Underrange and Overrange

ABB Field Information Manager Learning Center

The Check of Underrange and Overrange is a test group allowing the validation of correct status indication within the system for values below and above the defined signal range.

It is only applicable for HART nodes with Signal Type "AI" and connected field device.

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The check of Underrange and Overrange is only applicable for nodes with Signal Type "AI" and connected field device.

Underrange and Overrange test values can be specified in the imported Loop Check Settings or in the Default Loop Check Settings.

If available, the node status received from the system is checked for correct status indication of Underrange and Overrange. If set correctly, the test point is rated as "Passed". Otherwise, it is rated as "Failed". Only if no node status is received from the system, the measured node value is compared against the expected value as in the normal Test Routine.

To ensure that the node status is set correctly, the Underrange value is tested with 0.02 mA below and the Overrange value is tested with 0.02 mA above the defined values.

Test Strategy

  • FIM forces the configured Underrange level - 0.02 mA and the configured Overrange level + 0.02 mA.
  • FIM verifies if the Underflow and Overflow flag is set correctly in node status.
  • If the node status is set, the test point is passed.
  • If the node status is not set, the test point is failed.


  • Ensure that the field device supports the requested Underrange and Overrange values.
    • In most cases, Loop Simulation from 3.6 mA to 23.0 mA has to be supported.
    • Otherwise, the Loop Check for this node will be cancelled.

Priority of defined level values

  • Underrange and Overrange levels can always be configured at node-specific level in Loop Check View which overwrites any settings from pre-configuration.
  • If imported Loop Check Settings are available for the node, the values as defined in the imported file are used to force Underrange and Overrange levels.
  • If no imported Loop Check Settings are available for the node, the default values as defined in FIM Loop Check Settings (Tools Menu > PROJECTS > LOOP CHECK SETTINGS) are used to force Underrange and Overrange level.
  • Underrange and Overrange level values are always defined in electrical form (i.e. 3.8mA or 20.5mA).
  • If the NAMUR NE43 setting is enabled, any specific levels are ignored and the fixed levels according to NAMUR NE43 are used: Underrange level: 3.8mA / Overrange level: 20.5mA.

System Configuration (ABB System 800xA)

  • Configuration of I/O Module for Underrange and Overrange has to be correct.
  • If Underrange and Overrange levels different from NAMUR NE 43 (UR: 3.8 mA / OR: 20.5 mA) shall be used, the setting "NAMUR NE 43" has to be set to "Disabled".
  • Configuration of Underrange Level and Overrange Level according to values from imported Loop Check Settings (i.e. imported CSV file).


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