Step/Dir Servo Closed Loop with Encoder
- Type_Zero_Design
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11 Aug 2019 06:28 #141894
by Type_Zero_Design
Step/Dir Servo Closed Loop with Encoder was created by Type_Zero_Design
Hello Everyone,
Starting this thread here to prevent continuing to clutter Tommy's PID tuning thread. I have attached my current .Hal file.
So as the title says I am looking to figgure out how to close the loop in LCNC with my Step/Dir servos. I have been doing a ton of searching and reading the .Hal manual but still struggling to figgure out exactly what needs to be done to complete this in Hal.
Currently, I can jog the machine and have confirmed that I am getting accurate movment on all axis. I know that I need to connect my encoders to the correct areas, but i'm not 100% on what those are.
Im not sure what the encoder name is to even to connect to.
Also ive seen mention of setting up the stepgen in velocity mode but i dont see the line mentioned to do that in my .hal file
I appreciate the feedback.
Starting this thread here to prevent continuing to clutter Tommy's PID tuning thread. I have attached my current .Hal file.
So as the title says I am looking to figgure out how to close the loop in LCNC with my Step/Dir servos. I have been doing a ton of searching and reading the .Hal manual but still struggling to figgure out exactly what needs to be done to complete this in Hal.
Currently, I can jog the machine and have confirmed that I am getting accurate movment on all axis. I know that I need to connect my encoders to the correct areas, but i'm not 100% on what those are.
Im not sure what the encoder name is to even to connect to.
Also ive seen mention of setting up the stepgen in velocity mode but i dont see the line mentioned to do that in my .hal file
I appreciate the feedback.
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- Hakan
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11 Aug 2019 07:42 #141900
by Hakan
Replied by Hakan on topic Step/Dir Servo Closed Loop with Encoder
What hardware do you have to read the encoders? 7i85?
To close the loop there is really one line to change
toprovided the encoder is called that.
Then you need to adjust the PID parameters. This should hopefully get you going at least
My guess is that you have the velocity loop in the servo controller and adjust it using the controller software.
To close the loop there is really one line to change
net x-pos-fb <= hm2_7i76e.0.stepgen.00.position-fbnet x-pos-fb <= hm2_7i76e.0.encoder.00.positionThen you need to adjust the PID parameters. This should hopefully get you going at least
P = 1
I = 0.0
D = 0.0
FF0 = 0.0
FF1 = 1.0
FF2 = 0.0
BIAS = 0.0
DEADBAND = 0.0
MAX_OUTPUT = 0.0My guess is that you have the velocity loop in the servo controller and adjust it using the controller software.
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- andypugh
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13 Aug 2019 18:37 #142067
by andypugh
You are already set up in velocity mode:
In fact, as was pointed out in the post above, you only actually need to change part of one line.
You might also need to add a little bit of I-gain to make use of the feedback.
Replied by andypugh on topic Step/Dir Servo Closed Loop with Encoder
Also ive seen mention of setting up the stepgen in velocity mode but i dont see the line mentioned to do that in my .hal file
You are already set up in velocity mode:
setp hm2_7i76e.0.stepgen.00.control-type 1In fact, as was pointed out in the post above, you only actually need to change part of one line.
You might also need to add a little bit of I-gain to make use of the feedback.
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