Hi Peter
That is what I did but it seems that no matter how I turn the variable
resistors (multi turn pots) they oscillation remains as strong. There
are some instruction on tuning the drive when using a tacho but nothing
for the encode option. I even tried to remove the feedback to the drive
and go through LCNC for the PID loop. I still cant get rid of the
oscillating feedback
The customer has a set of drives that was supplied by Mesa and I
wondered how you would go about connecting the setup if I had to remove
the drives and replace them with the Mesa drives. I dont know if these
Minibravos are such great drives as I have never encountered them before.
On 2014-03-04 21:50, Peter C. Wallace wrote:
> On Tue, 4 Mar 2014, Marius Liebenberg wrote:
>
>> Date: Tue, 04 Mar 2014 21:38:42 +0200
>> From: Marius Liebenberg <mar...@mastercut.co.za>
>> Reply-To: "Enhanced Machine Controller (EMC)"
>> <emc-users@lists.sourceforge.net>
>> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net>
>> Subject: [Emc-users] Servo system oscillating feedback
>>
>> I installed a Mesa 5i25 with 7i77 to drive a Minibravo 60 Brushed DC
>> motor drive. It drives a Brushed DC motor (ESA 3M 8019) from Motor Power
>> Company. There is a encoder fitted to the motor. Also an ESA 3Mxx? There
>> is a 10:1 planetary gearbox fitted to the shaft.
>>
>> The Minibravo's are designed to work with a tacho and has a tunable PID
>> interface when using the tacho. These drives are fitted with an encoder
>> interface board that turns the pulses into an analog voltage that is
>> supposed to be representative of the rpm of the motor. When the encoder
>> option is used it seems that the PID is not in circuit.
>>
>> The problem is that I get a constant severe oscillation when the motor
>> is in rest as well as when it is driven. When I scope it with Halscope,
>> I see the constant ripple on the feedback count as well. If I remove the
>> analog input signal to the drive, I still get the oscillation.
>>
>> Has anyone have any experience with this kind of setup. Your assistance
>> will be appreciated :)
>>
>> --
>>
>> Regards /Groete
>>
>> Marius D. Liebenberg
>> +27 82 698 3251
>> +27 12 743 6064
>>
>
> I would expect that there is a PI velocity control loop in the drive that
> takes the simulated tachometer signal as the velocity feedback.
>
> If the driver/motor oscillates without any feedback from LinuxCNC you will
> need to lower the drives P/I gains until it is stable before proceeding.
>
>
>
>
>
> Peter Wallace
> Mesa Electronics
>
> (\__/)
> (='.'=) This is Bunny. Copy and paste bunny into your
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>
>
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--
Regards /Groete
Marius D. Liebenberg
+27 82 698 3251
+27 12 743 6064
------------------------------------------------------------------------------
Subversion Kills Productivity. Get off Subversion & Make the Move to Perforce.
With Perforce, you get hassle-free workflows. Merge that actually works.
Faster operations. Version large binaries. Built-in WAN optimization and the
freedom to use Git, Perforce or both. Make the move to Perforce.
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