GS M-Series Galvo information

[Andy Cleary]

Hello,

I need some information on the General Scanning M-Series Galvo, Model
M2, # 000-3008522. (see
http://www.gsilumonics.com/product_data_sheets_en/276.html)

1) Anyone have the M-Series pinout? It is a DB9 Male connector...

2) Do these galvos have any torsion mechanism in them? Someone told me
they have "Magnetic Torsion"? Or do they just use the capacitive
feedback mechanism for closed-loop control?

3) Based on #2, what should the shaft feel like in these? Should it
move freely, or should there be some resistance? I have one that almost
feels like a stepper motor (maybe it's bad?)

Finally, for anyone interested, I cracked one open to have a look-see
inside:

http://web.a-znet.com/~teslacoiler/pics/GS%20galvo/inards.JPG
Thanks in advance,

-Andy C.

[ost...@akrobiz.com]

Andy Cleary wrote:
> Hello,
>
> I need some information on the General Scanning M-Series Galvo, Model
> M2, # 000-3008522. (see
> http://www.gsilumonics.com/product_data_sheets_en/276.html)
>

Naw, the before tuning torsion is generated by a "electronic spring"
circuit in the minisax amp and after the amp is tuned the by the
feedback loop. Otherwise it should flow from stop to stop when you
handle it. its not really loose like a dc motor, but can freely swing
with no power on.

full details are on the GSI-Lumonics web site, look at the "minisax"
amplifier.

Steve Roberts

[LesioQ]

Stepping motor feel in galvo will usually indicate worn ball bearings.
Unless You're expecting top-quality response, it should work OK for
simple applications. Typical feel for this galvo is free movement. No
spring action. Same as optically-feedbacked Cambridges. Not sure about
pin-out, they come with various connectors incl. RJ-45, DB-15. Usually
both coils are paralleled inside, rest of signals typical for G120
(positon pos/neg, 12V supply, )
LesioQ

[Andy Cleary]

Steve, LesioQ,

Thanks for the responses. I think you probably hit the nail on the
head as far as the worn bearings go. That would make sense... I don't
have much experience with non-torsioned galvos.

As far as the pinout goes, I did some investigation and
cross-referencing with other galvos and the minisax controller. For
the record, this is what I discovered:

GSI M-Series Galvo pinout for DB-9 Male connector
--------------------------------------------------------------------------
Pin 1: Galvo Coil +
Pin 2: GND
Pin 3: GND
Pin 4: NC (not connected)
Pin 5: Feedback (AC signal riding on -24VDC)
Pin 6: Galvo Coil -
Pin 7: GND
Pin 8: Power +12 or 15
Pin 9: Feedback (AC signal riding on -24VDC)

Disclaimer: I don't know if this is totally right, but when power is
applied, the HV 3Mhz feedback oscillator comes on, and moving the shaft
results in some sort of feedback on pins 5/9. Power to the coil
connections results in movement of the shaft. Of course, any damage
that results from the use of this information is your own fault, and I
will not be held responsible :)

-Andy C.