What Is a Thumbwheel Switch?
A thumbwheel switch is a device used for settings that convert the ON/OFF signals of multiple contact circuits into binary, decimal, hexadecimal, or other codes. This conversion is achieved by turning a disc-shaped part known as a rotor. The switch is sometimes referred to as a digital switch or thumbwheel switch.
There are two main types of thumbwheel switches: rotary switches, operated by rotating the switch with a finger, and push switches, activated by pressing a button.
Some thumbwheel switches come with a lock function to prevent accidental changes to the set value, requiring a thin pen nib for operation.
Uses of Thumbwheel Switches
Thumbwheel switches vary in size, with smaller switches typically used in office equipment and consumer electronics, and larger ones in industrial equipment and machine tools.
In industrial equipment and machine tools, these switches are utilized to set operational control values such as time, temperature, and number of cycles. In machine tools, they are used to set dimensional limits for machining, and in motor control, to set microstep counts.
They are also employed in various measuring instruments for setting measurement conditions like frequency, temperature, and time.
Principles of Thumbwheel Switches
Thumbwheel switches consist of simple components such as a case, slide, rotor, sealing plate, packing, printed circuit board, mounting plate, and, for push-operated models, a push button. They are versatile and used in a wide range of applications.
The selected number is visually confirmed on the switch, reducing the likelihood of incorrect inputs. Mistakes can be easily corrected, adding to the usability of these switches.
Since a mechanical mechanism is used for code conversion, the set value remains preserved even during power outages. This mechanical nature also simplifies the circuit and wiring requirements on the output side, enhancing both reliability and maintainability.
Thumbwheel switches are particularly effective in applications where parameters need frequent adjustments according to operating conditions. While many modern systems use large-screen operation panels for parameter settings, there are still numerous instances where hardware-based setting changes are necessary in field conditions.