estimated time and elapsed time.

They both return zero, even though I can apply that value to a DRO in screen4 and the boxes count like they should.

When I try to go:
Myvar = GetOEMDRO(815)
or
msgbox GetOEMDRO(815)

it returns zero. I thought maybe I needed to dimension a variable to hold a date or time, and that just returns "12:00:00PM"


The purpose of all of this was to save the elapsed and estimated time to a file every minute or so, so the file could be read remotely to see how much time remains. I also have a lot of experience with AutoHotkey, and so far, I have been unable to extract the value of the text boxes either. I'm really stuck.


What am I doing wrong?

TYIA!
Z