A counter is a logic circuit that counts input signals such as clocks, etc. It has a function to count and display input signals. It is used for maintenance and management of machine tools, various control panels, compressors, etc., and for counting shipments, vehicle numbers in parking lots, etc. Some devices have a built-in lithium battery, etc. that save power and have a long life. There are preset counters, total counters, etc. When the preset type reaches the set value, the control output works and the next output starts. The total type has no control output function and displays the measured value. Some have high visibility, others have space-saving features that can be used in small environments. In addition, there are devices that have excellent safety, environmental resistance such as water resistance and oil resistance, and impact resistance, and you can select a product for the operating environment.