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Rockwell Automation Publication 1756-UM540E-EN-P - December 2017
51
1756-IF8I Isolated Analog Input Module
Chapter 3
Wire Off Detection
The 1756-IF8I module alerts you when a wire is disconnected from a channel or
the RTB is removed from the module. The following events occur when a wire
off condition exists:
•
Module Operating in
Voltage Mode
–
Input data for that channel changes to a specific scaled value
corresponding to the Overrange value.
–
The Overrange bit is set in the
I:Ch[x].Overrange
tag.
•
Module Operating in
Current Mode
–
Input data for that channel changes to a specific scaled value
corresponding to the Underrange value.
–
The Underrange bit is set in the
I:Ch[x].Underrange
tag.
•
A fault bit is set in the owner-controller that can indicate the presence of a
wire off condition.
Because the module can be used in voltage or current applications, differences
exist as to how a wire off condition is detected in voltage or current applications.
IMPORTANT
Be aware that the Disable All Alarms feature, does not disable the wire off
detection feature. The Disable All Alarms feature disables all alarms on the
module.
The wire off detection feature is not an alarm. It is an indicator that a wire
has been disconnected from the channel but does not trigger an alarm.
To disable the wire off detection feature, you must disable the channel.
Table 10 - 1756-IF8I Module - Wire Off Conditions in Different Applications
Application Configuration
Wire Off Condition Cause
Resulting Module Behavior
Voltage Applications
Either of the following:
•
A wire is disconnected from
the module.
•
The RTB is disconnected from
the module.
•
Input data for that channel changes to the scaled value associated with the
overrange
signal value of the
selected operational range.
•
The
I.Ch[x].Overrange
(x=channel number) tag is set to 1.
Current Applications
•
Input data for that channel changes to the scaled value associated with the
underrange
signal value of the
selected operational range.
•
The
I.Ch[x].Underrange
(x=channel number) tag is set to 1.
Содержание 1756-IF8I
Страница 8: ...8 Rockwell Automation Publication 1756 UM540E EN P December 2017 Table of Contents Notes ...
Страница 40: ...40 Rockwell Automation Publication 1756 UM540E EN P December 2017 Chapter 2 Analog I O Module Features Notes ...
Страница 180: ...180 Rockwell Automation Publication 1756 UM540E EN P December 2017 Chapter 9 Troubleshoot Your Module Notes ...
Страница 216: ...216 Rockwell Automation Publication 1756 UM540E EN P December 2017 Appendix C 1492 Analog Interface Modules Notes ...
Страница 222: ...222 Rockwell Automation Publication 1756 UM540E EN P December 2017 Index Notes ...
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Страница 225: ...High Resolution Analog I O Modules User Manual ...
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