>
>
> Ok, I took a look at the voltage coming from the OOPic at various speed
> settings. The voltage dropped steadily down to below 1V on the
analog meter
> at a value around 70.
So, presumably, the OOPic is producing a variable width pulse. That's
good...
>
> However, I also went looking at the motor specs. The no load draw is
300 mA,
> but the max draw at shaft lockup is 2A. I would have thought there
was less
> current draw at lower voltage, but I may be getting that wrong. In any
> event, the 1A limit is being doubled.
Sure, there will be lower current at lower voltage but it may not be
enough to rotate the motor. At some point the voltage/current is
sufficient to spin the motor and at that point the current may be too
much for the driver.
If your meter will measure current of a suitable range, connect it in
series with one of the motor leads and see what you get. If it tries
to exceed 1A, the driver chip should shut down. If you have a second
meter, you might try to measure the voltage at the same time.
The thing is, if the chip shuts down, I expect it to stop after a
short delay while it heats up. It is a thermal shutdown, not an
actual overcurrent shutdown. Or, at least that's what the datasheet
implies.
Remove the oDCMotor2 object and set the IOLines directly. When IOLine
17 (or 18) is set to '1' and the other two lines are in opposite
states, the motor should run full speed.
Touch the chip while the motor is running and see if it is getting hot.
Richard
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