DVR XP shuts down

[Richard Dooling]

Any DVR XP owners experienced anything like this?

My Nova DVR XP shuts down while using a buffing wheel. I've not used a buffing wheel on this lathe before and generally I will use other motors but I tried it out and the lathe shuts down under load.


I removed the wheel and mounted a bowl blank and turned with no issues.


I unplug the lathe after use so the software settings would have been at the factory defaults. I'm wondering if the software thinks a load like this means something is wrong and if the setting need changing but I can't find a clear explanation of what the setting mean. What are PI Speed Control coefficients? What do the Kprop and Kint values mean?

I hope it's not a bad board - they're not cheap!

[David M Peters]

I'm surprised that running a buffing wheel is causing any issues... I'd definitely get in touch with Teknatool on this. When the machine shuts down does it show any error codes?

But to address your other question, those properties are all PID Controller (http://blog.opticontrols.com/archives/344) constants. Sounds like the DVR uses a PI controller (described in that link), and those two values control the motor's speed in relation to what you have it set to on the RPM dial. I don't feel that messing with them will fix your problem especially seeing as how you're using factory default values.

[david privett]

could you be leaning on the buffer to hard and overheating the motor? there should be a temp. usually in C where it should run stamped on most electric motors . You could check it with a digital thermometer . I do not know for sure on your lathe , just most electric motors.

[Ralph Lindberg]

#1: Unplugging the lathe will not force it to factory default settings, those are in EEPROM and retained. You can change the factory settings, but then these changes are retained, even when the lathe is unplugged.
#2: The lathe features a "stop on catch", as I recall this can be set to one of three settings "soft", "med" and "hard", the factory default is "med". I've never gotten a DVR to stall on buffing, but maybe you are leaning into it harder then I am. You can change these settings and the instructions should be in your manual. If you are getting no stalls on turning, I suspect you maybe pushing too hard on the buffing.
#3: Kprop, Kint, etc are control system parameters and you should not try to change those unless you know exactly what you are doing (I own a DVR-XP, have and EE, I also worked in control systems and I wouldn't try changing them.
#4: I've never managed to get the motor to shut down for heat, I'm not certain what it would take but the shop was once ~100F and it worked fine.

[Richard Dooling]

Thanks everyone,

I have contacted Teknatool and sent them a short video. Just sent them a list of parameters they requested. This was accessed by entering service mode (https://s3.amazonaws.com/cdn.freshdesk.com/data/helpdesk/attachments/production/19001503237/original/How%20to%20enter%20Service%20Mode%20and%20Check%20 serial%20no.%20_%20parameter%20on%20DVR%20XP%20lat he..pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAJ2JSYZ7O3I4JO6DA%2F20170411%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20170411T203123Z&X-Amz-Expires=300&X-Amz-Signature=4d6fdce65ecba352cd75d450348c25d8432ffd7d d90543ff19998011cd0e45f8&X-Amz-SignedHeaders=Host&response-content-type=application%2Fpdf). You may have to register for the link to work but there's a lot of info in the library (https://teknatool.freshdesk.com/support/home).

No way the motor overheated as the shutdown happens within 3-5 seconds of engaging the wheel. I really don't think I was being too aggressive. I tried several times with different approaches - but I'll try again.

Ralph,
1. I may not understand exactly what they meant but this is from the manual"
Hard Reset Function
Press key <OFF>
hold it and then press key <DOWN RPM>
in order to provide the Hard Reset of the drive.
Another way is to switch off the power, wait 10 seconds and switch it on again. Use this function if you
want to return the factory-preloaded values of the drive parameters. Also, try to use this function if you
have a problem with the drive, for example, if the system is not responding to the keys.

2. This was my thought also but I didnt find the meaning of SOFT vs NORMAL vs HARD in my manual. Still have not tried this as I'm waiting for Teknatool feedback.
SOFT: For light work at speeds lower than 500 rpm
NORMAL: Suitable for most work and is the default setting
HARD: For heavy and/or ‘out-of-balance’ work at speeds lower than 500 rpm

3. I hear you!! In fact I've learned that control panel keys have functions that may be invoked by pushing specific combinations. Maybe I screwed up something in the past that I wasn't aware of because the lathe operates for normal turning.
4. I've never had heat related issues either. I'm in the Southeast and my shop gets pretty hot.

