Re: help for a newbie

Hi Kelly,

a couple things to check.

obviously the power voltage to the Gecko,
the current set resistor for that Gecko/stepper combination
and the signal speed.

set the rate of steps to about 1,000 (one hz) I found on my initial
testing I was too ambitious and over sped the stepper. Once I
reduced it into it's operating window, I was able to increase the
envelope to what I expected. At 1 hz, you should have a pretty
unstoppable motor. I have a double stack NEMA23 (50in/oz ? ) and I
have a tough time stopping that by hand.

Dave

--- In CAD_CAM_EDM_DRO@y..., "ksprayberry428" <kellys@m...> wrote:
> Wohoo! I finally got it!I just backed up and did exactly what
Caudlet
> says below and I found the problem. No Signal. I was trying to use
a
> ISA Parallel port card that was stuck in the computer. I wasn't
> getting anyting from it. I took out that card and tried the other
> port built into the board and it worked. I built my own little
logic
> probe just like you said. I dropped by radio shack on the way home
> and bought the led and a resistor and mounted them on a little
board
> with a terminal block. It worked perfectly.
> Thanks again for the help. I did notice that the motor turned much
> slower than what I thought it would, and I could make it start
> missing steps with my hand. These are 475 iz-in steppers. That
makes
> me curious. I do believe I have a lot of tuning to do.
> Thanks again for all the help!
> Kelly Sprayberry
>
>
>
> >
> > 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.