LabView open PWM HELP
 

We are having problems with making our three motors all run up and down. As of right now we have three motors attached to our manipulator. All three motors will allow us to go down, but only one goes up. They are all supposed to be able to do both. Each motor has its own PWM and victor.

In an attempt to see if it was a mechanical problem we plugged each motor into each Victor and PWM and it still only worked on PWM 2, 1 and 3 still won't go up.

In the code, we swapped PWM1 and 2 and retested, now only PWM 1 worked. We took the one that was working and deleted the other two, copied the working one and changed the PWMs and the names to see if we just used an older version of the open motor vi. It still didn't work.

We swapped out all of the wires and digital side car and retested again and recieved the same results.

After that as a final attempt we plugged the two unworking PWMs into our drive PWMs and used the joystick rather than buttons to make the manipulator go up and down. It worked. But we would rather have the buttons and orginal PWMs working.

We know that it's not a problem with the buttons, our code, or electrical. The button works for the one working PWM and everything was swapped electrically and we still got the same results.

Any suggestions? Anyone having this same issue?

Re: LabView open PWM HELP
 

I still vote for a mixture of programming and electrical :)

I'd look at a single Victor at a time.
How are the Victor status lights behaving (green/red/off/orange or blinking)?

Re: LabView open PWM HELP
 

I agree with that. I'm thinking it'd be electrical.

Re: LabView open PWM HELP
 

They are behaving normally. It's not the victors we ruled that out completely.

Re: LabView open PWM HELP
 

We fixed the issue, what had happened was we put a disable structure on our previous code, and was using simpler basic code for testing in the area where we assign speed values. Turns out under that disable we had a control that disabled our ablility to drive, and disabling a disable made it have a mind freakout... yay labview for winning darwin award.

Re: LabView open PWM HELP
 

Since I don't know what a mind freakout for a programming language is, can you describe the issue again?

Greg McKaskle

Re: LabView open PWM HELP
 

Diagram disable
Programmers can temporarily remove code from a LabView VI. Placing the diagram-disable structure around the code will cause it to be "Commented-out".
Flipping the structure to its "enable" side will also allow the programmer to add new code as a temporary replacement for that removed. However, the real-time system has a problem with this structure. I discovered on a PXI chassis two years ago that the disable-structure does not work if it contains a front-panel item.
For example a boolean control on the front panel shows as a variable on the diagram. We accidentally included this variable in the disable-structure.
We then added new code that did not use this control. When running the code, the observed results of this VI were very strange. Data was not following the coded instructions of either the "enabled" or the "disabled" code. In addition, when we changed the enabled version slightly, the output changed in unexpected ways.
The workaround here is to use caution. Never include a front panel control inside the diagram-disable structure.

jerry

Re: LabView open PWM HELP
 

Very interesting. I'll try to reproduce it and file a bug report against the compiler. I've never seen this, but then again, I don't use the disable structure that often.

Greg McKaskle