[Sid Matheny]

I use my DVR-XP with buffing wheels all the time with no problems.

[Peter Fabricius]

Richard. I am going to follow this thread, I have not had this problem with my DVR XP in the 6.5 years of ownership and very frequent use...
It will be interesting to see what the Technatool staff come up with.
I think if you just press the Program button you should see the setting for Soft, Med or Hard. Just take a look, you should be on Med setting.

[Richard Dooling]

Teknatool has been very responsive so far. They sent me some suggestions to try. I'll report back.

[Steve Schlumpf]

Richard, I do not have a DVR XP but am curious about what speed you are running the buffing wheels at? Have you tried a different speed to see if that makes any difference? Seems odd that you can turn a bowl (load on the motor) and can not run the buffing wheels (no load).

[Bill Boehme]

..... This was my thought also but I didnt find the meaning of SOFT vs NORMAL vs HARD in my manual. Still have not tried this as I'm waiting for Teknatool feedback.


SOFT: For light work at speeds lower than 500 rpm
NORMAL: Suitable for most work and is the default setting
HARD: For heavy and/or ‘out-of-balance’ work at speeds lower than 500 rpm ...



The terms Soft Reset and Hard Reset have nothing to do with how or what you are turning. Sort reset refers to resetting via software control while hard reset is a hardware controlled reset. Resetting via software may not reset everything.

I have a question. Are you running the buffing wheel in reverse? There is a possibility that a fault condition is detected because the load you are applying is greater than expected for reverse turning ... sanding is typically the only operation done in reverse.

Another thought would be that the inertial load of the buffing wheel is extremely low, but the torque load of heavy buffing creates an unexpected high load condition that doesn't appear to be normal given the low moment of inertia.

[Richard Dooling]

Lots happening on this and I'll try to give a more through recap later. I'll have some info that some DVR XP owners may find useful.

Bill my item #2 that you quote was in response to Ralph's item #2, "The lathe features a "stop on catch", as I recall this can be set to one of three settings "soft", "med" and "hard . . ." This is a function of lathe operation and how the motor reacts to turning conditions. I was not referring to a soft or hard software reset but an available parameter setting that changes motor operations.

From the manual: "You may wish to change the stabilization setting from time to time depending on the type of work piece you are working on. You have 3 options preset for you: " (SOFT, NORMAL,HARD)

Maybe I'm not understanding you?

[Richard Dooling]

This post is a recap of what happened with my DVR XP shutdown.



I was regularly experiencing a shut down when trying to use a Beale buffer. This is the first time I’ve used a buffer on this lathe.
The lathe was in forward rotation at 750 rpm and only shut down under a load.
It shut down the first time I engaged the wheel.
The display looked normal and the lathe started back up with no problem until I engaged the wheel again.
It shut down no matter how light or aggressive the pressure but turning a bowl blank did not cause a shut down.
I shut down power to the lathe, unplugged it, waited a few minutes and booted back up. Still the same behavior.
Set my hair on fire, ran around the shop, used bad language.
Came inside and contacted Teknatool and Sawmill Creek.


The next day things generally ran fine with occasional stalls.

I had several exchanges with Teknatool. They have been really trying to figure this out for me. They sent me instructions to access service mode and asked me to record all the listed operating parameters. The instructions included a chart with the normal baseline numbers. I had two settings that varied from the baseline and they sent me instructions on how to change them.

They also mentioned that there might be “noise/interference from somewhere.” I assume they mean electromagnetic interference. They advised me to try putting a ferrite choke on the main control panel ribbon cable. I asked if a big honkin’ magnet on the headstock might be suspect. Have not heard back and I haven’t installed the ferrite choke.

Wednesday I made the recommended changes to the two operating parameters. No stalls. Thursday and Friday I tried various combinations of magnet on the lathe and off, aggressive engagement of the wheel and various speeds. I tried everything I could think of to stall the motor short of causing damage to the machine or me. It has not stalled once.

So apparently problem solved. I guess changing the parameters fixed it. But day two I only had one stall and that was before I changed the parameters, so I’m still not sure just what was happening.

Thanks very much for everyone's advice and interest. I was pretty worried what with the price for a new control panel board!

DVR XP owners:

Here’s something that was not obvious when I went in to change settings.

The screen displays two parameter values at a time.
Press and hold <FWD-REV> button and then use UP and DOWN to move between the two displayed parameters. This changes which one will be edited.

This PDF includes a chart of the baseline values and my recorded values.
358405

[Ralph Lindberg]

Thanks for the update
I usually buff at 1800 rpm
Fixed field magnets should not effect the lathe (my headstock is covered with magnets and has been for, years)
EMF, ya that could, but that's a changing field.

I just had to take my tails-stock apart, the handwheel was sticking really badly. I ended up honing (brake hone on a drill) on the shaft opening of the tail-stock, then wiping it out. I'm going to guess it was wood dust ground into the fit-mit too hard for just wiping out with a cloth.

[Richard Dooling]

Thanks Ralph,

That makes sense. The magnet is not in motion so no current no EMF. Yes?

The ironic thing is that I never meant to regularly use the buffing wheel on the lathe. I've got a rarely used Shop Smith that will do nicely for this.

I've been playing around with speeds and 750 is just what I chose to go out for a test drive. Then I found myself in the middle of trying to figure out why my lathe was shutting down.

Today I was at about 1400 rpm with a pretty light touch and got some nice results. So much of the key is in the prep. The buffing actually goes pretty fast.

[Jens Bingel]

I had the same problem. Attaching a grounded wire directly to the lathe bed eliminated the problem for me. Hope this helps.

[Jens Bingel]

I am sorry, this is my first reply in this forum and I probably did this the wrong way. Jens

[Glenn C Roberts]

Jens, I think you posted correctly. Do you have a ground on the receptacle you plug the lathe into? I believe the lathe frame is grounded thru that connection. Check the voltage between hot & ground, and hot & neutral. Should be the same.

[Richard Dooling]

Hi Jens,

Nothing wrong with your post.

As Glenn says, normally the lathe should be properly grounded through the plug unless the receptacle is faulty or lacks a ground.

[Jens Bingel]

I run my lathe on 220 V and the plug, to the best of my knowledge, is grounded.

[Glenn C Roberts]

If it's a 3 prong plug, the ground and neutral are the same at the lathe, and can be checked with an ohm meter. If it is 4 prong, the ground and neutral are the same at the panel box. If you (Jens) connected a ground to the lathe frame, two things I can think of could be a possibility: The ground is faulty to or at the panel box, or, your added ground is bleeding a static build up that is affecting the circuitry of the
dvr, even though your machine may be properly grounded. Not sure how a few thousand volt static charge could develop on the lathe, or why it wouldn't bleed to machine ground, unless whatever is causing the charge is housed in non conductive plastic.

[Jens Bingel]

Glenn, thank you for taking time to think about my situation. I use the extra ground wire only while buffing. I wired the basement shop myself and there is always the possibility that I did something wrong. I do not own an ohm meter and can not easily check. In any case, it should be easy to try and see if the buffing problems disappear. Just a loose wire from a water line to the lathe.

[Bill ThompsonNM]

Glenn, thank you for taking time to think about my situation. I use the extra ground wire only while buffing. I wired the basement shop myself and there is always the possibility that I did something wrong. I do not own an ohm meter and can not easily check. In any case, it should be easy to try and see if the buffing problems disappear. Just a loose wire from a water line to the lathe.
And of course if anything was going to produce high static charges: Buffing would do it -- particularly in a dry space. Its a lot like a little van de graff generator.

[Richard Dooling]

That's an interesting idea. Jens, is your shop very low humidity? Have you ever had a static charge from the lathe "prick" you?

[Jens Bingel]

Richard, my shop is quite dry, especially during the winter months. No, I never got a little shock from a static discharge.