874xMotorDriver: only one motor on a controller can move at a time

[kmpeters]

Only one motor on an 8742 controller can move at a time. Is this a limitation of the controller or the 874xMotorDriver?

[kmpeters]

The "Picomotor Interfaces" section (3.5.5) of the 8742 series user manual states, emphasis mine:

Each 8742 can drive up to 4 Picomotors, one motor at a time.

The move method should be modified to return an error if another motor is already moving.

[kmpeters]

The documentation for the PA command says that it should result in a "MOTION IN PROGRESS" error message. There is no check for the error after the move command is sent:

motorNewFocus/newFocusApp/src/874xMotorDriver.cpp

Line 291 in e146427

status = pC_->writeController();

The poller also doesn't check for errors.