Inverse current

13 years 11 months ago #13744517 by tiano
Inverse current was created by tiano
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN lang=EN-GB style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Hello,</SPAN></FONT>
<P class=MsoNormal style="MARGIN: 0px"><FONT face=Arial color=navy size=2><SPAN lang=EN-GB style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I would like to make a question about the controller. I connect power supply and motor wires like appears on controller’s datasheet, but when I set proportional gain (you can set proportional, integral or differential gains) to zero, with the others parameters set to zero too, the controller shouldn’t give power to the motor (according to the expression: Applied Power = (Command Value – Actual Position) * Proportional Gain), but this doesn’t occurs and a current (of the order of 1 A) drives through the motor when a load is applied to the motor. Why does it happen? How can I eliminate this current?</SPAN></FONT>
<P class=MsoNormal style="MARGIN: 0px"><FONT face=Arial color=navy size=2><SPAN lang=EN-GB style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT>
<P class=MsoNormal style="MARGIN: 0px"><FONT face=Arial color=navy size=2><SPAN lang=EN-GB style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I have been tested the motor and it generate a voltage (about 10 V) when I apply a load on it and the controller is disconnected.Can this be the cause of my problem?</SPAN></FONT>
<P class=MsoNormal style="MARGIN: 0px"><FONT face=Arial color=navy size=2><SPAN lang=EN-GB style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT>
<P class=MsoNormal style="MARGIN: 0px"><FONT face=Arial color=navy size=2><SPAN lang=EN-GB style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Thanks</SPAN></FONT>
<P class=MsoNormal style="MARGIN: 0px"><FONT face=Arial color=navy size=2><SPAN lang=EN-GB style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT>

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13 years 11 months ago #13751574 by cosma
Replied by cosma on topic Re:Inverse current
<P style="MARGIN: 0px">It would help to know in which mode you are using the controller. I assume it is in position mode.
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<P style="MARGIN: 0px">It is correct that with gains of 0 everywhere there should be no output.
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<P style="MARGIN: 0px">The best way to test that the PID works as expected is to operate the controller using the Roborun utility, with no motors connected at first.
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<P style="MARGIN: 0px">If you are using a potentiometer for feedback, you will need to make a custom cable so that you can connect the feedback info and the RS232 at the same time.
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<P style="MARGIN: 0px">Then, in the Run tab of Roborun, you will be able to see the output power level based on the command value and measured feedback.
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<P style="MARGIN: 0px">If the D and I are at 0 and only P has a &gt;0 value, you will be able to observe that the applied output power is the error (command - feedback) * gain.
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<P style="MARGIN: 0px">Output should always be at 0 if all gains are at 0.
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<P style="MARGIN: 0px">After you are satisfied that the PID operates as the mathematics predict, then you should connect the motor.
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<P style="MARGIN: 0px">There should not be any problem having the motor connected while spinning. It may or may not be the reason you see the 1A that you report.

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