Functions and features Adopting advanced DSP and FPGA chip, algorithm and sampling technique, DSB-301A is capable of real time and high-speed calibration with extremely high accuracy and powerful functions. With SMT technology applied inside the device, DSB-301A has extremely high reliability. Large LCD display screen is used as the interface with high definition. Special attracted-disc photoelectric sampler is featured with automatic collection of mechanic meter black spots and electronic meter LED signals, eliminating connection to the pulse terminals to collect electronic meter pulse. It is very safe and convenient. Also special pulse sampling line is provided to collect electronic meter pulse. With special precise clip-on CT, it can calibrate watthour meter without dismantlement. We can also use electric wire for connection. With RS232 port, DSB-301A is easy to connect to PC, download field test data. Special DSBMIS fully automatic calibration software is installed on system PC so as to download users' information, read and process field data. And it is very convenient to connect with other networks. The parameters, such as voltage, current, power(apparent, active, reactive), phase, power factor, frequency, etc. can be real-time measured. The real time vector diagram demonstration and harmonics analysis is available. Auto-detection for field wrong wiring:48 types of three phase 3-wire common wrong wiring detection; 96 types of three phase 4-wire wrong wiring detection. 0~31 harmonics analysis, bar graph indicated. Save up to 100 field calibration records with high capacity EEPROM and no data loss for 10 years.