Re: [CAD_CAM_EDM_DRO] No movement

Roy J. Tellason wrote:

>Measuring voltages there isn't going to be nearly as helpful as knowing what's
>going on. For those step and dir pins, particularly. I realize that a
>scope isn't exactly a trivial matter to acquire, but maybe a logic probe?
>Maybe build something simple? There are schematics out there, I'm sure...
>
>That 1.56 volts in particular doesn't sound like a valid logic level but might
>be what a voltmeter would say if it were looking at a train of pulses. Try
>the meter on AC instead of DC and see how the reading changes, that might
>tell us something.
>
>

A very simple Gecko simulator can be made with an LED and a resistor.
Connect the
+5 to a 270 Ohm resistor (actually anything between 120 and 1000 Ohms
should work).
Connect the other end of the resistor to the positive terminal of the
LED (almost always
the longer lead). Connect the other lead of the LED to the circuit to
be tested.
When that circuit is driven LOW (to ground or logic zero) the LED should
light.
When the circuit is not driven at all (high impedance) or driven to +5
V, the LED
will be dark. Very short high pulses with the circuit normally low in
between the
pulses will probably not be noticeable. Short low pulses while
otherwise high can
often be seen as a faint flicker. This circuit also simulates the input
circuit of a
Gecko 201A or 320 drive (or the other Geckos when set for common +).

Jon