> 1. direction changes are slow. No consequences when driven by the human > hand running a joystick on the side of the seat, but important for > computer control.
Typical delay for changing direction is 600microseconds. This is less than the typical LinuxCNC servo period of 1ms. The reason for this delay is probably due to the relatively slow switching speeds of the high-side mosfets, to eliminate shoot-through. If you plan to change motor directions no faster than the LinuxCNC servo thread, why is this too slow? This is too slow to drive the motor in "synchronous antiphase” or with a triangular waveform but I don’t get why you want to do that. But there are many things I don’t get. :) > 2. No evidence from the waveforms shown that the pwm is used for anything > but a logic clock. At no point in the waveforms shown starting on page > 13, is there any evidence of the pwm actually modulating the outA or > outB voltage in time with the input pwm. This is designed as an on/off > control only, and low standby current consumption in the very low > microamps was the prime specification driver. The boards I have ordered, > unless they are doing something that STM does not know or show, are not > capable of pwm driven analog control. As per the timing diagrams, the PWM input directly controls the low-side power mosfet with a 1.5 to 5 microsecond rise/fall time. _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
