Rockwell Automation 1715-OF8I Redundant I/O System User Manual - Manual (Page 281)

Rockwell Automation Publication 1715-UM001C-EN-P - March 2014 281
1715-IB16D Digital Input Module Diagnostics Appendix C
Calculate On/Off Condition for Resistor Values
If a threshold value is set and we wanted to figure out which resistors to use, we
can follow these examples.
On Condition
For an on condition, use the following formulas.
In this case, the module load is 5.1 kand the supply voltage is assumed to be
24V DC. So, for this example, use Figure 77 and choose 13V DC, because it is a
value within the range in the threshold tables.
Figure 77 - On Condition
Shield
(if used)
Terminal
Blocks
OV
20 Ω
100 Ω
50 mA
4.99k Ω
Termination
Assembly
+24V dc
R1
R2
45678
5.1K
Module
Resistance
SW1