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Rockwell Automation Publication 1756-UM013B-EN-P - October 2019
Chapter 3
1756-IB16S Input Module Features
Figure 7 - 1756-IB16S Test Pulse in a Cycle
On the 1756-IB16S module, the test pulse width (X) is less than 600 µs; the test
pulse period (Y) is less than 100 ms.
When the external input contact is closed, a test pulse is output from the test
output terminal to diagnose the field wiring and input circuitry. By using this
function, short-circuits between inputs and 24V power, and between input signal
lines can be detected.
Figure 8 - Short Circuit Between Input Signal Lines
OUT
X
Y
On
Off
24V DC
TO0
IN 0
IN +
COM
IN 1
TO1
24V DC
0V DC
External Contact
External Contact
Short circuit between input signal
lines and power supply (positive side)
Short circuit between channels 0
and 1.