3
Frequency Error
Allen-Bradley · MicroLogix 1400 Programmable Controllers
What does 3 mean?
The operating frequency value (OFS) specified for the PTOX instruction is less than 0 or greater than 100,000 pulses per second. This error faults the controller and indicates an invalid frequency parameter. It can be cleared by logic within the User Fault Routine.
Common Causes
- Operating frequency (OFS) parameter set to an out-of-range value (i.e., less than 0 or greater than 100,000).
- Incorrect calculation or direct input of an invalid frequency parameter in the PTOX instruction.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Adjust the operating frequency (OFS) value in the PTOX instruction to be within the valid range of 0 to 100,000.
- 2
Review the program logic that writes to the OFS parameter to ensure it calculates and sets a valid frequency.
- 3
Clear the fault using the User Fault Routine or by cycling power after correcting the OFS value.
Verified technical data. Last updated: March 2026
Related Faults
Source: Allen-Bradley MicroLogix 1400 Programmable Controllers