Wiring and configuration SERVO DRIVES

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TomKerekes
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Re: Wiring and configuration SERVO DRIVES

Post by TomKerekes » Mon Nov 23, 2020 9:24 pm

The DAC maximaze at 10v and the drive won't respond.
10V to the Amplifier should cause the motor to drive full speed. So the next step would be to figure out why the motor isn't driving. Are you connecting the DAC to IN_B? Did you connect a Kanalog GND to SGB? If so, what voltage do you measure across IN-B to SGB?
Regards,

Tom Kerekes
Dynomotion, Inc.

GabrielR922
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Re: Wiring and configuration SERVO DRIVES

Post by GabrielR922 » Mon Nov 23, 2020 9:58 pm

Tom,

The drive just don't drive if drive encoder 0v is connected to kanalog ground, so +/-10 wiring should be correct, as it works without this ground.

The SGB is wired to kanalog JP11 GND and the INB is wired to the 10v.

The encoder goes to the drive and then comes to kanalog. so it's 0v is wired to the drive.

If wired the 0v from the drive to the kanalog it won't work.

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TomKerekes
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Re: Wiring and configuration SERVO DRIVES

Post by TomKerekes » Mon Nov 23, 2020 10:15 pm

Hi Gabriel,
The drive just don't drive if drive encoder 0v is connected to kanalog ground
Yes we need to figure out why. The Kanalog differential inputs require a ground reference.

so +/-10 wiring should be correct, as it works without this ground.
not necessarily.

The SGB is wired to kanalog JP11 GND and the INB is wired to the 10v.
Do you mean the DAC? Which is at a 10V level? Did you measure across INB to SGB right at the Drive with a voltmeter? What Voltage does it read? It might be easier to command any DAC voltages from the Console Screen with DAC0=2000, but the KFLOP axis must be disabled.

Are there any other connections to the Drive?
Regards,

Tom Kerekes
Dynomotion, Inc.

GabrielR922
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Re: Wiring and configuration SERVO DRIVES

Post by GabrielR922 » Tue Nov 24, 2020 11:04 am

Hi Tom.
Do you mean the DAC? Which is at a 10V level? Did you measure across INB to SGB right at the Drive with a voltmeter? What Voltage does it read? It might be easier to command any DAC voltages from the Console Screen with DAC0=2000, but the KFLOP axis must be disabled.
The drive SGB is wired to drive JP11 GND
The drive INB (auxiliar input, 2-10v) is wired to JP11 DAC

Doesn't the differential encoder compare A+ and A- voltages? is it need a other ground for it to work ?
Looking to the drive schematic, it seems that the 0v is used to open collector use.
Capture.PNG
Look this wiring below, it shows it also.
servo1.PNG

Thanks Tom

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TomKerekes
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Re: Wiring and configuration SERVO DRIVES

Post by TomKerekes » Tue Nov 24, 2020 4:07 pm

Hi Gabriel,
The drive SGB is wired to drive JP11 GND
The drive INB (auxiliar input, 2-10v) is wired to JP11 DAC
This seems correct.

Doesn't the differential encoder compare A+ and A- voltages?
Yes

is it need a other ground for it to work ?
Yes it does to make sure the common mode voltage is within limits. Otherwise it may not work correctly or damage the inputs.

Looking to the drive schematic, it seems that the 0v is used to open collector use.
No, the schematic shows the differential drivers and the open collectors use the same ground reference.


The main thing is connecting the ground should not cause the Drive to stop working. This indicates a major issue with your wiring or grounding. Please answer my previous questions and perform the tests requested.
Regards,

Tom Kerekes
Dynomotion, Inc.

GabrielR922
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Re: Wiring and configuration SERVO DRIVES

Post by GabrielR922 » Tue Nov 24, 2020 4:51 pm

Hi Tom.

The wiring in the drive can't be wrong. the Machine was original and i just cutted the other end of the cable (CNC end) and plugged to kmotion. The cnc was operating before i started retrofit.

my wiring is exact like this:
https://www.dynomotion.com/wiki/index.p ... c3Axis.pdf

Did the test you told me.
DAC output is 0.9v (no cable connected) encoder 0v cable connect, gives the same 0.9v.

With DAC connect to the drive, if i connect the encoder 0v the DAC goes to 0.

Thanks

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TomKerekes
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Re: Wiring and configuration SERVO DRIVES

Post by TomKerekes » Tue Nov 24, 2020 6:08 pm

Hi Gabriel,
The wiring in the drive can't be wrong. the Machine was original and i just cutted the other end of the cable (CNC end) and plugged to kmotion. The cnc was operating before i started retrofit.
Well something is obviously wrong, correct? It is hard to find out what is wrong if you assume everything is correct.

Why are the signal names different from what you posted before?

Where are you making the ground connection?

Did the test you told me.
DAC output is 0.9v (no cable connected) encoder 0v cable connect, gives the same 0.9v.

With DAC connect to the drive, if i connect the encoder 0v the DAC goes to 0.
I don't understand exactly what you are doing.

What value was the DAC commanded to?

Where are you measuring and relative to what?

Why was it 0.9V?

If connecting the cable forces the DAC output to 0V that would indicate a short in the cable. Did you know how to check for shorts?

This should be fairly easy to figure out, but if you don't want to figure it out let me know.
Regards,

Tom Kerekes
Dynomotion, Inc.

GabrielR922
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Re: Wiring and configuration SERVO DRIVES

Post by GabrielR922 » Tue Nov 24, 2020 6:43 pm

Hi Tom.
Surely I wan't to figure it out, but i don't think a configuration that worked for 25 years is wrong. Maybe it's not compatible with Kanalog or the NUM CNC did something inside the cnc with the 0V?

The drive have SGB and INB that are the inputs for speed reference.

This are connected do DAC(INB) and DAC GND(SGB).

The Encoder is connected to the drive with A+ A- B+ B- C+ B- / 0V and 5V
The drive is grounded

The encoder output from the drive is connected to A+ A- B+ B-.
The drive also has a 0V output from the encoder.

So, assuming nothing is connected,
The encoder output from the drive and the analog SGB don't short.

Then I connect INB and SGB to DAC and DAC GND.
Console output 100dac.
DAC Output is 0.9v

Ground (JP6 ground) the 0V from the drive encoder output.
The DAC output goes to 0.



Resuming:
The encoder is grounded in the drive and the drive output a 0V.
If the 0v is connected to the Kanalog GND, the DAC output zero out.

If kanalog is grounded (and encoder 0v not connected), the DAC works fine.

Maybe my explanation is more clear now.

Thanks Tom!

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TomKerekes
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Re: Wiring and configuration SERVO DRIVES

Post by TomKerekes » Tue Nov 24, 2020 7:22 pm

Hi Gabriel,
Maybe my explanation is more clear now.
Yes.
Ground (JP6 ground) the 0V from the drive encoder output.
The DAC output goes to 0.
That would indicate a short between INB and 0V as shown in red below. The red-dot path would be the cause of the DAC being forced to 0V.

With power off what is the measured resistance between the DAC wire and 0V?

Short.png
Regards,

Tom Kerekes
Dynomotion, Inc.

GabrielR922
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Re: Wiring and configuration SERVO DRIVES

Post by GabrielR922 » Tue Nov 24, 2020 9:19 pm

Hi Tom.

with no power.

The resistance is 4M 0V and GND
But its short with the dac + signal. maybe i need to invert DAC + and - ?

The + is red.

If i disconnect the connector from the drive, it dont short.
So the short is inside the drive.

Thanks

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