Messages

1

General Mach Discussion / Re: Dugong Tuning Problems, Positioning Error

« on: February 19, 2014, 12:48:48 PM »

Just to close this out, Dugong finally got back to me and sorted out the problem....

Integral Limits!!

Looking back on it now, the solution was obvious. The integral limit is set as a default to 0 with a maximum value of 65500. All other tuning I've done with Dugong drives I've never had to mess with the integral limit, and the tuning manual says to leave it alone.

Well, this time I needed to bump the limit up to around 15000 to get Ki to respond. With that all sorted the servos are happily finding 0 each time and I'm getting a positioning accuracy better than 0.0005.

Servo Tuning once again gets the better of me.

SG

2

General Mach Discussion / Re: Dugong Tuning Problems, Positioning Error

« on: February 13, 2014, 01:47:55 PM »

 Certainly something I'd thought of Hood but #1 I don't want to take down the mill since it is usually busy, and #2, the mill has been running fine and I don't want to risk throwing off the "chee". I just ordered a Granite Devices servo amp with dual motor control capabilities....given the complete lack of technical response I've gotten from either Dugong or their US distributor I think I'm going to start shying away from them. In the mean time I've got to finish a job on the lathe so I'll try and band-aid things along for a few more hours of run time.

What is utterly puzzling to me though is how the Ki function in the drive can be "dead"....?

SG

3

General Mach Discussion / Dugong Tuning Problems, Positioning Error

« on: February 13, 2014, 09:15:12 AM »

 Good morning all,

I've got a rather frustrating problem with a pair of Dugong DG2S-0080 servo drives driving a pair of Kelling 34-170 brushed servos. The issue is that my positioning error is never centering on final position. This system is on a lathe. The Z axis has a 1000 count line driver quad encoder, and the X axis has a 2500 count line driver quad encoder. Both have been confirmed to be good (actually, the 2500 count encoder is brand new). There is no appreciable noise in the system which I've confirmed with a scope. I have tuned and tuned and re-tuned again these drives. The only way I can get the position error to stay somewhat close to 0 (+/- 10 counts) is to turn the Kp and Kd gains up to the point where things start getting "buzzy". The critical thing to note here is that NO MATTER WHAT THE Kp and Kd tuning, Ki inputs (integral, error correcting over time) does absolutely nothing to the curves. This doesn't seem possible to me since it should just be math driving the transistors in the drives, but if I didn't know better I'd say the integral term in my drives was broken. The configuration software for the Dugong drives allows inputs of Ki from 0 to 65500. The response graph at Ki=0 and Ki=65500 look nearly identical with neither of them eventually landing on 0. I have these same drives in my mill with some older DC servos but identical encoders and I have never had this problem.

Any thoughts would be very much appreciated.

SG

4

General Mach Discussion / Re: Mach 3 is hanging while loading file

« on: June 07, 2013, 09:17:46 AM »

I posted this over at the Yahoo site and got no response.
I cant believe it only happens to me. If it does please give some suggestions on how to troubleshoot.
Dave at MSM suggested posting it here


When loading a file I get this
(Image deleted)
Its random but persistent.
Its a short file. About 75 lines of code. When in does not hang it takes a
second or so to calculate path.
any suggestions on how to troubleshoot?

It's 3.043.37
XP home
MSM 1.17
PC is Shuttle X50V2 1.66 Ghz Dual core Atom
Thanks
Dave

Did you ever figure this out? I'm having the exact same problem.

5

General Mach Discussion / Re: "run from here" problem

« on: June 07, 2013, 09:02:08 AM »

 I'm having the same problem except I'm using FeatureCAM and it is both starting from the beginning regardless of where I "set next line" and "run from here". It then slowly cycles line by line to the line where I had specified the "Run From Here" to be. Additionally, my toolpath is extremely slow to generate. This particular program is a 3D machining toolpath with approx. 22k lines of code. The post processor is configured to define 1 digit code numbering increments. When initially loading the problem I'm hanging on just the 19th line in a G54 command.

I suspect the "Set Next Line" and my initial loading issues are related. Has anybody made any headway on this?

6

General Mach Discussion / Re: RoboTool CVM-1 upgrade

« on: February 12, 2013, 10:27:30 AM »

 I wouldn't settle for anything less than 1000ppr quad encoders. The ones that came with my CVM-1 were complete garbage. Unless yours is significantly newer than mine you should expect to replace them.

