07-25-2010 07:13 AM
I am brand new to Labview and have not had any training other than youtube and this fine forum. I am a mechanic trying to solve a problem using labview. I am posting this new question because I don’t have any hardware so I can’t use the examples I’ve seen others pointing to.
I’m trying to simulate the output of a quadrature rotary encoder. Once I have done that I want to use Labview to program an instrument that reads that signal and makes mathematical calculations to it but I need the signal first. The encoder will attach to a shaft that will rotate clockwise and then counterclockwise at a rate of about 122 times a minute. The total shaft rotation will be between 0 - 18 degrees. It is important to me to know the direction of the shaft. The quadrature encoder will send out 2 square waves with one wave behind the other. The way I’ve tried to do this is by using 2 Simulate Signal modules each sending out a square wave at 2 Hz. I’ve connected a single knob controller to the both frequency inputs of the signal modules to simulate the speed the shaft rotates back and forth. I’ve done the exact same thing to the amplitude input to simulate the degrees the shaft turns before changing directions. My problem is the changing directions. I can delay the phase, which is what I want to do, but I can’t do it in real time and I can’t do it in a single 180 degree step. What I would like is a switch to change the B channel from +90 to -90 when it is toggled. If I could then toggle the switch when the amplitude reaches 18 degrees or less I will have an encoder signal. Thanks for any help you can provide.
steve
07-26-2010 07:43 PM
Steve,
From what I understand, you want to make a 180 degree phase shift every N intervals? I modified your code to do this. Let me know if that gets at what you are doing.
Cheers,
Chris LS
07-27-2010 05:34 PM
Thanks Chris!
Not only did you solve my problem but you also added a couple things that I will need; adjustable switch point and a cycle counter. You also introduced me to a few new tools I must learn to use.
steve