Measurement Computing CIO-DO24DD - Manual (Page 13)

4.7 CLAMPING VOLTAGE INPUT
The output transistors can be set to clamp voltage spikes and prevent them from
damaging your circuit. For example, if you are switching a 9V circuit, connect the
9V to the clamp input as well. This will hold transient voltages to less than 11V (9V
+ 2V max forward voltage across the clamping diode at 350mA).
4.8 TEST CONNECTIONS
The CIO-DO24DD is a digital switching device. To test the installation and the board
you will need a kno wn working circuit to switch, such as a lamp bulb and battery
described previously.
After you have the circuit connected, the TEST option of the InstaCal program can be
used to produce an alternating on/off signal at the switch.
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