[vonnieda]

I have mine sety up with steppers. Yes I use BLC when I need to do drilling or squaring metal. I found it leaves a stepped surface when using ot on radius cutting.

The reason I ask these questions when you have the BLC working it almost instantly (at least on my setup) compensates for backlash and doesn't use the acceleration until the backlash it made up for and the table on the verge of binding would surely bind if your backlash settings are off a bit. So if all is ok there I can't help you any further since this is the only thing I've experienced that is somewhat similar to your problem. Good luck I hope you get it going soon. Keep us informed.

Rick

Thanks for the information Rick. I didn't realize BLC didn't use the accel profile, although that makes total sense. I will pull my steppers off and double check the table. Is there anything I need to check aside from just finger turning the screws in each direction?

[vonnieda]

I just took a quick look at the 201's manual(actually it said 201A), to familiarize myself a little more with your hardware. I'm not familiar at all with the Dan M. hardware you have. Maybe you could post a few pics(both inside and out, would be helpful) of your controller/P.S. in order to get a more exact idea of what you are working with. But anyway, where is the 5v at pin 10(201's) derived from, and what does this voltage read? Since you have a scope you should be able to look at the dir., step, and 5v inputs at the driver itself(be sure and use the ground there as well). look for proper waveshape(square), and amplitude, with the 36v main disconnected from your drives(compare with and without blc). Then check it all again with the 36v connected along with your motors now running, both properly, and also exhibiting their faulty behavior. Pay particular attention to any level of noise that may now be present on those 3 lines. Also, do you have easy access to another computer? That would be a fairly straightforward way to eliminate about half of the possibilities for the source of your problems.

Clint

The 5v is coming from the computer's USB port via a USB "power cord". The 5v there is metering as 5.02v and I checked it with my scope and it's nice and clean.

Unfortunately the rest of my computers are all laptops without parallel ports, so I can't switch out very easily. I've been thinking about getting a Smoothstepper, though, so that would remove a lot of these variables.

I'll run all the scope tests you outlined tonight and report back. Thanks for taking the time to offer suggestions.

Jason

[escott76]

Thanks for the information Rick. I didn't realize BLC didn't use the accel profile, although that makes total sense. I will pull my steppers off and double check the table. Is there anything I need to check aside from just finger turning the screws in each direction?

If that makes "total sense" then your question should already be answered, no need to go chasing voltages. The simple fact is that if the backlash comp doesn't use the accell profiles, and tries to accelerate the screw (it's still mass, and it's still subject to causing issues with motor missing steps) too fast, you'll lose steps. If you can't get backlash comp to work over 15 IPM, but you can get reliable although backlash prone operation at higher speeds with it turned off, that is the limiting factor, not a parallel port voltage issue.

[vonnieda]

If that makes "total sense" then your question should already be answered, no need to go chasing voltages. The simple fact is that if the backlash comp doesn't use the accell profiles, and tries to accelerate the screw (it's still mass, and it's still subject to causing issues with motor missing steps) too fast, you'll lose steps. If you can't get backlash comp to work over 15 IPM, but you can get reliable although backlash prone operation at higher speeds with it turned off, that is the limiting factor, not a parallel port voltage issue.

What I meant when I said it makes total sense is that the BLC doesn't use the accel profile. Not that it explains the issue I am having. I still don't think my table is binding, but if more experienced people than I think it's worth checking, then I will check it.

The reason I don't think it's that is that the stepper doesn't just miss steps, it seizes. Even if the BLC caused it to miss several steps under full acceleration, when the acceleration of 2 kicked in the axis should start to move. It doesn't, as the video shows. Since Mach3 has no way of telling if the stepper has missed steps it should (under this theory) miss the steps required to do the BLC and then work fine for normal axis movement, but it doesn't.

I tend to agree with you. I don't think it's voltage or noise or anything electrical, and I also don't think it's physical. I think it's a software issue. That said, I believe it's useful to check "just to be sure" too cause I just don't know.

As for my question being answered; it's still not. If I can't use BLC above 15 IPM I'd like to know why. If it's a limitation of my controller, or steppers, or mill, or anything else I'll consider upgrading.

[escott76]

What I meant when I said it makes total sense is that the BLC doesn't use the accel profile. Not that it explains the issue I am having. I still don't think my table is binding, but if more experienced people than I think it's worth checking, then I will check it.

The reason I don't think it's that is that the stepper doesn't just miss steps, it seizes. Even if the BLC caused it to miss several steps under full acceleration, when the acceleration of 2 kicked in the axis should start to move. It doesn't, as the video shows. Since Mach3 has no way of telling if the stepper has missed steps it should (under this theory) miss the steps required to do the BLC and then work fine for normal axis movement, but it doesn't.

