1 Overview

The DDSF2255 single-phase multi rate energy meter can accurately measure active power in both forward and reverse directions, with the function of recording the maximum active power demand. It can measure and process electricity parameters such as voltage, current, and power in real time, and has functions such as time-sharing control, automatic meter reading, data storage of electricity quantity and demand, recording of the current operating status of the energy meter, and event data recording. It is an ideal intelligent instrument for implementing time-sharing energy measurement and accounting work. The electric energy meter adopts a large screen LCD display and has communication interfaces such as far-infrared and RS485. This instrument is a high-tech product manufactured using advanced ultra-low power large-scale integrated circuit technology and SMT process. The key components are selected from well-known brands of long-life devices, which improves the reliability and lifespan of the product.

According to the standard

This product complies with GB/T 17215.321-2008 Level 1 and Level 2 Static AC Active Energy Meters, GB/T 15284-2002 Special Requirements for Multi Rate Active Energy Meters, JJG596-2012 Verification Regulations for Electronic Energy Meters, DL/T 614-2007 Multifunctional Energy Meters, and DL/T 645-2007 Multifunctional Energy Meter Communication Protocol.

3 Working principle

The working principle of DDSF2255 single-phase multi rate energy meter is shown in Figure 1. When the electric energy meter is working, the voltage and current are sampled separately by the sampling circuit, and then sent to the dedicated electric energy chip for processing, and converted into digital signals to be sent to the CPU for calculation. Due to the use of dedicated energy processing chips, the voltage and current sampling resolution has been greatly improved, and there is enough time to measure energy data more accurately, thereby significantly improving the measurement accuracy of the energy meter. The CPU in the figure is used for time-sharing billing and processing various input and output data. It reads out the data from the dedicated energy chip through a serial interface and completes the time-sharing active energy metering and maximum demand metering functions according to the pre-set time period. It displays various data as needed, communicates and transmits through infrared or 485 interfaces, monitors operating parameters, records and stores various data

4 Technical indicators
4.1 The specifications are shown in Table 1 below (can be customized according to specific user needs):

type name	class leave	Reference voltage Un	Rated current Ib	Active pulse constant
DDSF2255	single phase	220/380V	5（20）A、10（40）A	3200imp/kW.h

Table 1 Specification Table of Single phase Multi rate Active Energy Meter

4.2 Electrical parameters are shown in Table 2:

Operating Voltage	0.8Un～1.1Un
Extreme working voltage	0.7Un～1.2Un
Voltage line power consumption	≤
1.5W and 5VA	Power consumption of current circuit
＜1VA	Data backup battery voltage
3.6VDC	Data backup battery voltage

3.6VDC

Table 2 Electrical Parameters of Single phase Multi rate Active Energy Meter

4.3 The working parameters of the rate are shown in Table 3:	Clock accuracy
	± 0.5 seconds/day (23 ℃± 2 ℃)
± 25 seconds/month (-20 ℃~50 ℃)	Battery capacity
1.2Ah	Data retention time after power outage

≥ 10 years (using new batteries)

Table 3 Operating Parameters of Single phase Multi rate Active Energy Meter Rate

4.4 Climate conditions are shown in Table 4:	Normal operating temperature-20℃
～+50℃	working temperature limit-30℃
～+60℃	Storage and transportation temperature-40℃
～+70℃	Storage and working humidity

≤ 85%

Table 4 Climate Conditions for Single phase Multi rate Active Energy Meter

4.5 Technical parameters are shown in Table 5:	accuracy class
Level 2.0	Rated frequency
50Hz	starting current
Active power 0.002In (mutual inductance type), 0.004Ib (direct type)	shunt running
Designed with anti creep logic	External dimensions270mm′150mm′
77mm	weight
About 1.5kg	4
Number of rates	12
Number of time periods	Measurement range
0～999999.99kW.h apparent	show
liquid crystal	Baud rate
1200bps	Communication ProtocolDL/T645-2007 Multi functional Energy Meter Communication Protocol， 《

Zhejiang Province Single and Single Phase Electronic (Time Division) Energy Meter Communication Protocol (Trial) (V3.0)

5 Outline drawing

Opening the top cover, there is a battery slot in the lower right corner of the watch. Opening the small cover reveals the battery slot, which is equipped with a 3.6V lithium battery for power outage wake-up display.