Re: help for a newbie

--- In CAD_CAM_EDM_DRO@y..., "ksprayberry428" <kellys@m...> wrote:

> I checked the voltage from pins 18-25 to terminal 10 and I have

5.37

> volts.I'm sorry, but I don't exactly follow what you mean by. - The
> return for the 5 volts needs to be at the same ground as the PC.
> Thanks
> Kelly

Okay, here's some things to try:

DO THESE TESTS WITH THE GECKO's DISCONNECTED FROM THE COMPUTER.

Build yourself a poor man's logic probe. Use an LED with a 470 ohm
resistor (yellow-violet-brn) soldered to either leg of the LED. Test
the "probe" by connecting it with the Anode to the +5 supply source
and the Cathode to Ground (small insulated clip leads can help
here) . If it lights you have connected everything right. Failure to
light might indicate the LED is backwards. If you get real
industrious you can use two seperate leds hooked up with resistors.
Then you can monitor both step and direction signals at the same time.

Now, leave the Anode(s) connected to to +5 and the cathode(s) to one
of the signal lines (step and/or direction) on the appropriate pin(s)
of the parallel port. You might want to use a breakout card (if you
have one) or an old DB25 connector to make the hookup easier. Fire
up your control program on the computer and do some slow jogs on the
axis where you have the LED. With the DIRECTION pin you should see
the LED go off and on in a steady state as you change the direction
of the jog. The glow should be bright and steady when it comes on.
If no change in the lamp, make sure your software is setup for the
correct PC port (normally hex378 - LPT1)and you have correctly
defined the pins for that output signal. If the LED does not glow as
brightly as when it was connected directly across the +5 then suspect
that your parallel port pin definitions between step and direction
have been switched (normally causes the motor to rotate erratically)
or that your parallel port is not able to "sink" enough current to
properly drive the Optoisolators in the Gecko's.

The STEP pins will glow less bright because they are being pulsed.
If they do not change state when you jog then you are not getting
signal to that pin.

To test the input of the Gecko's: Apply motor power with a motor
connected. Connect the seperate + 5 and ground (from the +5 source)
to the correct INPUT pins. Disconnect the signal (step and
direction). With a clip lead on the direction pin of the Gecko
momentarily ground the pin to the ground from the +5 source THIS IS
NOT THE GROUND FOR THE MOTOR POWER SUPPLY. The motor should "twitch"
each time you ground the step pin. The direction may not be
predictable but it proves the GECKO is probably fine and will run if
given the correct level of signals.

All of this becomes easier to do if you have test equipment but
simple voltmeters can be hard to read correctly. A scope is handy
but most guys don't have that type of equipment laying around.

Since the optoisolator is just an LED and a light sensitive
transistor the little rig I describe allows you to "see" the signal
that normally happens inside the opto.

Let us know if you still are having problems.