Re: BDI and servos

Ray, is there a trade show where these things can be seen? (I'm in
Northern KY)

Jim

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Ray Henry <rehenry@u...>
wrote:

>
> >    From: Bob Simon <bsimon@q...>
> > Subject: BDI and servos
> >
> > Can the Brain Dead Install of EMC be used with analog servo

systems or

> > is it specifically set up for step and direction only?
>
> You can use the EMC (BDI includes a full EMC) to drive either

stepper or

> servo motors. The choice is made by a single variable in the ini

file

> that is read during startup. It is also easily possible to write
> multiple personalities for the EMC on a single machine and start

any

> using a single command or icon. (if you are a point-n-click kinda

person

> and set it up that way)
>
> In the case of full servo control by the PC, in contrast to step

and

> direction servo control like Gecko 3xx or 4xx amps, you'll need a

board

> or board set that will make the analog(ue) signals that will drive

the

> amps. With a servo driver software module like stgmod you have ini

file

> control of max and min voltage and zero or bias as some call it.

You

> will also have a full PID loop with the usual feed forward

computations.

>
> I saw a demo of a mill that ran with either the usual velocity

control

> from the EMC or current control using the same computations. The
> velocity control included amps that used tach signals for speed

feedback

> while the current loop ignored the tach signals and used position
> computation right out of the PC. I couldn't tell the difference

in

> control of the motors during accel/decel or during smooth motion

at most

> any speed. But having said this I have to say that the guy that

did the

> demo had some pretty sophisticated proprietary tuning routines and

knew

> how to use them.
>
> You will also need something to read the encoders for position.

There

> are a few companies that make combination boards for both these

sets of

> signals. The most common is the Servo-To-Go but more recently the

EMC

> developers have added Vigilant and are working on Studio

Ferraris. An

> interesting alternative to the PC cards is Jon Elson's (PICO)

parallel

> port motion control board sets.
>
> HTH
>
> Ray
>
> FYI - I have a tiny vested interest in PICO's servo boards. I

sell the

> BDI disks for about a 1% profit. I have a HUGE

interest/investment in

> the EMC.