Functions and features With special aluminum alloy housing, the device has firm and nice appearance. It is easy to operate and transport with light weight. Single phase power supply is convenient for users with various occasions. It has multiple protection system with high speed response, that makes the device more reliable. Also it has sound and light warning unit. Equipped with special keyboard, the device can indicate automatically the united unit and separated unit phase characteristics of all kinds of meters during user's manual verification, and it is more convenient. As required by the protocol, automatic test can be carried out on watthour meter's startup, creeping, fundamental error, standard deviation, 8-hour and 24-hour variation. High current output£¨0~100A£©, convenient for calibration of high current watthour meter. Impact test on watthour meter's voltage imbalance, frequency, harmonics , negative phase sequence, etc. It can test watthour meters with different constant, and correct the constant. Special junction box is employed to short circuit automatically in open circuit. Special photoelectric sampler is featured with automatic collection of mechanic meter black spots and electronic meter LED signals. Photoelectric head reverses by itself, easy to disassemble and assemble. Special pulse sampling interface and high voltage isolating circuit are adopted to avoid wrong switchin of high voltage. Meter running test can be performed according to KWh, time or pulse number. The real-time parameters, such as power, voltage, current, phase, power factor, frequency, etc. can be measured. The real time vector diagram can be displayed also. All types of bar code input is acceptable. With RS485 port, it is very convenient to connect with all kinds of foreign and domestic watthour meters. Automatic detection of communication protocol function is available. The communication protocol complies with all stipulations of DL/T645-1997 and IEC1107, and it can be modified as user's requirement. It has clock reference and GPS clock.