-2

Overlap Error

Allen-Bradley · MicroLogix 1400 Programmable Controllers

What does -2 mean?

An output overlap is detected, meaning multiple functions are assigned to the same physical output. This is a configuration error (e.g., PTO0 and PTO1 attempting to use a single output) that causes the controller to fault, and the User Fault Routine does not execute.

Common Causes

  • Two or more PTOX instructions configured to use the same physical output.
  • Conflicting output assignments for different controller functions (e.g., PTOX and a discrete output) inadvertently using the same terminal.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Review the PTOX instruction configuration for all PTOX instances (e.g., PTO0, PTO1) and verify that each is assigned to a unique physical output.

  2. 2

    Check for any other controller functions that might be inadvertently assigned to the same physical output as a PTOX instruction.

  3. 3

    Modify the program to ensure each physical output (e.g., Output 2, 3, or 4) is used by only one instruction at a time.

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Verified technical data. Last updated: March 2026

Related Faults

Source: Allen-Bradley MicroLogix 1400 Programmable Controllers
Allen-Bradley Error -2: Overlap Error — Troubleshooting Guide | ErrorLib