How to disable drive upon LabView error

[Brian_Beal]

Buy a moton controller.  If Labview crashes, you lose all logic.  Don't close out Labview or abort your program.  Stop your program, and have it perform an orderly shutdown.

[Adam_H]

Hi All,

I agree with Brian.  It sounds like a motion controller would be a much better solution for you.  Like he said you need to ensure that the program closes correctly to keep your system working how you would expect.

[MarkMoss]

You might want to consider implementing a watchdog function in a CVM program running on the Copley Xenus drive.  I haven't tried this myself, but it seems like you could use the WaitForInput CVM function to detect when an input line to the drive holds the same state for more than a second or so and then either disable the drive or run some type of soft-stop routine.

Also, if your controlling position, you might want so see if there is a way for you to use your drive in analog position mode.  This way, your actuator should hold a constant position, rather than a constant torque/force, if the PID loop on the computer stops unexpectedly.

Mark Moss

Electrical Validation Engineer

GHSP

[Maciekdp]

I'm using the amp in force(current) mode in order to achieve simple impedance control.  The problem arises when labview crashes and the amp is power cycled.  Under gravity, the actuator shaft drops down, and then shots back up propelled by a force, which is proportional to the position error.  A coleague suggested that I use a PIC microcontroller in watchdog mode.  This should solve my problem very nicely.