 2hp VFD....is your spindle motor only 2hp? Mine is 3HP and the 3HP VFD I have isn't adequate to stop the motor when the spindle is going any faster than 2k RPM (it over-current faults). I mostly blame it on the garbage Hyunyang VFD I'm running. It doesn't have the circuitry installed for an external braking resistor. I'm going to upgrade in a couple weeks to an Automation Direct 3hp VFD with the braking circuit installed. This should help significantly. You might consider returning the Pendant you got from CNC4PC in favor of a USB based on from vistacnc.com. I have two of those units and they are amazing and dead simple to set up.

Good luck.

7

General Mach Discussion / Re: RoboTool CVM-1 upgrade

« on: February 12, 2013, 09:20:24 AM »

 Great! I have had excellent experiences with Arturo's stuff even though the technical documentation has much to be desired. Once it is running, it runs very well. Arturo is also fast to respond to any questions or concerns you might have.

Even though I too have a VFD running my spindle I have the brake tied into my estop circuit to rapidly stop the spindle in the event of an emergency. I also have the VFD activate the brake whenever it is not running. The linkage for the brake would be extremely easy to fabricate and I would encourage you to consider doing this as a secondary means of keeping the spindle locked when desired.

What are you doing for servo amps?

The power supply that came with my Robotool was grossly inadequate. The transformer was only 400W with a 1000Mfd capacitor. I would be surprised if yours was much different.

If you need to build a new PS, get a Toroid transformer from Antek, preferably 750W. You'll then need a 15k Mfd capacitor bank and a bridge rectifier rated to your output voltage and current. The transformer will want to be 45VAC output since the voltage gets bumped by 1.4x when you run it through the rectifier. (This is assuming your motors are rated to 63V like mine are). I'm actually going to be upgrading my motors next month to larger DC Brush servos and will need to upgrade my PS transformer when I do so....might have this one for sale. Contact me privately if you might be interested.

8

General Mach Discussion / Re: Mach Turn Index Pulse and IPR question

« on: January 15, 2013, 02:02:38 PM »

 I thought it was linear but after getting the VFD settings straightened out it was clear that the 0-10V output is actually rather chaotic. Guess I'll just live with it for now and look forward to the release of Mach4 Turn some time in 2074....



SG

9

General Mach Discussion / Re: Mach Turn Index Pulse and IPR question

« on: January 15, 2013, 08:52:40 AM »

ual;l; I got the spindle close enough to be called "good for now". Changes to the spindle motor tuning in terms of steps/rev, max velocity and acceleration have 0 effect on the PWM pulse as best I could tell. I ended up setting steps/unit to 60 and then maxing everything else. With my particular VFD (Durapulse) there was a series of analog gain settings which define a linear relationship between control voltage in and the resulting motor frequency output in Hz. Once I got this dialed in to my particular settings I used the spindle autotune calibration routine within Mach to tune the actual voltage output from the C32 to the VFD to provide as linear a response as possible. I really like the concept of the auto tune, and even the initial autotune sequence. What I don't like is that I can't manually adjust particular control points after the control offsets have been established. What would be awesome (Brian and Mach4....are you listening?? ) is if you could interact with the resultant offset graph after the initial tuning run my just pulling on control points with the mouse. The control voltage output from my system is not linear so a modifier every 10rpm or so is necessary to keep the resultant voltage linear. It would also be cool if you could define the delta between each control point, so if you needed finer control you could have control points every 5 RPM while somebody who doesn't need it that precise could have control points every 50 rpm.

Anyway, for the most part when I key in an RPM, it gets to within 20rpm of the setting which is good enough for now. The only blip I still get is between 1700-1850. If I key in 1650 the rpm goes to 1650. If I key in 1700 the rpm goes to 1820. 1840 gets me 1890, and then 1900 gets me 1930. 2000 gets me 2000. Up to 1650 I get within 20 or so of the set rpm. If I could have access to the control points I could manually modify the particular range of interest, or better yet, have the auto tune actually get the curve right

That might be asking too much.

10

General Mach Discussion / Re: Mach Turn Index Pulse and IPR question

« on: January 14, 2013, 04:08:08 PM »

 That was the route I was going to try tonight. 2000 RPM is my desired maximum spindle speed within Mach and is what I have for a maximum speed in the pulley dialogue. S2000 gives me 10V out, so I think your method of tweaking the maximum Hz output in the VFD to make a true 2000 RPM @ the spindle is a good premise. I now have these auto tune parameters driving a strange adjustment curve which could cause issues. You mentioned the linearity.dat file....if I find that and delete it should I be back to a linear curve in my PWM output?