DC Motor Control

[BME_genuis]

I need help in figuring out how to control my DC motor.  It is 1/4 HP @ 1725 RPM, 90V, 2.8A full scale.  I need around 200 in-lbs of torque for my application.  I have a SCXI-1124 and a motor controller.  To control speed I want to use a PID loop with feedback from a tachometer.

Thanks,

-Scott

[BME_genuis]

I need help in figuring out how to control my DC motor.  It is 1/4 HP @ 1725 RPM, 90V, 2.8A full scale.  I need around 200 in-lbs of torque for my application.  I have a SCXI-1124 and a motor controller.  To control speed I want to use a PID loop with feedback from a tachometer.

Thanks,

-Scott

[Brian_Beal]

You don't say what motor controller you have, but most DC motor controllers have tach inputs and will control the speed with their own PID loop.  Your 1124 can be used to send the controller a speed setpoint.

[Wes_P]

Hi Scott,

Typically motion control systems have a motion controller, a motor drive and a motor.  NI has motion controllers in the PCI and PXI form factor.  The controller card outputs logic to a motor drive, which supplies the power to the motor to be driven.  In your case, you would need a drive that can output a 90-V signal.  NI's servo drives output up to 24 V.  If you go to ni.com/motion, you can find some useful information for parts that would be needed to set up a motion system.

[Brian_Beal]

Let's get back to the basics of this.  Do you really need 200 in-lbs, or 200 in-oz.  To get 200 in-lbs of torque with that motor, you will need about a 24:1 gearbox.

[BME_genuis]

I do really need about 200 in-lbs of torque and thus I need a 30:1 gearbox with this motor.  My process signal is a 0 to 10 V input from 1124 to the motor controller.  How do I calculate my 1124 output volt range to get a certain RPM at the output of the gearbox and how do I configure this in Labview 5.1 or MAX?

-Scott

[Brian_Beal]

You still haven't told us anything about your motor controller, which is the most important piece of this puzzle.  They will typically have zero and span pots that scale the analog reference signal to the motor speed.  Watch out, as most of these pots are interactive.

[BME_genuis]

Check out the link for the drive:  http://www.reliance.com/prodserv/standriv/dc/dc2/index.htm (speed control model)

I am trying to figure out how to software-configure the analog output channel to the motor controller.  I will be using a 3 to 8 V input range to get a 10 to 40 RPM range on the output shaft of the gear reducer.

[Brian_Beal]

The link to the manual for that drive is dead.  

I have never configured those modules.  You may want to post that portion of your question on another hardware forum.

[BME_genuis]

Brian,

What do you mean it is dead?  Can you at least tell me how to configure that 1124 output channel in Labview 5.1?

Thanks a bunch.

-Scott