Late to the party armed with nothing more than book smarts, may not be enough. If you can accurately measure time over distance, you should be able to find relatively close max accel. Once the time over distance is constant from point to point you go back and say 0 to 100 took 500mS and 14mm or whatever. Then you just do the math to find acceleration.
On Thu, Aug 27, 2015, 6:47 PM Dave Cole <linuxcncro...@gmail.com> wrote: > >>>If you set the max acceleration lower than > the actuator is capable of, I assume it will work fine and just take longer > to ramp up to full speed than it could in theory.<< > > Yes. It will work fine. You want the accel limit lower than less that > what it can actually do. Years after you set this up and things get a > little gummed up, > you don't want your actuator to be slower than what you command. That > may result in following errors and frustration. > > The same is true of the max velocity. > > Dave > > > > On 8/27/2015 6:15 PM, Jerry Scharf wrote: > > My question was the opposite. If you set the max acceleration lower than > > the actuator is capable of, I assume it will work fine and just take > longer > > to ramp up to full speed than it could in theory. > > > > jerry > > > > On Thu, Aug 27, 2015 at 1:50 PM, Karlsson & Wang < > > nicklas.karls...@karlssonwang.se> wrote: > > > >> If you try to accelerate the actuator above what the actuator is capable > >> of the best thing that could happen is it will not keep track of the > >> position and the other thing are more bad. > >> > >> > >> > >> > >> On Thu, 27 Aug 2015 11:35:04 -0700 > >> Jerry Scharf <jsch...@finsix.com> wrote: > >> > >>> Hi, > >>> > >>> One last question about this. Is there any harm in reducing the max > >>> acceleration below what the actuator is capable of? I wouldn't seem > like > >>> it, but I want to be sure. > >>> > >>> I know it will slow things down a bit, but this is by far the fastest > >> part > >>> of my system and only moving a short distance. > >>> > >>> jerry > >>> > >>> > >>> On Tue, Aug 25, 2015 at 5:04 PM, TJoseph Powderly <tjt...@gmail.com> > >> wrote: > >>>> Jerry I didnt answer your question. > >>>> to measure acceleration there's an industry standard 'step' test. > >>>> The 'step' is to apply the voltage required to achieve max velocity. > >>>> This voltage **instantly** rises from 0 to the value needed for max > >>>> velocity. > >>>> Thats where the name 'step' comes from, > >>>> Its a square edge on a scope. > >>>> > >>>> A second measurement is now needed, > >>>> Some way to determine _when_ the > >>>> maximum velocity is actually achieved. > >>>> > >>>> Old school dc motors gave us Tachos so this was easy. > >>>> I dont know what you can put together. > >>>> You could attach a voice coil to the end, I suppose. > >>>> Measure when the output voltage goes constant ( at max vel ) > >>>> A scope should show a 'knee' starting at 0Volts. > >>>> > >>>> But if you measure time from the 'step' until the max vel, > >>>> you have the precise acceleration _time_. > >>>> > >>>> The acceleration time divide by time is the acceleration > >>>> > >>>> ( example .240 Sec accel time to achieve 800mm/minute velocity > >>>> is .24 sec to achieve 13.333mm/sec > >>>> is 55.555 mm/s/s > >>>> > >>>> 3.15"/sec / 0.02ec = 157.5in/s/s ) > >>>> > >>>> HTH > >>>> TomP > >>>> tjtr33 > >>>> On 08/25/2015 04:09 PM, Jerry Scharf wrote: > >>>>> Hi, > >>>>> > >>>>> My quick scan of the docs didn't find an explanation for how to > >> calculate > >>>>> this from manufacturer specs rather than experimentation. I want to > >> make > >>>>> sure I am doing this right. > >>>>> > >>>>> The actuator is rated a 3.15 inches per second and it can reach full > >>>> speed > >>>>> in under .02s for the load I will be putting on it. If I use a = v/t, > >>>> this > >>>>> comes out to about 150 inches per second square. Does this look > >> right? > >>>>> The actuator is a SMC LXPB2BD-50S that I picked up used. > >>>>> > >>>>> jerry > >>>>> > >>>> > >>>> > >>>> > >> > ------------------------------------------------------------------------------ > >>>> _______________________________________________ > >>>> Emc-users mailing list > >>>> Emc-users@lists.sourceforge.net > >>>> https://lists.sourceforge.net/lists/listinfo/emc-users > >>>> > >>> > >>> > >>> -- > >>> Jerry Scharf > >>> FINsix IT > >>> 650.285.6361 w > >>> 650.279.7017 m > >>> > >> > ------------------------------------------------------------------------------ > >>> _______________________________________________ > >>> Emc-users mailing list > >>> Emc-users@lists.sourceforge.net > >>> https://lists.sourceforge.net/lists/listinfo/emc-users > >> > >> > ------------------------------------------------------------------------------ > >> _______________________________________________ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > >> > > > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
