I.Chxx.RateAlarm

Input Rate of Change Alarm

Allen-Bradley · Compact 5000 I/O Analog Modules

What does I.Chxx.RateAlarm mean?

This tag, when set to 1, indicates that the rate of change between input samples for channel xx has exceeded the configured Rate Alarm Limit (in Engineering Units per second). If the Rate Alarm latching feature is enabled, the alarm will remain active until manually unlatched, indicating an unexpected or excessively rapid change in the input signal.

Common Causes

  • The physical input signal is changing at a rate faster than the configured Rate Alarm Limit.
  • The Rate Alarm Limit parameter is set too low for the expected dynamics of the process signal.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Observe or log the input signal's rate of change for channel xx to confirm it exceeds the limit.

  2. 2

    Review and adjust the Rate Alarm Limit setting in the module configuration to an appropriate value for the application's dynamics.

  3. 3

    If the alarm is latched, set the O.Chxx.RateAlarmUnlatch tag to 1 in the Logix Designer application after the triggering condition has returned below the limit.

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Verified technical data. Last updated: March 2026

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