My mill seems to be working OK, with decent speeds and feeds - though I'm getting intermittent missed steps on the fast rapids. I'm still kind of fixated on making these motors do their best - maybe I'm just tilting at windmills, who knows.
I just located some specs on what I believe to be the motor and control setup on my mill. It appears to be a Vexta PH266 series motor with Thompson L6203 driver chips. I don't know exactly what I am looking at here and if or how these values combine into what EMC needs to optimize step length and timing. From the chip spec sheet: LOGIC CONTROL TO POWER DRIVE TIMING Symbol Parameter Test Conditions Min. Typ. Max. Unit Source Current Turn-off Delay 300 ns Source Current Fall Time 200 ns Source Current Turn-on Delay 400 ns Source Current Rise Time 200 ns Sink Current Turn-off Delay 300 ns Sink Current Fall Time 200 ns Sink Current Turn-on Delay 400 ns Sink Current Rise Time 200 ns Motor Spec: (though this probably doesn't matter as much for step generation?) Maximum torque:6kgcm Current: 0.6A/phase Voltage: 12 V Resistance: 20 ohm/phase Rotor inertial moment :135gcm2 Does this help in deciding on the "correct" values to plug in to EMC? Thanks, - Michael On May 6, 2009, at 9:59 PM, Michael Jones wrote: > My problem? I don't know what I'm doing. I need some help. > > I have a D&M4s mini mill that a friend and I have refurbished into > full parallel control with a board from Campbell Designs. Works > pretty well, but I'm seeing some idiosyncrasies with the current > setup. > > It runs what looks like a Sherline mini mill with an older style (not > atlas) stepper motors.. (they're in a round case, and have no markings > except for the D&M label that has no information on it). The stepper > controller boards are L297/8 chopper driver boards. I'm thinking of > upgrading the steppers at some point to something with a bit more > torque/speed but that'll have to come later. > > I've been reading in parts of the documentation and troubleshooting > pages that some of these issues could be due to step length and such > being set up incorrectly. > > Is anyone else working this (or a similar) setup? > > 1) Here's the axis information from the .ini file: > > [AXIS_0] > TYPE = LINEAR > HOME = 0.25 > MAX_VELOCITY = 0.15 > MAX_ACCELERATION = 0.5 > STEPGEN_MAXACCEL = 1.250 > SCALE = 8000.0 > FERROR = 0.05 > MIN_FERROR = 0.01 > MIN_LIMIT = 0.0 > MAX_LIMIT = 7.325 > HOME_OFFSET = 7.325000 > HOME_SEARCH_VEL = 0.075000 > HOME_LATCH_VEL = 0.062500 > HOME_IGNORE_LIMITS = YES > HOME_SEQUENCE = 1 > BACKLASH = 0.008 > > [AXIS_1] > TYPE = LINEAR > HOME = 0.25 > MAX_VELOCITY = 0.15 > MAX_ACCELERATION = 0.5 > STEPGEN_MAXACCEL = 1.250 > SCALE = -8000.0 > FERROR = 0.05 > MIN_FERROR = 0.01 > MIN_LIMIT = 0.0 > MAX_LIMIT = 4 > HOME_OFFSET = 3.950000 > HOME_SEARCH_VEL = 0.100000 > HOME_LATCH_VEL = -0.062500 > HOME_IGNORE_LIMITS = YES > HOME_SEQUENCE = 2 > BACKLASH = 0.0075 > > [AXIS_2] > TYPE = LINEAR > HOME = -0.25 > MAX_VELOCITY = 0.10 > MAX_ACCELERATION = 0.4 > STEPGEN_MAXACCEL = 1.25 > SCALE = 8001.0 > FERROR = 0.05 > MIN_FERROR = 0.01 > MIN_LIMIT = -7.0 > MAX_LIMIT = 0.0 > HOME_OFFSET = 0.000000 > HOME_SEARCH_VEL = 0.100000 > HOME_LATCH_VEL = 0.062500 > HOME_IGNORE_LIMITS = YES > HOME_SEQUENCE = 0 > BACKLASH = 0.011 > > Do these numbers look normal? The MAX_VELOCITY and MAX_ACCELERATION > look strange to me.. but then I don't know what normal is.. > > The backlash is a little high - it's on the list.. but otherwise what > should I be looking for here as "normal". > > 2) I seem to be having some issues with my Z axis loosing steps (X and > Y seem to be pretty stable). When making a series of up and down > moves for some engraving, the depth gets reduced as the program > progresses. > > 3) Is the step generation dependent on the stepper motor driver, or > the stepper motor itself? > > > Any advice or pointers to any good resources would be greatly > appreciated. Remember.. I'm a NOOB at this, detailed explanations > would be GREATLY appreciated. > > Thanks > > - Michael > > > ------------------------------------------------------------------------------ > The NEW KODAK i700 Series Scanners deliver under ANY circumstances! > Your > production scanning environment may not be a perfect world - but > thanks to > Kodak, there's a perfect scanner to get the job done! With the NEW > KODAK i700 > Series Scanner you'll get full speed at 300 dpi even with all image > processing features enabled. http://p.sf.net/sfu/kodak-com > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
