Re: [CAD_CAM_EDM_DRO] AC Servo's

Wayne Weedon wrote:

>Hi
>
>Just picked up my latest project. a 1992 vintage Leadwell machining
>centre.
>
>This machine has a Mitusbishi Meldas 310M control which is faulty, and
>likely to be a liability to keep.
>
>The machine has AC Servo Motors (HA330-TS) each fitted with a 5000 ppr
>encoder.
>
>The drives are MR-S series which are Digital drives, but use
>Mitsubishi's own proprietary protocol. Its seems very unlikey that
>they could be used with any of the current PC based controls.
>
>

Well, look into it before giving up. There may be a way to set the servo
drives up for either analog velocity command or step/direction. If it will
take analog velocity, then you can use a Servo-to-Go card, or my PPMC
board set, to drive it.

>So my question is to the servo experts here, what are my options?.
>
>Of course there's a lot of drives out there, both analogue and digital
>(Step/dir) All seem to be tailored to a particular series of motors.
>
>I'd probably prefer a digital setup, but fear I may have to change both
>motors and drives?
>
>

Yes, keeping the drives is the best option, if possible. Some drives can
accomodate a variety of motors, others are strictly proprietary. You need
to check if the encoder has standard commutation outputs, or if the motor
provides these (the typical Hall A,B C outputs.) Yaskawa servo pack
drives use a proprietary scheme where the "Z" channel of the encoder has
a phase relationship to the A and B encoder tracks that gives the drive
the index position as well as the commutation info. So, both the drives
and the motors are totally proprietary, and can't be used with anything
else. A number of other makers have similar schemes.

>Other than that the machine was a bargain;-) (750 GBP/$1300) I just
>wanted a small VMC with ATC.
>
>

Given a little more info, we might be able to track down some info on
these motors and drives. I did find some Mitsubishi info on
mel servo amps of the MR-J2S series. The MR-J2S-A takes analog
velocity command inputs. The MR-J2S-B uses SSCNET. The MR-J2S-CL
is basically a one-axis NC control, kind of like a super-indexer.
This document is at
http://www.mitsubishi-automation.de/service/techcat/pdf_download/113788.pdf
Acrobat 5 says the document is damaged, but Acrobat 7 reads it fine.
(Usually, Acrobat will say the document contains functions it can't display
and then renders it the best it can.) This document lists compatibility
with
HC-xxxx motors, so your drive may be an earlier model of this series.

Jon