RE: [CAD_CAM_EDM_DRO] 5V+ Supply for Gecko?

Abby:

The parallel port does not have 5V available on it. You CAN get +5V from
other places on the PC, such as the USB ports, the Game port(external), or
one of the drive power supply cables(internal).
The disadvantage of this is that you are running more risk of shorting out
your PC power supply when you take the 5V from the PC.

You can use the controller(old PC case with PC supply) to supply +5V,
+12V(and the other voltages, if you need them)), but in this case you will
have to make sure that the GND of the controller supply is tied to the GND
of the PC supply.

In either case, you will need to get +5V to the Geckos(from either the
controller or the PC), Step and direction to the Geckos(from the PC, either
direct or from your breakout board).

I don't have any experience with the Gecko Servo motor drives, but I looked
at the G320 docs, and it appears that the GND terminal is for the MOTOR
SUPPLY ONLY. You should NOT connect the PC or Controller supply ground to
the Gecko.

Also from the Gecko manual:

"The encoder must be a digital quadrature TTL output type that operates on a
single +5VDC power supply. The power
supply current rating must be less than 50 mA. It should be at least a 200
line encoder. If the encoder supply current is
more than 50 mA, use an external +5VDC supply. IMPORTANT: Connect a 470 ohm
resistor from TERM. 6 to TERM.
7 if an external power supply is used for the encoder."

If your encoder draws more than 50mA, you will need to use an external +5VDC
supply for the encoder. This supply should NOT be the one that is in your
PC, or in your controller. It is not specified, but it looks to me as if you
would connect the GND of the external +5VDC encoder supply to Pin 6 on the
Gecko, and to the GND of the encoder, and connect the +5VDC from the
external encoder supply to the +5V line of the encoder only, and make no
connection between this +5VDC and the Gecko.

Andy Wander
Verrex Corporation


-----Original Message-----
From: Abby Katt [mailto:cnc@...]
Sent: Wednesday, September 22, 2004 6:14 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] 5V+ Supply for Gecko?

Last Gecko message for a while, I promise! :)

I've scoured the Gecko docs and circuits online, but I still have a
question about Geckos and grounding/voltage. I've cleaned out an old
computer case to use as my servo driver box, and this gives me a nice
12v/5v power supply I can use for logic and driving 12V devices
(relays/cooling pumps etc) anyway, now I'm wondering if it wouldn't
have just made more sense to run a 5v power cable from the computer
to this box?

The Gecko manual says it wants 5V+ from the controller, it shows this
running through the opto-isolators and back to the STEP/DIR pins. I
was wondering, is it possible to just get this from a certain
parallel port pin? Or do I definately need a wire running from the
controller PC to gecko? Also, what's the deal with the encoder power?
Does it get this from the controller too (ie, will I need to connect
the controller ground to the ground pin on the gecko?) or does the
gecko use a voltage regulator internally to produce 5V from the 18-
80V power supply input?

I guess what I'm saying is, can I get away with using the 5V power
supply in my servo-box, and getting 5V from the parallel port,
without needing to run an extra wire from the PC?

Thanks!
~Abby