Stepper Motor: Closed loop PID

[Highland_Controls]

I would think that a velocity(and direction) command for the blade angles would work best.  You are really closing the PID loop with the rotational frequency feedback.  The cRIO is really a computer.  If you are using a cRIO, then the PC becomes mostly a dumb HMI, unless you are logging lots of data.  If you dont' need the ruggedness and reliability of the cRIO, then this could all be done on a PC. Since you are using incremental encoders, you will have to have some kind of homing routine.  Are there provisions for limit switches for the blade angle?  If I were doing this from scratch, I would probably find a stepper driver that can just follow a +/-10VDC signal in velocity mode(often called direct drive mode), and that can use limit switches.  I think you mean your stepper drive takes a PFM signal, not a PWM signal.  So in short, if you are doing closed-loop position moves, then you need a motion controller.  Doing motion control on the cRIO isn't trivial.  Doing motion control, in general, isn't trivial either.  If you are just sending velocity commands to the stepper drives, then there is no need for a motion controller.

[JoLe]

Hi Jack,

for your issue on what kind of HW setup is best for my application / assignment you could directly contact NI and talk to a technical sales representative.

It's exactly their job to consult and support you with this decision.

ni.com/contact

Best Regards,

JoLe

National Instruments

Applications Engineering

www.ni.com/support

[Sami88]

Hi,

I have a 2-phase hybrid stepper motor (+encoder) in closed loop for position control of a ball screw drive.

I have the following hardware for my setup.

-NI - cRIO-9024

-NI - 9501 (for contorlling the motor)

-NI - 9411 (Encoder)

I have been wondering if anyone can provide insights about PID control of the stepper motor with the above hardware.

Thanks in advance,

Sami