At present, the cable laying is divided into two types: nameless laying and concealed laying. Concealed laying refers to the unified consideration of electromagnetic flowmeter and other industrial control instruments in the design of the plant, and the steel pipes for laying cables are embedded in the cement floor and walls in advance. Then use threading method to lay the cable in the steel pipe. Sometimes it is also solved by combining cable trench with embedded method. There are two methods for open laying. One is to lay the cable along the wall and corner and then penetrate the cable. These methods depend on the specific situation of the site. There are usually two cables between the converter and the transmitter. One is the power line that the converter provides excitation power to the transmitter. One is the signal line from the transmitter to the converter. In order to reduce the interference of AC power supply on signals, signal lines and power lines are required to be laid in two steel pipes respectively, not in one steel pipe at the same time. For kewill electromagnetic flowmeter, a cable for transmitting induction signal of magnetic field compensation coil or output signal of power transformer shall be added between transmitter and converter. At this time, this cable can be laid in the same steel pipe with the excitation power line. The output terminal of the converter output standard DC current shall be short circuited when there is no external load. Otherwise, the converter indicates that the meter is open circuit and has no indication. When external indicating, recording, integrating and control instruments are connected, they should be connected in series. Pay attention to the polarity of DC current, and the specified output load shall not exceed 2 kiloohms.