Dave I disconnected the 7i77 from the drive completely. It should stand still with no input but it oscillates and the adjustments made no impact at all.
On 2014-03-04 23:43, Dave Cole wrote: > Try disconnecting the 7i77 entirely from the drive and hook a constant > voltage source to the drives input - I oftentimes use a 1.5 volt battery > ( an isolated voltage source ). > > Disconnect the load from the motor so the shaft can turn freely. > > There should be some instructions for tuning the drive like this as a > velocity mode drive. > > Run the motor in one direction, then reverse the battery to run it in > the other direction. > > See if you can tweak the drive so that it runs smoothly, and at a > constant speed. > > If the drive is not stable using the battery, it will never be stable > hooked up to the 7i77. > > Dave > > On 3/4/2014 3:35 PM, Marius Liebenberg wrote: >> 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 <[email protected]> >>>> Reply-To: "Enhanced Machine Controller (EMC)" >>>> <[email protected]> >>>> To: "Enhanced Machine Controller (EMC)" <[email protected]> >>>> 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 >>> (")_(") signature to help him gain world domination. >>> >>> >>> ------------------------------------------------------------------------------ >>> 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. >>> http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk >>> _______________________________________________ >>> Emc-users mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/emc-users >>> > ------------------------------------------------------------------------------ > 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. > http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- 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. http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
