A Counter is a device that counts the number of objects or the number of operations. It is called a Counter because it counts the number of ON/OFF signals input from an input device, such as a switch or sensor.

It is fairly simple for people to count ten or twenty objects, but larger numbers make counting increasingly difficult. Counters outperform people when it comes to counting accurately.

There are 2 types of classifications: 

A Preset Counter counts until the present value reaches a preset value, and then it activates a control output to operate an output device. The term preset in Preset Counter means that you can set a value in advance.

A Total Counter does not output a control signal. It only displays the present value. It is often used when you only have to display a production count, for example, number of puddings counted.