Andy We did a test by putting a pot onto the input pins of the drive and it was more than happy. No oscillations at all and we could move the motor very smoothly with the pot. That means the drive is happy with the encoder as a simulated tacho. I have not measured the 5v from the 5i25 or the 24v filed voltage with a scope to see if there are noise on them. I have to measure the analog output as well to see if I can get where the oscillations are coming from.
Question - is there any way that the feedback can be delayed so long that the PID will not function correctly? I set the PID from very slow to very aggressive but with very little effect. If the oscillations are due to induced noise on the output signal, then I will not be able to tune it out with the PID. On 2014-03-05 12:36, andy pugh wrote: > On 5 March 2014 05:11, Marius Liebenberg <[email protected]> wrote: > >> 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. > It sounds like the simulated-tacho isn't doing a very good job. > > One (off-the-wall) option might be to use a spare 7i77 analogue output > as a simulated tacho based on the Mesa-measured encoder velocity. > This ought to be worse than the system you have now, but there is the > option of tweaking deadbands and linearisation curves etc in HAL, so > at least you are not working blind. > -- 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
