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331  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 30, 2012, 11:21:10 AM
Found the problem finally Smiley!!! It appears that Autotuning is seriously broken in the Ultra 5000. Once you have used this feature the drive goes crazy and is virtually impossible to tune. After using the Autotuning you have to reset the drive in order to get things back to normal.

No this crazy buzzing has stopped for me and I can at least try and tune the system Smiley

Dan
332  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 30, 2012, 12:50:08 AM
Ah... no, it's the same with the 5000. Also have the step current there, but again no matter what (changing the step current as well) the autotuning gives same parameters.

I tried the inertia thing and it didn't make any difference at all.

I went back and removed the belt and so tried to tune the motor alone, but interestingly I was not able. Exact same values that worked for me before, didn't this time and I couldn't tune it any better than with the chuck together. Really have no clue what's happened.

Dan
333  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 29, 2012, 02:23:17 PM
Oh... and one another question. In the custom motor setting window there is a parameter called "Inertia", may be if I enter there a value accounting for the chuck inertia it will help? Or shouldn't I do this?

Dan
334  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 29, 2012, 02:17:33 PM
Thanks guys. I checked the custom motor parameters and found a small discrepancy: torque constant was set to 0.389 instead of 0.336. I fixed it, but this is a small error and I don't think it would be that much of a problem. But I will play with tuning tomorrow to check. Oh... and there is a parameter in the Ultraware motor editor called "Rated voltage" - the one that I filled in there was "Maximum bus voltage" from the motor specs. Assume this one is correct.

Hood, I am not sure which parameter you mean when you say you had to increase the current to 50% or more.

I tried the filter, but at low values the system is very loose and increasing the filter value brings back the buzzing.

Your point regarding the low current encoder might be the case here as the encoder on this one is only 1000 lines per revolution. The images you attached are very interesting. Didn't realise it would play such a significant role on a spindle.

Dan
335  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 29, 2012, 12:04:32 PM
I am having a problem trying to tune the Ultra 5000 servo drive. Autotuning doesn't appear to work as the values it calculates don't give good performance and are the same values regardless of the mass connected to the motor.

I can't get it to hold position. It keeps producing this annoying buzzing noise. And it eats up all the current set in the current limit. If the current limit is small the buzzing sound stops and the current drawn in a standing state approaches zero as expected. But at this currents the system cannot operate as the motor doesn't have enough power.

Tried to play with all the parameters, but still can't get it stand still without producing the noise and drawing so much current.

I was able to tune the servo to fair results with the chuck removed, but have no luck with it mounted.

Does anybody have any thoughts? Must be something I am overlooking or doing wrong. JH? Hood? You set up far more servo systems than I did.

Dan
336  Mach Discussion / VB and the development of wizards / Re: CNC Grinder Wizard /Screenset on: June 28, 2012, 03:46:27 AM
Nice work, Terry!

By the way, may I ask why CNC? Isn't hydraulic much faster, quieter and simpler?

Dan

337  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 27, 2012, 09:51:46 AM
Thanks JH. Working on the spindle servo now. Programming the drive to do all the stuff I want. A few little things still left then to get it fully running: fitting the home switches, the cable carrier for the carriage, fitting a guard on the chuck with a motor disable switch and fixing the tray and guards. Got them welded already, but the tray came out horrible. It's stainless and was TIG welded, but still got seriously (and I mean SERIOUSLY) distorted.

Dan
338  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 25, 2012, 12:50:28 PM
Hood,

I had them set directly in Port and Pins. Just tried using an OEM trigger instead and it behaved absolutely strange - a single short button press and the axis doesn't stop till it hits soft limits.

Dan
339  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 24, 2012, 12:04:44 PM
Thanks Hood.

You and Russ were right about the external buttons. I just played with a simple push button in place of the tactile ones and it demonstrated same behaviour. Thought may be the controller frequency would have an effect on this, but it absolutely didn't.  Too bad it's the way it is as the jogging buttons  are almost useless Sad

Dan

P.S.

LOL... just reread my post from yesterday and it's funny how I assumed it was wire inductance.... probably was late enough to make me think not clearly Grin
340  General CNC Chat / Show"N"Tell ( Your Machines) / Re: 9x20 Chinese Lathe Conversion on: June 23, 2012, 02:39:13 PM
A good idea, Russ. Will have to test with another switch and same wire length to be sure. Could be the wire inductance playing a role (thought currents being sunk by the ESS are extremely low)... hmm... but then as far as I can tell it does start immediately, but it's when I release that it lags. I will do the test to find out.

Thanks.
Dan
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