1, in order to distinguish between the main circuit and control circuit, the main circuit in the drawing circuit (motor, electrical and connecting lines, etc.), with thick lines, while the control circuit (Electrical and connecting lines, etc.) with a thin line. It is customary to place the main circuit on the left (or upper) of the circuit diagram and place the control circuit on the right (or lower).
2, power circuit, control circuit and signal circuit should be drawn:
Power circuit - power circuit drawing horizontal line; the electric power equipment (such as electric motors, etc.) and other protection electrical branch, should be vertical power circuit draw.
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 of the electrical appliances are not in accordance with the actual layout of the situation on the line, but the use of the same electrical components were painted in 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 function of electrical appliances are used to indicate a certain number.
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. If the contactor and the electromagnetic relay are not absorbed on the position of the electromagnet, the stroke switch, the button and the like are not pressed.
6, in order to check the 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 the line of the side (left or right).
7, for the cycle of the movement of the body, should be given work cycle diagram, universal switch and stroke switch should draw the action program and action position.
8, schematic should be marked with the following data or instructions:
Voltage value, polarity or frequency and phase number of each power supply circuit.
The characteristics of some components (such as resistors, capacitors, etc.);
Operating methods and functions of non - used electrical appliances (such as position sensors, manual contacts, solenoid valves, pneumatic valves, timers, etc.).