1. In order to distinguish between the main circuit and the control circuit, the main circuit (motor, electrical appliance and connecting wire) is represented by coarse line when the circuit diagram is drawn, and the control circuit (electrical appliance and connecting wire) is represented by a thin line. It is customary to place the main circuit on the left (or upper) side of the wiring diagram and place the control circuit on the right (or lower) side.
2. the power circuit, control circuit and signal circuit shall be plotted separately:
Power circuit - power circuit, draw horizontal lines, power equipment (such as motors, etc.) and other protective appliances, should be drawn from the vertical power circuit.
Control circuit and signal circuit should be vertically drawn in the two level power line between the dissipative element (such as coil, electromagnet, signal lamp etc.) should be directly connected at the level of the power ground or below the line, and the control of the contact connection between the dissipative element above the horizontal line.
3. In the schematic diagram, each appliance is not drawn on the line according to its actual layout, but the components of the same electrical appliance are drawn at the place where they are completed.
4. for the type and function of the electrical control circuit of the difference, said each appliances and their components with some graphic symbols, and for each appliance has a symbol, all parts belonging to the same electrical appliances (such as contactor coils and contacts) are expressed with the same text symbols. The same electrical appliances are represented by a certain number of serial numbers.
5. because of various appliances for different action respectively in different working stages, when the contacts open and close, in principle only said a plan, therefore, the provisions of all electrical appliances that contacts the normal position, namely all kinds of electric coil is not energized or not for the position of mechanical. For example, for contactors and electromagnetic relays, where the electromagnet is not sucked, the position of the switches, buttons, etc. is not pressed.
6. in order to check line convenience. To make a dot at the connection between the electrical principle diagram two above the wire, and each point to a number, number of the principle is: close the left power line with the singular mark, close to the right side power line with dual labeling, usually in the electrical coil or resistor as the dividing line between single or dual therefore, the electrical coil or resistor should be placed in each side (left or right).
7. The working cycle diagram should be given to the mechanism with circular motion. The universal switch and stroke switch should be drawn the action program and action position.
8. schematic diagrams should be marked with the following data or instructions:
Voltage, polarity, frequency, and phase of each power circuit.
Characteristics of some components (such as resistors, capacitors, parameter values, etc.);
The operating methods and functions of the less commonly used electrical appliances (such as position sensors, manual contacts, solenoid valves or pneumatic valves, timers, etc.).