8i20

PCW
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01 Mar 2022 23:40 - 02 Mar 2022 00:14 #236145 by PCW

Replied by PCW on topic 8i20

Does the init cycle run without fault?

What I am getting at is that you may get faults due to instability,
either in LinuxCNCs PID = LinuxCNC PID tuning issues or in the 8I20.
If you cannot set a static current in the 8i20 without fault, its likely the
8I20s current loop PI gains are too high for your motor.

Last edit: 02 Mar 2022 00:14 by PCW.

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andypugh
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02 Mar 2022 00:14 #236146 by andypugh

Replied by andypugh on topic 8i20

dkraft wrote:
setp [HMOT](CARD0).0.8i20.0.0.current-maxlim 0.020
setp [HMOT](CARD0).0.8i20.0.0.current-minlim -0.020

Is this just for testing? I have forgotten how the calculations work, but this seems odd.

I run both my machines with 8i20, but as they have resolvers the configs won't transfer straight across.

net x-meas-angle bldc.0.rotor-angle => hm2_5i23.0.8i20.0.2.angle
setp hm2_5i23.0.8i20.0.2.current-maxlim 7.5
setp hm2_5i23.0.8i20.0.2.current-minlim -7.5
net x-cmd  joint.0.motor-pos-cmd => pid.0.command
net x-vel-cmd joint.0.vel-cmd => pid.0.command-deriv 
net x-fb hm2_5i23.0.resolver.01.position pid.0.feedback joint.0.motor-pos-fb
net x-vel-fb hm2_5i23.0.resolver.01.velocity pid.0.feedback-deriv
setp hm2_5i23.0.resolver.01.velocity-scale -1
net x-pid pid.0.output => hm2_5i23.0.8i20.0.2.current

#12 motor 49 pulley 5 leadscrew pitch
setp hm2_5i23.0.resolver.01.scale -1.2244898

net amp-enable-and-DC-good pid.0.enable
setp pid.0.Pgain [JOINT_0]PGAIN
setp pid.0.Igain [JOINT_0]IGAIN
setp pid.0.Dgain [JOINT_0]DGAIN
setp pid.0.bias [JOINT_0]BIAS
setp pid.0.FF0 [JOINT_0]FF0
setp pid.0.FF1 [JOINT_0]FF1
setp pid.0.FF2 [JOINT_0]FF2
setp pid.0.deadband [JOINT_0]DEADBAND
setp pid.0.maxoutput [JOINT_0]MAXOUTPUT

setp bldc.0.scale -16777216
setp bldc.0.poles 6
setp bldc.0.lead-angle 0
setp bldc.0.encoder-offset -950000

Try with the max and min current matching the nvmaxcurrent (7.5A = 0x2EE, which you seem to have)

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dkraft
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02 Mar 2022 13:16 #236166 by dkraft

Replied by dkraft on topic 8i20

Its the init that trips it. struggling with a way to diagnose it.

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andypugh
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02 Mar 2022 14:01 #236172 by andypugh

Replied by andypugh on topic 8i20

Does it always trigger? Or is it OK the second time? I am wondering about transient effects as the rotor snaps in to phase.

I guess you have tried both higher and lower initvalue values?

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dkraft
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02 Mar 2022 14:01 #236173 by dkraft

Replied by dkraft on topic 8i20

How do you drive the input enable and read the fault out physical pins on the 8i20? Do you setup pins from the driver board?

Currently testing, I'm driving input enable from 5v off the serial connector.. not sure if that is trouble.

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dkraft
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02 Mar 2022 17:57 - 02 Mar 2022 23:10 #236201 by dkraft

Replied by dkraft on topic 8i20

Figured out the tripping error. Too low impedance on the motor detects as a short apparently.
250Kv motors will never work no matter how low you try to drive it

Thanks!

Last edit: 02 Mar 2022 23:10 by dkraft.

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andypugh
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02 Mar 2022 18:12 #236202 by andypugh

Replied by andypugh on topic 8i20

Are these RC aircraft motors?

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PCW
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02 Mar 2022 18:47 #236205 by PCW

Replied by PCW on topic 8i20

Yes I forgot to ask this, what type of motor and perhaps more important, what is the motor inductance?

The 8I20 is intended for medium/high inductance motors (standard AC 230V servo motors)

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dkraft
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02 Mar 2022 23:09 #236225 by dkraft

Replied by dkraft on topic 8i20

yes. I thought I'd be clever and debug with a low inductance motor, didn't work. got it working with a washing machine motor though..

Moving on to the yaskawa servo motors now.

Your help with the commutation signals was crucial. Thank You.

Last piece was bldc.init

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dkraft
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15 Mar 2022 12:34 #237321 by dkraft

Replied by dkraft on topic 8i20

How can I get my encoder offset ?
I'm thinking it's aligned with the "U+, VW-" method, then average the 6 positions found modulus encoder scale / poles...

(I hacked a CMT102 on a servo with 6 poles)

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