Re: [Emc-users] MESA 7i43

[Andrew <par...@gm...>]

2011/7/3 Ted Hyde <las...@gm...>:
> Andrew -
> You noted that you are using step/dir into servo drives - does it follow
> that your servo drives require those SPI interfaced encoders? In the
> servo drives I've encountered, if it has a step/dir mode, the drive is
> an intelligent one and handles the entire PID and feedback loop itself,
> meaning the encoder (or at least halls+) is fed directly to the servo drive.
>

I still have to check it. If SPI encoders are a part of the drivers,
then I just need all new encoders and 7i48. Then the only
condideration is mechanical - where to place the encoders. There's a
pulley belt transmission from motor to nut. If I install encoders to
the nut, I'm afraid to get unstable system because the belt is
compliant and the nut inertia is relatively large. So the simpliest
way to put it near existing encoder... which is kind of strange,
having 2 encoders side by side.

2011/7/3 andy pugh <bod...@gm...>:
> On 3 July 2011 13:52, Ted Hyde <las...@gm...> wrote:
>> Andrew -
>> You noted that you are using step/dir into servo drives - does it follow
>> that your servo drives require those SPI interfaced encoders?
>
> He  mentioned DMM-tech, which use an absolute position encoder (I
> think it is used for phase-control too, instead of Hall sensors).
> I think DMM are missing a trick by not outputting emulated quadrature
> pulses from the drive.

I'm afraid so. And there seems no encoder outputs from the driver.