I tend to agree with you. I don't think it's voltage or noise or anything electrical, and I also don't think it's physical. I think it's a software issue. That said, I believe it's useful to check "just to be sure" too cause I just don't know.

As for my question being answered; it's still not. If I can't use BLC above 15 IPM I'd like to know why. If it's a limitation of my controller, or steppers, or mill, or anything else I'll consider upgrading.

For whatever it's worth I seem to recall the smooth stepper having issues with BLC as well. I'd check before dropping the coin.
Personally I prefer to physically eliminate all the lash I can, and go with no comp. I have double ball nuts on all 3 axis, with no measurable lash. BLC has always seemed a little hacky to me, and I've read a number of reports of people having issues with it. Is this an option for you?

[xy_eezy]

I just ran a 2'' circle contour at 10 continuous repetitions, at 70ipm. Once with blc off, and once with it on. Both runs were virtually identical, no problems whatsoever.
my settings are as follows:
Blc y .0266
blc x .003
backlash speed 80%
shuttle accel. .005 seconds

If you can't beat 15ipm, then trust me, you definitely have something out of sorts(or possibly need some better parts). I was under the impression that your setup was already working well at higher speeds, and only a couple of days ago, it had begun acting up. Did you not have the backlash set, prior to when you noticed you had issues?

[vonnieda]

I just ran a 2'' circle contour at 10 continuous repetitions, at 70ipm. Once with blc off, and once with it on. Both runs were virtually identical, no problems whatsoever.
my settings are as follows:
Blc y .0266
blc x .003
backlash speed 80%
shuttle accel. .005 seconds

If you can't beat 15ipm, then trust me, you definitely have something out of sorts(or possibly need some better parts). I was under the impression that your setup was already working well at higher speeds, and only a couple of days ago, it had begun acting up. Did you not have the backlash set, prior to when you noticed you had issues?

Thanks for running that test. It's good info to have. Are you running a stepper based system?

I have had backlash set since I got the mill but I had only been doing runs of 12 IPM or less. I have only recently tried to go higher to speed up operations at a smaller DOC on the advice of another forum member in another thread.

[SCzEngrgGroup]

For whatever it's worth I seem to recall the smooth stepper having issues with BLC as well. I'd check before dropping the coin.
Personally I prefer to physically eliminate all the lash I can, and go with no comp. I have double ball nuts on all 3 axis, with no measurable lash. BLC has always seemed a little hacky to me, and I've read a number of reports of people having issues with it. Is this an option for you?

The SmoothStepper does not currently support BLC at all.

Regards,
Ray L.

[xy_eezy]

Yes, I'm running steppers. Currently using Keling drivers(kl-6050), and an Astec 48v/25a supply. By the way I just ran the same test successfully at 100ipm.

[HackMax]

Thanks for the information Rick. I didn't realize BLC didn't use the accel profile, although that makes total sense. I will pull my steppers off and double check the table. Is there anything I need to check aside from just finger turning the screws in each direction?

Not really any need to check anything more in the binding area if you have access to and can turn the screws by hand if they turn freely with no power to the steppers you should be ok there. I saw in a post (and I forgot it was there:withstupi) the backlash speed. Have you tried to mess with it? Also I see you have a switching power supply. I hate those things. Most people have not one issue with them but I can never trust something that needs so much current to one of those types. Just a feeling I get from being an electronics tech for 25+ years. I use the unregulated type. I have the 6050s too and haven't had any problems with them. Also my mill never skips a step - if it skips it stalls and doesnt recover until it switches direction if that helps any. I like it that way cuz then I know my part is f@$k!d and I can stop it right there.

Rick

[vonnieda]

Just to follow up on this thread: I asked for some help in the Mach 3 forums and someone told me to try quite a few different settings. Last night I spent a bunch of time adjusting every setting I could find. The one that finally did the trick was the shuttle setting. I am not sure what I originally had it set to. The default, probably. Then the other day I changed it to .005 based on Hoss' video. The setting that fixed my problem was .05.

After setting that value I can now jog and cut at 35 IPM no problem, and I tested at 50 IPM and that worked fine too.

Thanks for all the help everyone. I appreciate you taking your time to answer my questions and make suggestions!

Thanks,
Jason

[xy_eezy]

Just to follow up on this thread: I asked for some help in the Mach 3 forums and someone told me to try quite a few different settings. Last night I spent a bunch of time adjusting every setting I could find. The one that finally did the trick was the shuttle setting. I am not sure what I originally had it set to. The default, probably. Then the other day I changed it to .005 based on Hoss' video. The setting that fixed my problem was .05.

After setting that value I can now jog and cut at 35 IPM no problem, and I tested at 50 IPM and that worked fine too.

Thanks for all the help everyone. I appreciate you taking your time to answer my questions and make suggestions!

Thanks,
Jason

Way to go! Glad you got it all ironed out.
Take care, Clint