-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
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
Review the PTOX instruction parameters in the programming software to ensure all required acceleration and deceleration values are explicitly set.
Verified technical data. Last updated: March 2026
Related Faults
Source: Allen-Bradley MicroLogix 1400 Programmable Controllers