Thanks.. I'm not opposed to a bit o' tinkering.. much like overclocking, a true test would be to jack it up with all axis in motion until there is a fault or the table maxes out, then back it down someOriginally Posted by nicad
I would like to try to help you out as I have seen my rotary axis run much faster than this. Let me first say that changing settings in config files can cause your machine to not work properly and Tormach more than likely has reasons for doing things the way they do, but I am a tinkerer at heart and want to know details and the "behind the curtain" of the things I own. Backup anything before you open or change it.now, that being said-- Goto your folder C:\PCNC3 and look for a file named PCNC770M3.xml (I have the PCNC770, if you have the 1100 your file name might be something like PCNC1100M3.xml, I dunno). IE wants to open it to view, but you'll probably need to open in notepad to edit.
Look for the line:
<Vel3>21.67</Vel3>
Mine is 21.67 by default, What is yours? (I don't recall off hand what unit this value is in, but it directly relates to your DPM)
I have since upped it some. I haven't timed it, but it sure seems to be more than 1300 DPM.. more like 2000.
Note that I am running a Smoothstepper so I am not limited by the parallel port for step rate limitations. Tormach might have very well limited the rate to stay within the computer's parallel port speed, but that just seems painfully slow. The 21.67 value is default in mine, so you should at least be able to hit that value in yours.I won't go that far, but do want to at least reach the claimed speed. I'll check it out in a few min.. thanks for the tips.
** Edit **
Ok, here's my 5 minutes worth of testing and analysis based on what I know of how the control systems work.
> My Vel3 was also 21.67, but clearly not the right setting for the 8" table and 1800DPM.. do you have the 6" or 8" table?
> There is a mechanical speed limit of the stepper - Didn't test it to limit, but it will go pretty fast, and way faster than the rated limit.
> There is an electronic limit to how many pulses the Mach engine can deliver to all the various steppers at once, and the table takes lots of pulses - Didn't try to find that limit, and with this version of Mach, its hard to tell. I presume this is part of the max speed setting.
> Above 1800 DPM, there is a wide band of max speeds where there is an unwanted resonance at certain table speeds - I presume this is why they limit it to 1800. Just above this speed is where you start to see resonance at around 180dpm.
> Doing 20 or so experiments, you can either keep reducing or keep upping the maximum speed until the resonance goes away - I chose faster.
Thanks again for the info... The bigger brains with more free time here can do some formal analysis and find max speed, max pulse limit, safety factor and all that. Until then, I thank you for the tips, and I'm making rated speed on the rotary now. I'll continue to follow up with Tormach to get the back story.
Last edited by Spinnetti; 09-02-2012 at 01:43 PM.
** Update **
Tormach provided their usual good service and gave me a software update, which runs the table at listed speed. I'd never have noticed it was underspeed except that I tested it due to what was ultimately the dip switch settings being wrong.
All's well now, and enjoying the new toy....
Awesome!
Post vids. :-) I'm still on the fence about a 4th axis.
Well, if you need one, then can't do without it, but unless you have specific needs for it, I'd skip it. I wasn't able to machine x/a like I wanted. Ended up having to do x/y, index and repeat.. not ideal. Maybe I'll be able to after I optimize. Got some new coated carbide coming, so we'll see. I erm, sorta sped my table up a lot. IIRC, I set it around 2000 DPM and it will go faster yet, but individual results vary and gotta watch for resonance bands.....
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