Underrange/Overrange Detection

Underrange/Overrange Detection detects when signal is operating beyond limits set by the input range.
The module can read input signal levels outside the low and high signal values for each input range. The signal limits to which the module can read are thresholds. Only when the signal is beyond a threshold is an underrange or overrange condition that is detected and indicated.
For example, if you configure a 5034-IF4IH module channel to use the + 10V input range, an overrange condition does not exist until the input signal exceeds 10.70V.
The module has deadband values for each range. The deadband lets a condition remain set despite it disappearing. For example, if a module uses a Current input type in the 4…20 mA range and the signal value goes below 3 mA, the underrange condition is triggered. Because of the 0.07 mA deadband, the condition is not cleared until the signal value reaches 3.07 mA. See Alarm Deadband for more information.
The following table lists the input ranges of the input modules and the thresholds in each range before the module detects an underrange/overrange condition.
Input Signal Threshold Ranges - 5034-IF4IH
Input Type
Range
Underrange Threshold
Uncertain Threshold
Overrange Threshold
Low
High
Current (mA)
0…20 mA
Not Applicable
Not Applicable
20.633 mA
23.00 mA
4…20 mA
3 mA
3.667 mA
20.633 mA
Voltage (V)
-10...+10V
-10.7V
-10.5V
+10.5V
+10.7V
0…5V
Not Applicable
Not Applicable
+5.25V
+5.35V
0…10V
Not Applicable
Not Applicable
+10.5V
+10.7V
IMPORTANT:
The Disable All Alarms feature does not disable the Underrange/Overrange Detection feature but it disables alarms on the module.
Underrange/Overrange detection is not an alarm. It is an indicator that channel data has gone beyond the maximum or minimum threshold, respectively, for the channel range.
To disable the Underrange/Overrange Detection feature, you must disable the channel.
Underrange/Overrange conditions are indicated when the following tags change to 1:
  • I.Chxx.Underrange
  • I.Chxx.Overrange
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