Switch / Relay On Digital Input; Ttl/Cmos Signal On Digital Input - Intab PC-Logger 2100 User Manual

5.1

Switch / Relay on Digital Input

NO or NC contact devices for status indication or counting are best connected as
shown below.
If need be, you can debounce switches by connecting a capacitor externally. (See
dashed capacitor in the figure above.) A 0.1uF capacitor will give a time
constant of 10 milliseconds, 1uF increases the time constant to 100 milliseconds
and 10uF to about 1s.
Contact bounces usually die down within 100ms but may last longer than 200ms
if contacts are extremely bouncy.
5.2

TTL/CMOS signal on digital input

TTL and CMOS signals are easily connected. No special interface is needed. Just
make sure that the signal grounds of the two systems interconnected this way are
also connected.
Make sure that all signals are below the absolute maximum of 20V.
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