0-10v Servo Control with 7i76E

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9 years 4 months ago #94556 by bymccoy
Thanks Andy

Sounds ideal, means I can drive the forward/reverse signals separately to the enable, plus it fixes the -10-0-10 signal for 0-10...

Perfect!

I've hooked it up with the PID feeding rbe spinout and it was a bit bizzare, but this should fix it!

Now just have to fix a strange issue with the encoders (now firmware updated and multiple encoders available, none seem to work), so getting broken/non-following joint errors.

Think I'll build a dirt simple UI hooked directly to HAL to test each sub function.

Thanks
Jon

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4 years 7 months ago #237294 by besriworld
Hi, I bought a 7i76e many years ago. Now I install it in a lathe. But I have a problem. I want the spindle motor to work as a servo motor, but the driver has no input for step direction. The analog output is very slow for a servo pid regulator. Can I add a fast analog output? How can I make an output like 7i77. Has anyone done something like this?

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4 years 7 months ago #237297 by bymccoy
I used a 7i77E, and setup PID on the spindle 0-10V output for this reason. The machine also interlocked two axis and used the same VSD, so with some control logic in place, there are two PID controlling a single output, and take it in turns to position. Not suitable for your application.

Maybe get a daughter card with a servo output in it (not sure what MESA has without looking, but you could always get a 7i77 and run as a daughter off the 7i76E).

Another option is to use the RS-455 interface with a compatible servo controller?

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4 years 7 months ago #237312 by andypugh

Hi, I bought a 7i76e many years ago. Now I install it in a lathe. But I have a problem. I want the spindle motor to work as a servo motor, but the driver has no input for step direction. The analog output is very slow for a servo pid regulator. 
 
The 7i76 analogue output is a digital potentiometer. It should update instantly every 1mS. 

What makes you think that it is slow? Is it possible that the slowness is in your PID tuning? 

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4 years 7 months ago #237357 by PCW
Replied by PCW on topic 0-10v Servo Control with 7i76E
A 7I83 (6 channel +-10V analog out SSerial connected)
is an option (though a bit overkill with 6 channels)

The 7I76E analog output is not terribly fast as it's intended
for normal spindle control and the isolation limits the PWM
frequency and thus filter bandwidth.

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4 years 7 months ago #237367 by besriworld
is it possible to make a small board that converts frequency into voltage.
My idea is to load 7i76e_7i76x1_7i77x1D firmware and just make a small board to add 1 fast analog output. But I don't know if this is possible and did anyone do it?
It just takes a long time to buy a new card.

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