Rockwell Automation 1715-OF8I Redundant I/O System User Manual - Manual (Page 274)

274 Rockwell Automation Publication 1715-UM001C-EN-P - March 2014
Appendix C 1715-IB16D Digital Input Module Diagnostics
For a full-diagnostics setting configuration, use these resistor values.
None Diagnostics Configuration
Selecting None in the Diagnostics pull-down menu loads a different set of default
values into the threshold settings. This is selected when no EOL devices are
used.
Figure 73 - None Diagnostics Threshold Default Values
Based on these settings, if the switch is closed, the input reports an ‘on’ condition
anytime the voltage is above ~14.5V, but does not report a short circuit, because
there is no way to get the voltage to rise to 32V.
The same is true with an ‘off ’ condition. The module reports an ‘off ’ condition
anytime the voltage is below ~5.5V, but does not report a wire off, because it has
to go below 0V to do so.
IMPORTANT These are the most common commercially-available EOL devices.
Table 60 - Full Diagnostics Resistor Values
Item Value
R1 15 k(1%) - power 0.5 W (max power dissipated 0.128 W)
R2 3.9 k(1%) - power 0.5 W (max power dissipated 0.128 W)
Loop supply voltage= 24V DC (±10%)
Indicates An
‘On’
Condition
Below 5.5V
Causes An ‘Off’
Condition