-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
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
Check for any other controller functions that might be inadvertently assigned to the same physical output as a PTOX instruction.
- 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.
Verified technical data. Last updated: March 2026
Related Faults
Source: Allen-Bradley MicroLogix 1400 Programmable Controllers