Subject: From: Date:

Prairie Digital Model 40 Dan Carrington Fri, 12 Feb 1999 10:48:54 -0800

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	Ok, I finally pulled my model 40 setup out and cut the jumper on my
relay board that enabled the 8 analog inputs and gave me back the 4
Digital's that were used for the data of the analogs.  Now, when setup
as analogs, I also had three other digital i/o channels that did not
work correctly.  Two of them also came back to useful digital I/O's, but
the third still has +5 volts on it.  I don't know why, but I can live
with that.  
	Something else to note.  The digital inputs do not have much "bleed
down" as a way to term it.  If you supply 5 volts from the model 40 +5v
output to one of the inputs it immediately becomes "low".  If you remove
the +5v from the input, it takes anywhere from 5 to maybe 30 seconds to
become "high" again.  The voltage is staying on the sensor collector and
is not bleeding back to ground.  The way around this is to install a
resistor between the digital input and the model 40 ground.  The input
then returns to "high" immediately after removal of the +5v to it.  This
is slightly annoying in the wiring as you will need to install a
resistor onto every digital I/O that is used as an input.  The outputs
work fine as they switch +5v out of themselves.  Anybody else use one of
these things and know why pin #29 (digital I/O #28) has 5 volts on it
when I am telling ECS to use it as an input and therefor it should not
have any voltage on it?

Dan Carrington

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