The E-series product is a multifunctional power instrument with programmable measurement, display, digital communication, and power pulse transmission and output functions. It can complete power measurement, energy calculation, data display, collection, and transmission, and can be widely used in substation automation, distribution automation, intelligent buildings, and internal power measurement, management, and assessment of enterprises. The measurement accuracy is 0.5 or 1 level, achieving LED/LCD on-site display and remote RS-485 digital interface communication, using MODBUS-RTU communication protocol.