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Old March 6th, 2004, 10:13 PM   #1
elevmike
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Drive control question?

I picked this post up from another forum:

"I'm trying to control a GE drive with a pulse output from the H2-CTRIO module. I've got it configured as CW/CCW, with the outputs into the +A and +B of the auxiliary encoder inputs of the drive, with the common of the drive on CO and C1, but it is extremely erratic and unrepeatable. I think my wiring is wrong, but there are no decent examples in the H2-CTRIO manual. Please help. "

I've never heard of this type of drive control. Am I misunderstanding the question? or is this guy trying to control the drive by inputting to the encoder feedback on the drive? Maybe somebody smarter then me can figure this one out.

Mike.
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Old March 7th, 2004, 06:46 AM   #2
DickDV
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While I am not familiar with the GE terminology mentioned in this post, it does sound like the drive speed is being controlled by a pulse train rather than an analog signal.

This kind of speed reference is not common but is very handy for applications like lead/follower drives where the follower is looking at an encoder on the machine. Precise speed control is possible and the system is somewhat less sensitive to electrical noise.

I've never needed to use pulse train speed reference and would try to avoid it because it is somewhat more difficult to troubleshoot.
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Old March 7th, 2004, 09:20 AM   #3
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It also looks like the guy is trying to feed the pulse train signals into the drive's auxillary encoder input. As long as both are 5VDC signals, it will not damage anything. However, CW/CCW pulse train is not exactly the "A/B quad" signal any encoder input would expect. No wonder, the operation is "erratic and unrepeatable".
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Old March 7th, 2004, 02:33 PM   #4
DickDV
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Mike, after further thought on this, I think it would be helpful to have access to the GE instruction manual for the drive, particularly the part showing the pulse train inputs and the software to set it up.

I gather that the pulse transmitter is an AB device. Eventually, we may need some specifics on that, too.
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Old March 7th, 2004, 05:26 PM   #5
elevmike
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Dick,

I picked up the question from another fo4um. I am totally unfamillar with the drive & application etc.. I reposted it here because I thought someone else, (you in mind), may have heard of this type of application. I now think the origornaor is attempting to control the drive by pulsing the encoder feedback on a "closed loop" system thinking that he could use it for a speed reference. It is my impression that he misunderstands the purpose of the aux encoder inputs on the drive, however I wasnt entirely sure as new stuff comes out all the time, and I'm not one to read every mailer I get. The more I think about it the more I am sure of my presumption.

Mike
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Old March 8th, 2004, 08:16 AM   #6
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As it turns out the origional poster is talking about a servo drive, not an AC drive. Anyway, I suggested this forum to him. So be on the look out.

Mike
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Old March 8th, 2004, 08:44 AM   #7
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test
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Old March 8th, 2004, 08:53 AM   #8
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I'm the original poster on the A/D forum. I see my old user name and password aren't working. Anyways....

I'm trying to connecto an A/D high speed counter/pulse output card to a GE servo drive. The drive manual explains to connect to the auxiliary encoder input, but is very vauge on how to do so. GE tech support is non-existent.

I've got the drive configured for CW/CCW pulse commands, but the drive has so many relevant inputs I can't figure out which one's to use. I've hooked the CW output of the card to the A+ encoder input, the CCW to the B+ of the encoder input, and the common on the card to the encoder 0V, and I get movement with pulses, but it is very erratic and unrepeatable. Something is not right, and I can't figure out what. I've tried several different other wiring configurations. There is one drive input called a 'tie' for singled-ended sources, but I don't know exactly how to incorporate it. The diagrams with the pulse output card only show how to hook the card up to a stepper amp, with a "opto-power" input, and a seperate 5vdc power supply. The GE drive supplies 5vdc for encoder operation, but I don't know how to tie that in with the drawing from A/D. Argghh!
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Old March 8th, 2004, 08:59 AM   #9
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Some of the relevant inputs and outputs I have on the drive are:

1-Positive for the A channel of the aux. encoder input
2-Positive for the B channel of the aux. encoder input
3-Tie to bias the aux. encoder inputs when used in single-ended mode
4-Signal common for 5v encoder power supply
5-Negative for the A channel of the aux. encoder input
6-Negative for the B channel of the aux. encoder input
7-5vdc for aux. encoder power

Right now I'm using 1,2, and 4, and getting some movement, but not proportional to the pulses I'm putting in, and not even repeatable.
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Old March 8th, 2004, 09:27 AM   #10
Steve Bailey
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What is the model number of the servo drive and the publication number of the manual for it? I'm not an expert on the AD module, but I know a little about some of the GE Fanuc servos.
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Old March 8th, 2004, 09:36 AM   #11
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Servo Drive Model: SSD104

Publication: GFK1866A


Thanks
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Old March 8th, 2004, 09:53 AM   #12
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The most liekly problem as I see it is a signal reference problem.
Are the counter module outputs set up to be sinking or sourcing? This will determine how the drive wiring needs to be set up to read the command pulse train.
I thnk you need to use terminal 3 on the drive to bias the receive circuit on the drive. Like Steve said, without the manual it's a little tough to tell you exactly what to do with it but I would certainly do something with terminal 3.
Some of the pulse style interfaces I have seem have a fixed pulse width output. The pulse width is fixed at a width equal to a 50% duty cycle at maximum output frequency. I don't know if the AD product does this, but if it does, that pulse width will be pretty short. You will want to use some high quality shielded cable with as short of run as you can to minimize the rise time in the signal. If the AD product maintains a 50% duty cycle regardless of frequency this isn't an issue.

I hope this helps.
Keith
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Old March 8th, 2004, 10:06 AM   #13
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I posted the last post before I looked at the manual. I assumed when you listed the signals you were using you listed them with their terminal/pin numbers. So that whole terminal 3 thing in my first post won't make much sense.
Anyway, on page 3-35 of the drive manual it says you want to tie the Tie terminal to INA- and INB- to bias the aux encoder inputs to accept single ended inputs. I think you want to use terminal 19 (+5 source for encoder) at the supply for your CW/CCW outputs on the AD product. Configure the encoder card jumpers for sourcing outputs and connect the +5 encoder supply to YC on the encoder card.
I suspect this will help you some.

Keith
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Old March 8th, 2004, 10:07 AM   #14
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I tried hooking 5 and 6, the negative encoder A and B inputs to 3, with no luck.
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Old March 8th, 2004, 10:12 AM   #15
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Excellent. I'll try it.

Thanks ahead. I'll let you know if it works.
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