EMC and 7i43

PCW
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11 Jul 2011 01:27 - 11 Jul 2011 01:30 #11374 by PCW

Replied by PCW on topic Re:EMC and 7i43

Do you mean your servo analog +-10 inputs are connected to the 7I33TAs analog output?
The 7I33 outputs +-10V analog suitable only for a +-10V servo input

Last edit: 11 Jul 2011 01:30 by PCW.

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efinkg
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11 Jul 2011 01:36 #11376 by efinkg

Replied by efinkg on topic Re:EMC and 7i43

I have them connected to the Analog Current Sense and Common pins on the servo amps. The manual lists +10v as being the top end RPM signal for a digital control spindle, which would make the other amps likely to be the same, though I don't have documentation directly stating that. What I am surprised by is that there appears to be no signal output by the 7i33 pins.

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PCW
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11 Jul 2011 01:44 #11377 by PCW

Replied by PCW on topic Re:EMC and 7i43

That sounds completely wrong...
If you connect the 7I33 to a current sense input the 7I33 outputs may be shorted out
Try the outputs first with no load...

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efinkg
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11 Jul 2011 01:50 #11378 by efinkg

Replied by efinkg on topic Re:EMC and 7i43

I see a jump from .3mV to .4mV. When connected to the servo amp I have a resistance of .287kOhm

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PCW
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11 Jul 2011 01:54 #11379 by PCW

Replied by PCW on topic Re:EMC and 7i43

A current sense input is just wrong and you may damage the 7I33 by such a connection which
is why I said to test first with no load (nothing connected to the 7I33s except the encoders)
do you have manuals for the drive? there should be something like analog command input or analog velocity input

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efinkg
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11 Jul 2011 02:02 #11380 by efinkg

Replied by efinkg on topic Re:EMC and 7i43

I don't believe I have the manuals for the drives, I can continue searching if essential. The hookups I have listed are Common, +/- Limit Switch, Tachometer/Return DAC/Return and Analog Current Sense.

Thanks so much.

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PCW
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11 Jul 2011 02:14 #11381 by PCW

Replied by PCW on topic Re:EMC and 7i43

My bet would be on DAC/return (DAC to 7I33 AOUT. return to 7I33 GND)
Bu I would first verify that
1. The 7I33s analog outputs work (with no load connected)
2. the DAC inputs are high impedance (>5K)

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cncbasher
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11 Jul 2011 07:41 #11383 by cncbasher

Replied by cncbasher on topic Re:EMC and 7i43

post information on the drives you have , and or show picture of the connection and any plate information , someone may be able to identify them
prove the drives work before connecting to the 7I33TA

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andypugh
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11 Jul 2011 10:09 #11386 by andypugh

Replied by andypugh on topic Re:EMC and 7i43

PCW wrote:

If you connect the 7I33 to a current sense input the 7I33 outputs may be shorted out

if it is a 4-20mA connection, you can probably create a working system using a 500R resistor and by setting the deadband of the PID so that it always gives at least 20% output, and the PWM such that the voltage is unipolar (assuming a separate direction pin)

This assumes that the 7i33 analogue output can handle a 20mA current, of course.

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PCW
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11 Jul 2011 13:50 #11400 by PCW

Replied by PCW on topic Re:EMC and 7i43

The 7I33 will not drive 20 mA loads at least not on all outputs simultaneously. Its designed to drive
analog +-10V inputs

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