What is minimum scan time in PLC?

PLC minimum scan time

1 Like


In a Programmable Logic Controller (PLC), the scan time refers to the time taken by the PLC to read the status of its inputs, run its program, and update its outputs. This process is known as a “scan cycle” and the PLC repeats this cycle continuously while it is in operation.

Scan Time in PLC

The minimum scan time is the shortest time in which a PLC can complete one scan cycle. This parameter is heavily dependent on the specific model of the PLC and the complexity of the program it is running. In some high-performance PLCs, this could be in the range of a few milliseconds, while others may take a few tens of milliseconds.

It’s important to note that the actual scan time in a real-world application might be longer than the minimum scan time due to factors such as the length and complexity of the program, the number and type of inputs and outputs, communication delays, and other factors.

As an end-user, you generally don’t have control over the minimum scan time but you can optimize your program to ensure it runs efficiently and doesn’t unnecessarily lengthen the scan cycle. If you have specific real-time requirements for your process, you should select a PLC that can comfortably meet those needs with some margin for safety.strong text