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Author Topic: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine  (Read 29034 times)

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Offline simpson36

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Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #10 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.

« Last Edit: August 27, 2009, 06:50:57 AM by simpson36 »

Offline Hood

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Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #11 on: August 27, 2009, 09:00:17 AM »
Sounds like they are nice drives and are coming closer to the functionality that I have with mine. Mine would cost 10 times the amount these do though so they do seem a great deal.
 I would imagine if they limit the current then the drive would fault, not on overcurrent perhaps but following error. This would be easily sorted with tuning I would think,  as long as the rapids/accel were still acceptable, due to detuning, which they likely would be :)

I like the protection of the shunt resistor, still not quite as functional as my drives but again they are a fraction of the cost so cant possibly grumble about that and they certainly sound like they are way ahead of the competition.

Hood.

Offline simpson36

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Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #12 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. 8)

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.  
« Last Edit: August 28, 2009, 05:12:56 AM by simpson36 »

Offline Hood

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Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #13 on: August 28, 2009, 05:12:54 AM »
Sounds an excellent drive :) Thanks for the info.

Hood
Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #14 on: September 03, 2009, 04:51:51 PM »
Here is a quick review of the Viper 200.

My Colchester / Ailam Crusader control went U/S so required a rapid conversion to Mach + new drive system.

I contacted Larken and explained I needed the drives quickly. I ordered 3 - 2 for the machine + 1 spare.
These were despatched swiftly with all connectors / jumpers and a programming lead included.

The PC boards apear to be wlll constructed and finished, I could not see any mounting or soldering defects. Nice...
It took a few weeks to design and build the new control system, Viper manual is up to date, (manual should recomended / detail using fans / additional heat sinks if end mounting).

The drives were commissioned as per the manual, powering up the logic side and checking coms - no problem there.
Check of the PSU - OK 130VDC
Power onto the drives, YES, we have movement.
Tuning is easy, if not a bit of a guestimation exercise - the manual does give some help but its a bit thin (fortunatley my business partner has designed small digital servo drives so understood the PID settings and generally how to tune by feel.)
The tuning process took about 1 hr per axis, checking the stiffness of the drive and ensuring stability. All done manually, i.e twist the pulley by hand and check the movement of the axis on a dti.
Overshoot is the most difficult thing to detect and tune out.

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.
Well pleased.
The Anilam control had max rapids of 4m/min...quick test with the Vipers we had this up to 6m/min (and could have got more) but having just got the lathe working again and not wishing to break it, we set the max rapids at 4m/min

The only thing I would like to see is mounting recomendations in the manual and a graphical means for seeing the motor position vs demand signal to aid tuning.

The CNC Drives Dugong looks interesting - might try these to replace my stepper driven Bridgeport drives...mmmm.. decisions decisions.

Either way, the Vipers do a good job. ***Recommended***

ATB
Derek

You can "chop it off" but can't "chop it on"

Offline simpson36

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Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #15 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!  ;D  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!




Offline simpson36

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Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #16 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.

Offline Hood

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Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #17 on: September 04, 2009, 08:48:49 AM »
Good job on the repair, see, like me, you also like to do a bit of platic welding at the same time ;D

Hood
Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #18 on: September 04, 2009, 11:14:42 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.

Hi Simp'36,

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 !

I have done some SMT work myself and hand soldering that stuff is almost as hard as the strain on your eyes.

Re: the Viper 200s, my estop circuit is hard wired (mushroom head crash stops and "very"end of limit travel switches) at the moment, nocks out the spindle VFD as well.
Next step is to wire in the 1st satage travel limits and the Viper fault signal to the BOB Estop I/P . This will disable the step / direction OPs to prevent any further movement.
The "very" end limit will kill everything in the case that a drive has run away.

that is the philosophy anyway :-)

Those Dugongs do look good though ;-)

ATB
Derek
« Last Edit: September 04, 2009, 11:17:26 AM by derekbpcnc »
You can "chop it off" but can't "chop it on"

Offline simpson36

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Re: Servo Drive Review. First 4 drives Gecko, Viper, Rutex, Leadshine
« Reply #19 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 . .  :-X

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.