05-09-2012 03:26 AM - edited 05-09-2012 03:28 AM
I am an ME graduate student doing wind tunnel testing. I need to control motorized stage holding a probe in our wind-tunnel for the last step of my project.
I am trying to use the 6009 USB DAQ to control a stepper motor and simultaneously (keep it simple for now) acquire differential voltage data from 3 different sources. I have done some of the basic LabVIEW tutorials and the analog side is working properly from simple testing in MAX.
I am sort of lost on where to begin. I have done a lot of searching around on the discussion boards but everything seems overly complicated for my purposes.
My stepper motor drives a single Velmex stage (http://www.velmex.com/motor_15.html). It was hooked up to a controller that uses an AC adapter. This particular controller is too old to be found online. A switch box with pushable buttons to control STEP and DIR was connected to the controller with 3 wires. Pretty sure there was a 3rd physical button but I cannot remember right now.
I disconnected the 3 wires between the switchbox and the controller, and now I plan to connect the motor controller's 3 wires into the digital outputs of the 6009. I am pretty lost on what type of signal(s) (i.e. frequency and amplitude) to output from the DAQ into the 3 inputs on the controller. I do not have any documentation on this controller.
It would be nice to push a button on the Front Panel window, carefully raise the stage up one-tenth of a millimeter, click a button to record data for 20 seconds on all analog channels, then repeat for 10-20 increments.
Thank you so much for anything. I assume this would not be possible in MAX.
05-10-2012 10:37 AM
It's possible that the inpunt signal to the controller is a square wave with a maximum voltage equal to the
Vcc (reference voltage of the push button). My first advice to you is to measure the output signal of the
push button with a multimeter and identify the characteristics of the signal.
When you have that you can try to simulate that signal fro LabVIEW.
This can't be done on MAX.
05-10-2012 01:22 PM
I actually got the stepper motor functioning one step at a time in MAX using a single digital output line. I belive this is using something called TTL. If I add a channel to the task I am also able to control direction.
I brought this task into labview and made a small program that should run the stepper motor, but I believe there is something wrong with the DAQmx task that I am selecting.
I have a DAQmx Write function that supposedly writes one digital output line to true, waits 5 ms in a sequence loop, then writes the same digital output line to false. These 2 DAQmx Write functions are connected to the task configured for a single line digital output from 1 pin the 6009.
Appreciate any feedback.
05-10-2012 02:05 PM
You can do it on MAX but this is very limited.
Stepper motors can be used with fixed voltage (constant value)
If you can find the model of your stepper motor then you can find the datasheet and
check what voltage or input signal is requiered to driver the stepper motor.
You can aldo this example that describes how you can use DAQmx to drive a stepper motor.