Yaskawa usarem motors, Amc be25a20 making it work?

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22 Dec 2018 04:33 #122743 by JR1050
This is the chart from the Amc hardware manual for the drives. I have found that pattern 17 and 34 work, although the motor runs smoother in one direction then the other. Yaskawa considers standard motor direction to be ccw while facing the driving end of the motor. It has also occurred to me that I'm asking to much from a rspi.


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05 Jan 2019 00:08 #123517 by JR1050
To use bldc , the encoder index enable has to be connected to the bldc index enable, however, the encoder index enable also has to be connected to the joint index enable. The issue:

With the encoder index enable solely connected to the bldc index enable
the motor motor homes immediately , meaning communtation is immediate. If I connect both of the mentioned pins to encoder index enable, the motor jumps all over while joint enable seems to cancel bldc
Index enable. one is setting the pin, the other is looking for it to be set.
I admit this is confusing . What is the best way for both bldc and joint index enable to share the encoder index enable with out conflicting?

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06 Jan 2019 16:22 #123613 by andypugh

To use bldc , the encoder index enable has to be connected to the bldc index enable, however, the encoder index enable also has to be connected to the joint index enable. The issue:

With the encoder index enable solely connected to the bldc index enable
the motor motor homes immediately , meaning communtation is immediate. If I connect both of the mentioned pins to encoder index enable, the motor jumps all over while joint enable seems to cancel bldc
Index enable. one is setting the pin, the other is looking for it to be set.
I admit this is confusing . What is the best way for both bldc and joint index enable to share the encoder index enable with out conflicting?


Do you definitely need the joint index enable? Have you configured HOME_USE INDEX?

You should make sure that the bldc is connnected to "rawcounts" from the encoder, or index-reset will cause all sorts of problems.

What pin drives the bldc "home" behaviour?

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01 May 2019 01:05 #132399 by JR1050
I've been away from this project for a while, life's distractions...

I found these drives to be readily available, AMC SX25A20A, they are a sinusoidal drive, would they work with the bldc component ? What Mesa hardware would be best suited. I attached the manual. Thanks.

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01 May 2019 03:02 - 01 May 2019 03:03 #132405 by Todd Zuercher
Replied by Todd Zuercher on topic Yaskawa usarem motors, Amc be25a20 making it work?
I think you could use a 7i77 (plus a suitable FPGA card like a 5i25) to control up to 3 of those drives (amps might be a better description), or add a 7i83 to that for a possible total of 6.
Last edit: 01 May 2019 03:03 by Todd Zuercher.
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01 May 2019 22:18 #132463 by JR1050
Andy, PCW,

How would one set this up? As far as i can tell, most,if not all, Mesa daughter cards are analog or step and direction. Your thoughts?

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01 May 2019 23:41 #132469 by PCW
This _is_ analog so as Todd Zuercher said a 7I77 should work
(with 2 analog axis per channel)

PCI/PCIE is probably better since its easier to get a 2-4 KHz or so update rate so the analog sine waves are not to steppy at full speed

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02 May 2019 02:42 - 02 May 2019 02:56 #132478 by JR1050
Ok, when I think analog drive I think single +/- 10v signal. It seems this drive was brought up by Todd before in this thread.

forum.linuxcnc.org/27-driver-boards/2121...ions?limit=6&start=0

"The drive requires two sinusoidal command signals with a 120-degree phase shift (external commutation).The phase angle must
correspond to the position of the motor rotor, while the signal amplitude controls the motor torque." 'Probably not your typical analog drive.

Andy brought up the difficulty of synchronizing two analog signals 120 deg apart. Was this ever figured out ? It was suggested the BLDC component could command this type of signal.

"How do you propose generating the 2 analogue voltages? They need to be synchronised to the rotor movement. I think that can be done in HAL with the bldc component and digital to analogue conversion (possibly PWM)
Do the motors have Hall sensors as well as the encoder?". From the above thread ^^^

Ill contact AMC and see if other information is available,these seem similar to the Mesa brushless amp, until then , any suggestions or hal examples?
Last edit: 02 May 2019 02:56 by JR1050.

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02 May 2019 03:17 - 02 May 2019 03:28 #132480 by PCW
The BLDC component is designed specifically to do this kind of control, you just use
two 120 degree separated phase outputs instead of all three that the component provides.
Only two phases are needed since the SX25A20A drive synthesizes the missing phase
( it's just the difference between the two supplied analog phase signals )

The BLDC component provides a variety of ways to establish rotor synchronization
including Hall signals, encoder index, magnetic align2ment, and absolute encpders
Last edit: 02 May 2019 03:28 by PCW. Reason: format a little better
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02 May 2019 03:32 #132481 by JR1050
Thank you PCW, now what hardware and how exactly would the two phase outputs be directed thru a 7i77 or 7133??

I can see a single drive signal from the output of either board, I can see physically wiring aout0 for ref A and aout1 for ref B, using two sets of drive signal per axis, but connecting the analog outs to the BLDC is gonna require some HAL voodoo in here some where along the line .

Standard analog is easy, step and direction is easy, this is bit more complicated..

Maybe a short hal example?

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