Messages

971

General Mach Discussion / Re: Has anyone used Granite devices VSD-E sevro drives?

« on: September 09, 2009, 08:55:52 AM »

Granite has posted on their website officially that their drive can control two separate servo motors. This changes the landscape considerably.

EDIT: note that this is accomplished thur a user installable firmware update!

The product went from most expensive to least expensive in one step. I have a little homework to do on it, but it looks like I will be reviewing the drive since it is now definitely priced competitively.

I am about done with the CNCdrive product reviews (Dugong and Whale3), but I have sold the 4th axis prototype and will be making a new one from scratch which will take a while with my current schedule. The servo drives are targeted at the 4th axis, so until I have the next prototype built, there is no sense in reviewing a drive for it. Stay tuned though.

972

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: September 06, 2009, 04:51:02 PM »

Current prototype is sold, so I will be fabricating a new 4th axis from scratch, this time with manufacturing considerations as a requisite.

Any suggestions for useful features are welcome at this point. For a production version, a belt guard will be incorporated into the design.

973

General Mach Discussion / Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine

« on: September 04, 2009, 02:59:03 PM »

Yup, nice job on the repair, hope those tiny wenie little critters with 471 marking don't need changing, just look at the size of them compared to the 8 pin DIL package... we'll need a soldering iron the size of a pin !

Yep, them there were the SMDs that needed to be replaced. I got away without changing the 'legged' SMD IC chips nearby as they were OK. I got instruction on how to check them out with a scope, but I only have a software scope and I have used it, but don't really know what I'm doing with it. So the SMD ICs 'check out' came with power on and see if the motors move . . 

As to the e-stop topic, anyting is possible, but an outright runaway crash into the table stops is pretty unlikely with reasonably current electronics, methinks, as the drives (not sure about the Viper, but *probably*), have encoder sensors that will shut down the motor if the encoder dies or becomes scrambled or otherwise unreadable. This is separate from a normal servo 'following error'. The more likely scenario is a broken tool or stalled spindle nowhere near the table stops. If the machine keeps on truckin', things can go from bad to worse in a hurry . . .  like the spindle crashing into a fixture or something equally fun . . none of which will be caught by a table stop, but would most likely cause a following error which is what you want to stop the movement and possibly (but not necessarily) the spindle.

Seems like you've got a plan scoped out, though. A caveat with the Dugong and Whale3 is that the error line doesn't have enough power to drive the BOB input reliably, so a little circuit has to be constructed for the interface.  Post back if you have any similar issue with the Viper and I can post the schematic for the little driver circuit I devised. I would post it now except that CNCdrives has suggested a better alternative to what I came up with and I would want to check that out first.

974

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: September 04, 2009, 09:59:06 AM »

OK folks, I got the Dugong drive and ran the 4th axis up to full speed with a 4" chuck and a hunk of cast iron in the chuck. I also changed from 3:1 to 2:1 ratio for the first time  . . zoom! Max accell/decell it would handle. Shaking my whole workbench!  I'd call it a success. The thing is scary . .LOL!
I'll make another video when I get a chance.

There is a lot of interest in 4th axis and I am considering making a limited production run of these machines, possibly for the European market, where most of the interest comes from. I am in the process of redesigning for production. The drive belt mechanism works fine, but is too complicated (read expensive) for the target market. Conventional trapezoid tooth profiles are also too noisy at full speed. I'll be going with the newer GT2 belt system and no idler. I'll be looking for a vendor to produce the spindles, preferably in Europe, so anyone interested in that can send me a PM.

The current iteration was intended as final so it is nicely finished and has the index photosensor on it and is ready for prime time. The only part used from an off-the-shelf indexer is the spindle and I already bought a Phase2 indexer quite a while back when they were on sale, so I have another spindle. I have to make everything else over again except the frame, so before I take the current 4th axis apart and trash all of the pieces, I thought I'd offer it up for sale if anyone is interested. I'd take a reasonable offer and just start over from scratch. It seems shame to waste a working prototype. Better someone using it than just having huge custom made timing gears and belts sitting on a shelf.

In any case, keep watching for more refinements and higher speeds. My new drive design is finished and I ordered the new belts, pulleys and aluminum stock today. If I have time, I'll design and build a prototype spindle; longer and with a threaded nose to accept a conventional chuck, but with my schedule that is unlikely this time around.  

975

General Mach Discussion / Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine

« on: September 04, 2009, 05:47:07 AM »

The drives have been given a good work out for a week now, they maintain accuracy and run very cool, and have not needed to be reset.

The drives should not need to be reset unless something goes wrong. And sooner or later, something goes wrong. What is important is that the drives are able to initiate an e-stop in Mach. I strongly suggest you set up and test that function before you have need for it.

According to the manual, the Viper200 should be able to be reset by cycling the control power without killing the HV, so that part shouldn't be an issue.

