(1) Function of buttons

A button is a control switch that is operated by applying force from a certain part of the human body (usually a finger or palm) and has a spring energy storage reset function. It is the most commonly used master electrical device. The current allowed to pass through the contact of the button is relatively small, generally not exceeding 5A. Therefore, in general, it does not directly control the on/off of the main circuit (high current circuit), but sends command signals in the control circuit (low current circuit) to control contactors, relays and other electrical appliances, and then they control the on/off, function conversion or electrical interlocking of the main circuit.

2) The structural principles and symbols of buttons

A button generally consists of a button cap, a reset spring, a bridge type moving contact, a stationary contact, a support rod, and a housing.

The opening and closing states of the contact when the button is not subjected to external force (i.e. static) are divided into stop button (i.e. dynamic breaking button), start button (i.e. dynamic closing button), and composite button (i.e. button that combines dynamic closing and dynamic breaking contact into one).

When the button is subjected to external force, the opening and closing state of the contact changes

(3) Button structure form code

K - Open type, embedded on the operation panel;

H - protective type, with a protective shell, can prevent internal parts from being mechanically damaged or accidentally touched by people with live parts;

(4) Model and meaning of buttons

S - Waterproof, with a sealed shell to prevent rainwater from entering;

F - anti-corrosion type, can prevent corrosive gases from entering;

J - Emergency type, with a red mushroom button (protruding outside), used for emergency power cut-off;

X - rotary knob type, operated by rotating the knob, with two positions: on and off;

Y - Key operated, operated by inserting a key, can prevent accidental operation or be operated by a dedicated person;

D - cursor button, equipped with a signal light inside, also serves as a signal indicator.

(5) Selection of buttons

1) Select the type of button based on the usage scenario and specific purpose. For example, the buttons embedded on the operation panel can be of the open type; Select cursor type for displaying work status; Key operated equipment should be used in important areas where personnel should be prevented from misoperation; Corrosion resistant materials should be used in areas with corrosive gases.

2) Select the color of the button based on the work status indication and work requirements. For example, the start button can be selected in white, gray, or black, with white being preferred or green being preferred. The emergency stop button should be selected in red. The stop button can be selected in black, gray, or white, with black being preferred or red being optional.

3) Select the number of buttons according to the needs of the control circuit. Such as single button, double button, and triple button.