Jon Elson wrote: >>For speed: >>The max jog speed is set in emc to 90 ipm (1.5 in/sec). When jogging at >>the max rate I measured a step frequency of 813 Hz on phase A. >>Calculating the table speed: >>800 pulses/sec x 60 sec/min x .0004 in/step = 19.2 ipm >>However just by looking at the table move, it is moving much faster than >>that. >>Is this because due to the nature of quadrature drive, the table >>actually moves 4 times faster than the step rate? >> >> >Yes, precisely. Every change of either A or B is a "full step" >of the motor. 813 Hz should give 3252 steps/second, or 78 IPM. >I'm not sure why you aren't getting the full 90 IPM you are >requesting. > > > Well it's probably because of my halscope measurement. When using the fast thread for a halscope trigger, it retriggers when the buffer fills. Consequently when you stop the jog it begins decelerating and the buffer can fill and cause a retrigger during this phase. I tried to get around this problem by hitting "machine off" as I stopped jogging. So the reading I got in halscope I'm sure was probably during the beginning of the deceleration period.
Using a real analog scope I measured about 1 Khz. This calculates to 96 ipm. So at 90 ipm my scope reading should have indicated a period of 1.06 millisec => 938 Hz. This is within the accuracy of my reading the scope and its error. Jack Ensor ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
