Driving Motors by Tachometer Counts

[vmaddur]

On the AnalyticPhysics page for the assembly (see here), it states that when driving motors by tachometer counts you pause program execution using OUTPUT_READY. However, it also states that in practice this often pauses the program indefinitely, so we work around this by using an additional timer. Do the wait statements from the timer come before or after the OUTPUT_READY statement? It would be helpful if you could provide a sample assembly sequence using OUTPUT_STEP_POWER or OUTPUT_STEP_SPEED with the timer.

[vmaddur]

The way I currently understand it, we could do something like this:

TIMER_WAIT(time up+time run+time down+C,timer)
OUTPUT_TIME_POWER(layer,motors,power,time up,time run,time down,brake)
TIMER_READY(timer)

for some small positive constant C (accounting for minor deviations) for timing the execution of time-based motor movements. However, I do not see a way to modify this for tachometer counts (based on rotations not timings).

[dlech]

As far as I know, OUTPUT_READY will only block indefinitely if the motor is physically obstructed from reaching its target. OUTPUT_TIME_POWER should not need an extra timer since it depends only on time already.

To avoid blocking calls, I suspect OUTPUT_TEST could be used instead of OUTPUT_READY to test if the motor has reached its target. OUTPUT_READ could also probably be used to implement some sort of stall detection (e.g if speed from OUTPUT_READY is 0 for 1 second and OUTPUT_TEST is still busy, then the motor must be stalled).