PLC Scan Time Calculator

Calculate total PLC scan time and maximum scan frequency from input, program, output, and overhead times.

Input Scan Time (ms)

Program Execution Time (ms)

Output Scan Time (ms)

System Overhead (ms)

How to Use the PLC Scan Time Calculator

Enter the input scan time from the PLC datasheet or measurement (ms).
Enter the program execution time based on instruction count (ms).
Enter output scan time and system overhead, then click Calculate.

Anwendungsfälle

•Verifying PLC response time for safety systems.
•Optimising scan times for high-speed conveyor control.
•Sizing PLC hardware for demanding control applications.

Formel

Scan Time = Input Time + Program Time + Output Time + Overhead. Max Frequency (Hz) = 1000 / Scan Time (ms).

Häufig gestellte Fragen

What is PLC scan time?

PLC scan time is the time for one complete cycle: reading inputs, executing the program, writing outputs, and housekeeping. Faster scan times allow faster process response.

What is a typical PLC scan time?

Simple PLCs scan in 1–10 ms. High-speed motion controllers may scan in under 1 ms. Large programs or many I/O points increase scan time.

Is this calculator free?

Yes, all OhMyCalc calculators are completely free to use.