-3

Undefined Accel/Decel

Allen-Bradley · MicroLogix 1400 Programmable Controllers

What does -3 mean?

This error occurs when Acceleration Count and Deceleration parameters are not defined during the transition to Run mode, specifically when the Accel/Decel Pulses Independent (ADI) bit is set (1) in the PTOX configuration. This is a configuration error preventing proper motion control.

Common Causes

  • Acceleration Count and Deceleration values are not configured or set to zero when the ADI bit is set to 1.
  • Incorrect sequence of enabling PTOX with ADI where parameters are not initialized before Run mode.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Ensure that Acceleration Count and Deceleration values are properly defined and non-zero in the PTOX configuration before entering Run mode when the ADI bit is set (1).

  2. 2

    Review the PTOX instruction parameters in the programming software to ensure all required acceleration and deceleration values are explicitly set.

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Verified technical data. Last updated: March 2026

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Source: Allen-Bradley MicroLogix 1400 Programmable Controllers