On Wednesday 26 February 2014 15:29:32 a k did opine: > Hi > i have stepper motor from Keling Technology KL23H2100-35-4b > and Microstep Driver kl5056 > question: if i add to that stepper motor shaft encoder like > http://www.ebay.com/itm/400P-R-incremental-rotary-encoder-400-pulses-MAX > -mechanical-speed-of-1000-/330952664057?pt=LH_DefaultDomain_0&hash=item4 > d0e50e3f9 > Link is a blank page in my busted FF27.
> will that motor will become closed loop and can be considered as a > servomotor? That is generally a no, unless the stepper is running in idle mode. The problem is the negative torque curve of the stepper vs its speeds, meaning that if it slips a cog, it will be stopped as its in-capable of resuming the speed it was moving at when it failed by re-accelerating to that speed in a single step. All the feedback obtained from the encoder can do is attempt to speed it up to catch up, and its not capable of that while under the load that caused it to slip that cog in the first place. The best you can do with the encoders feedback is to use its error should the motor slip, to exert the fastest possible e-stop and hopefully save the part. If the part isn't damaged, then you'll need to rehome the machine and re-start the operation, running at a slower rate by sliding the feedrate knob to slower as that portion of the operation is being re- approached, hoping it will get thru the hard cut the next time. That said, I think there have been some attempts to use it, and you will find some discussion of it in the wiki. I have read it myself several times without fully understanding how it was used to dynamically rehome the slipped axis to get it back in step even after slowing the rest of the machine so it might be able to catch up with the rest of the machine now running slower. To me it seemed like a lot of expense and complexity for a limited CYA gain. Far better off to slow the operation to within the steppers abilities and/or raise the voltage on the drivers so the torque falloff is not as pronounced. I was nicely amazed by the speeds I could get out of my lathe, whose motors are running on around 37 volts, compared to the same motor and driver on my mill but running at 28 volts. A finicky 30 ipm on the mill, vs a rock solid 60 ipm on the lathe just by going up 9 volts. A side effect of the higher voltage on that particular driver, a 2M542 from fleabay at around a $50 bill a copy, is that this driver runs cooler at the higher voltage. But look it up on the wiki & make up your own mind. I'm just the resident retired old fart. ;-) > question: what is benefit of using dynamic encoder - like i have - from > servodynamics in compare stepper motor with + encoder that i found on > e-bay ? > i mean tangible benefit for cnc machine tool > > thanks > aram > > On Wed, Feb 26, 2014 at 1:28 AM, andy pugh <[email protected]> wrote: > > On 26 February 2014 06:11, a k <[email protected]> wrote: > > > my question is can i use on one system 3 ac servomotors and 2 > > > stepper motors? > > > > Yes, there is absolutely no reason why not. > > (Your extra axes would conventionally be U and V rather than A and B) > > > > -- > > atp > > If you can't fix it, you don't own it. > > http://www.ifixit.com/Manifesto > > > > > > ---------------------------------------------------------------------- > > -------- Flow-based real-time traffic analytics software. Cisco > > certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with > > NetFlow Analyzer Customize your own dashboards, set traffic alerts > > and generate reports. Network behavioral analysis & security > > monitoring. All-in-one tool. > > > > http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg. > > clktrk _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------ > ------ Flow-based real-time traffic analytics software. Cisco certified > tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow > Analyzer Customize your own dashboards, set traffic alerts and generate > reports. Network behavioral analysis & security monitoring. All-in-one > tool. > http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.c > lktrk _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> NOTICE: Will pay 100 USD for an HP-4815A defective but complete probe assembly. ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. Cisco certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer Customize your own dashboards, set traffic alerts and generate reports. Network behavioral analysis & security monitoring. All-in-one tool. http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
