[nickcornilsen]

Hi,
Servo's are tuned up, a little feed-forward gain, I gain around .011, and the response looks great!

Now,

to control my spindle, I have an enabling relay driven by the relay driver outputs... and a DAC that sends an analog signal to the spindle drive to tell it what speed to run at. I can't just wire this relay "on", as it is what prevents my spindle draw-bar from opening if the spindle is turning.

To run CW @ 3500 (100% speed) I need to send a -10V signal to the drive.
To run CCW @ 3500, the signal would need to be +10V.

I can't seem to see how to set this up in the Kmotion screen. I also can't figure out how to pass the speed and direction to a user program. If I could pass the direction and speed to a user program, I'd have no problem getting this working. Is there a way to do this? I'm a bit confused about how to use the "Persist.UserData" to make this work.

Any ideas?

Thanks again!
-Nick

[TomKerekes]

Hi Nick,

Yes that becomes a bit tricky because the various commands S, M3, M4, M5 depend on each other and can come in various orders. So for example the S command can't immediately set the DAC even though it knows the speed because it doesn't know the direction yet (if the spindle was).

Please take a look at the \C Programs\SpindleUsingJogs example. That example is quite similar to your situation except it issues Jog commands to an axis to set the speed vs writing o a DAC. It maintains the previous state of things in 3 persist variables as described in the comments

// desired speed is passed in variable 1
// save in user variable 99 the last speed setting
// save in user variable 98 whether it was off, CW, or CCW (0,1,-1)
// save in user variable 97 the last desired speed

You will need to modify all 4 C programs for M3,M4,M5, and S.

Please try to modify those and if necessary post the changed files and we can help.

Regards

[nickcornilsen]

I think I've massaged the example programs to work. I just need to wait 'till this weekend to test it out!

By the way, floating point math isn't as intuitive as I'd thought... (IE, dividing 2047 by 3500 to get the DAC factor is NOT the same as multplying 2047.0/3500.0... one gives you zero, one gives you .584!

And, tom... please add some kind of indicator in the C programming screen in Kmotion that tells you what line you're on. As of now, if I have a programming error, I have to copy-paste the program in notepad to find the line the error is on... Or am I missing something?

[TomKerekes]

Hi Nick,

Heh heh. C can be tricky. With integers it does integer division

2047/3500 - zero + Remainder 2047

2047.0/3500.0 - 64-bit floating point numbers with ~17 digits of precision

2047.0f/3500.0f - 32-bit floating point which is about 2X faster but only ~7 digits precision.

But actually the compiler should reduce the value to a constant at compile time so no division is actually performed at run time.

When you have an error there should be a RED marker on the line of the error. Doesn't it show on your screen?

[nickcornilsen]

Hi Nick,

Heh heh. C can be tricky. With integers it does integer division

2047/3500 - zero + Remainder 2047

2047.0/3500.0 - 64-bit floating point numbers with ~17 digits of precision

2047.0f/3500.0f - 32-bit floating point which is about 2X faster but only ~7 digits precision.

But actually the compiler should reduce the value to a constant at compile time so no division is actually performed at run time.

When you have an error there should be a RED marker on the line of the error. Doesn't it show on your screen?

Typically I run the programs by hitting "init" on the KmotionCNC screen. (or by typing the relevant M code, etc) When I see an error there, I have nothing to cross-reference the line to, and I don't see that line in the C program editor. When I run it from the C program screen, I do get the red dot.

[TomKerekes]

Hi Nick,

If you have the program open in the C Programs Screen but don't want to Compile/Run it from there for some reason, then another option is to just push the "Compile" button and it should pop up the same compile error message and take you to the offending line.

Regards