OP7200 & Digital Input

Using a 3 KHz square wave from 0-15V CMOS as inputs.
Digi In 0-7 are fine.
Digi In 8-15 is not (seemingly dead.)
Digi In 16-18 are fine.

This is comfortably with in the +/- 36 VDC limits.

I will not even mention how much time this has cost me :wink: Um, OK. Glad you asked. Let’s just say a lot !!

Either there is some configuration parameter I have missed OR something is toast. This is pretty obvious from the 8 good/8 bad/3 good picture.

I’ll also try to figure out how to email “support” with this.


You can email support directly at support@rabbit.com or you can fill in the online form located at

i agree with Margaret, you should post your queries to support@rabbit.com

You might want to check the jumpers on the board:
JP3 IN8�IN15
pins jumpered
1�2 Pulled up to Vcc �
2�3 Pulled down

check the users manual, page 133 located at

The basic problem is solved. Or at least it vanished while chasing down certain things I was certain I had tried. And my 3 KHz 15V CMOS square waves are being seen perfectly. Although there is some worry about the guaranteed 0 voltage requirement for IN8 - IN15 (see below) so I have now connected the CMOS gate stuff into IN8 - IN15.

It is worth noting in the forum that the various banks of digital input are quite different from each other (as fully documented on page 20 of the OP7200 users manual. Thanks Rabbit.)

A guaranteed 0 is:
1.5 V for IN0 - IN7
0.8 V for IN8 - IN15
0.8 V for IN16 - IN17

A guaranteed 1 is:
3.5 V for IN0 - IN7
2.0 V for IN8 - IN15
3.5 V for IN16 - IN17

IN0 - IN15 have an access time of 5 usec.
IN16 - IN18 have an access time of 100 Usec !!


for what it is worth . . .

I posted the details of the differences between the three banks of digital inputs on the OP7200 in order to share this information. Others might have the same problem. Or at least need to know this detail. I go to support@rabbit.com if there is no answer from the forum. :smiley: