On 2010-07-09, Karl Townsend wrote:

But how does the control tell the drive what speed to use, if the
drive is in torque mode?

I do not quite understand this.

i

The control is smart, the drive is dumb. The control only tells the drive
what to until the next refresh. The control looks at actual position vs.
command position, acceleration, etc. and makes a decision for how much
motion till the next refresh to solve the positioning problem. The dumb
drive just gets a voltage and does what its told.

In which case, it is possible for the computer acting as the
control to lock up (BSOD for Windows) just after issuing a command for
high torque, leaving the motor running quite rapidly until it hits a
stop.

Less likely to happen with the linux backed EMC, but still
possible if there is a hardware failure in the computer.

Enjoy,
DoN.

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