976

General Mach Discussion / Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine

« on: September 04, 2009, 05:29:14 AM »

Thanks for following thru with that, Derek. A downspec version of the Viper200 is what I *thought* I was getting because that is the manual Larken was providing as the Viper95 manual when I made my purchase. Larry Kenny informed me that he has updated the manual and the Web site and I added that info to the review. It is important that people keep in mind that the Viper200 and the Viper95 are not just different versions of the drive, as is the case with other models. They are totally different products. The Viper100/200 had the features I was looking for. The Viper 75/95 did not.

Just as an interesting note: because of my own mistake, I killed the Whale3. But with detailed  instruction from the vendor, I was able to repair the drive!    This is what happened:

I was testing all of the servo drives with a variety of motors and one was a 35V NEMA23 which I ran with 72V thru a 1ohm wound power resistor in series with the motor. At first power up I had the leads reversed and when I changed the wiring in a relatively inaccessible area, I ended up with the motors leads connected to each other and the Whale3 outputs connected to either side of the resistor. Not good.  The drive tolerated this abuse for (as a guess) about 20 seconds before vaporising two traces on the board. I corrected the wiring and fixed the traces, but on power up, the fuse on the main PS popped indicating a dead short in the Whale. I have a little bit (enough to be dangerous) of prior experience with MOSFETS and knew that they fail shorted, SO that was my "electronics for Dummies' level diagnosis. I removed the MOSFETS and sure enough three of the four were shorted.  

So informed CNCdrives what I had done and told them I did not expect a warranty repair, but would appreciate any advice they might be willing to share. To my surprise, I got a very detailed instruction on how to trouble shoot the problem, track it thur the drive, and what parts to replace (including part numbers) and in what order!  I'm no electron whiz, but I CAN follow instructions so I bought  the parts ($6 total). I've done plenty of desolder/solder stuff, but never any SMD, so I watched some instructional vids, bought a temp controlled iron and some other SMD tools and practiced on an old VGA card and some memory sticks. Parts came, fixed the drive and its running fine!

977

General Mach Discussion / Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine

« on: August 28, 2009, 05:03:02 AM »

The Dugong limits current to 35amps. It will allow a small momentary overcurrent (no spec on that).

It does not fault (stop the drive) for overcurrent situations, although it does have an phsical LED on the drive and the tuning software has a virtual LED to indicate current limiting is active.

The drive will fault if the overcurrent exceeds 40amps and is not controllable by the drive, for example with a short circuit.

I also learned that the fault lines and reset lines of the drives can be combined so that a fault on one drive will stop all of them and all can be reset with one line.

Yesterday, I was messing around with the Dugong and I had Mach running a test program while I simultaneously watched the servo drive diagnostics on a laptop.  changing a PID parameter and then immediately rerunning the same test program IN MACH is definitely the hot setup.

Earlier, in my office, I had Mach running a test program and the Dugong tuning software running simultaneously on one of my render slaves (Core2 duo). Can't say if all of that power was needed, but both apps ran fine together and MACH never hickupped at 60k kernal speed, so it is definately doable.

So far, so good.  

978

General Mach Discussion / Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine

« on: August 27, 2009, 06:43:13 AM »

I will check that out and post back.  Last night I finished connecting my new control box to the mill and got the faults and resets working. To monitor faults, I have lights on the box for faults  (and it stops MACH) and simple reset buttons also on the control box.
 
Reset on Whale3/Dugong is  just grounding a 5v reset line so it could be done from MACH also. Rutex requires cycling the 24v digital supply so it would need to have a relay rigged up. I'm just using an on/off toggle for that.

As to over-current, by way of example, the Gecko does not fault at max amps, it just limits it there. That is what I *think* the Dugong does also, except that if the overage lasts a certain amount of time, it will then fault, but let me make sure and post back. As far as I know at this point, you cannot turn off faulting on the Dugong.

After to performance and the cool software, the big advantage I see in the Dugong is the automatic handling of the braking resistor (the one they sent me is friggin' HUGE!). I am aware that the user can and *should* build an external braking circuit and I have seen a couple of schematics for how to accomplish that, but I suspect few people actually do because I never read "my braking circuit failed', but I read over and over "my drive burned out. The built in pre-engineered braking circuit is perfect for 'electronics for Dummies' level guys like myself.  *Theoretically* it should be impossible to burn up a Dugong drive. I am going to beat up on it as much as possible, but I do not have a big enough motor to really get it's attention.

979

General Mach Discussion / Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine

« on: August 26, 2009, 07:52:44 AM »

Added review of two more drives, both from CNCdrive. Same link.

The Whale3 and the Dugong    . . . NEW WINNERS!!

Anyone contemplating buying servo drives will want to read this.

980

General Mach Discussion / Re: Mach3 Customization/Macro Programming Documentation

« on: August 26, 2009, 05:14:12 AM »

Simpson I do thank you for your work on servo drive reveiws, it was something long overdue.

Thanks. I'll be adding the two new drives I received in the mail last Saturday. These are brand new models from CNCdrive in Hungary. I'm happy with the drives so far.

Tuning is not too bad comparatively speaking, but automatic tuning is planned. That should be interesting.

Performance is excellent and with some luck we will be able to communicate with these drives in real time while MACH is running with the new script capabilities.