> Greetings; > > I can do 48.7 IPM all day, either direction, but one cliock faster on the > jog speed, to 51 IPM and I have a following error in about 3/8" of > movement, independant of the direction. Next step up on the slider is > about 53.x IPM, gives a following error in about 3/16" of motion. > > The step timings are: > dir preset 6000 > Step_len 3000 > Step_space 3000 > dir hold, 6000 > > Worst case, 18 u-s to do a dir reverse and one step then revert the dir. > 12 u-s for dir_setup+dir_hold, and 6 more for the step=18. > > Grabbing a copy of kcalc, enter 18 as .000018, do a 1/x to get the max > freq=55,555.5555555555556 or a but over 55 kilohertz. Drive claims it > can do 200 kilohertz. driver is set for /8 microsrepping. Screw is a > 16x5mm. > > So how fast can it go when the pulses are at 200 KHz? > > FWIW, this tripping of the following error was taking place at the exact > same speed ( give or take a couple percent ) with the previous driver & > motor which was set for a /64, and the same step timeings and this one > is set /8, so no way can I convince myself the problem is the maximum > step rate the 5i25's stepgen can do, or that the driver can eat and be > happy. > > I have fiddled with the ini files maxvels, and maxaccels, without a > measureable effect. > > So where is the next place to look for my following error, which FWIW, is > at 48.7 IPM nothing but noise with the exponent never dropping below > +-EE-06 but mostly in the +-EE-12 range?
I would guess some lag problem. I am pretty sure I got following errors for stepper motor although for this following is exactly correct in the software. There is no encoder so real motor might of course miss step. Then using step with a scale of 1000 which fit with number of decimal places I also got an offset of one step at least in some circumstances. I use slightly modified hostmot driver and protocol send step position instead of step velocity. Nicklas Karlsson ------------------------------------------------------------------------------ Find and fix application performance issues faster with Applications Manager Applications Manager provides deep performance insights into multiple tiers of your business applications. It resolves application problems quickly and reduces your MTTR. Get your free trial! https://ad.doubleclick.net/ddm/clk/302982198;130105516;z _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
