International Standard Edge Computing Energy Acquisition

With the deepening adjustment of the modern industrial structure, the reduction of consumption and energy conservation, the continuous promotion of low-carbon and environmental protection, the demand for intensive and intelligent energy management is increasingly prominent. However, the traditional meter reading is still time consumption, with low efficiency, high labor cost and unguaranteed accuracy, which will be unable to meet the current needs.

Based on the nearly 20 years experience in the field of electric data acquisition and the latest achievements of IoT technology application, we design international standard edge computing energy acquisition: Acquisition unit Ⅱ(LoRaWAN wireless).

The acquisition unit II is independently developed by us,following Q/GDW-2013 State Grid Corporation Standard. With micro power wireless to be the communication medium, the acquisition unit uses LoRa modulation technology, and follows LoRa WAN wireless transmission protocol, to realize wireless communication mode of local RS485 centralized data acquisition and transmission of electric meter.. Having the outstanding features of ultra-long distance transmission, strong anti-interference ability and convenient to use, the acquisition unit can be used along with LoRaWAN gateway to achieve data transmission, monitoring and intelligent management. Up to now, it is widely used in data acquisition field of electric power acquisition system.

       The acquisitionunit follows the protocol of DL/T 645-1997 multifunctional electric meter, DL/T 645-2007 multifunctional electric meter communication protocol, and Q/GDW 1375.3-2013 specification of electric information acquisition system for power users: specification of acquisition unit.The acquisition unit is convenient and simple to use. As long as the terminal node has an RS485 port and is connected to the acquisition unit, the acquisition unit communicates wirelessly with the gateway through LoRaWAN to achieve point-to-point data collection. The gateway uploadsdata to the background system to complete remote control of the terminal equipment.The acquisition unit can communicate with any gateway that complies with LoRaWAN international standards.

 Acquisition unit graphic guidance(take electric meter as an example)

Main Functions

•  Diverse data acquisition, convenient remote control of the background

       Able to collect the data of current, voltage and electric quantity of electric meter to analyse electric load, power supply quality and three-phase unbalance. It can also be used for data acquisition of other metering equipment, flow meter and sensing equipment.

•  Multiple downlink channel with low cost

        One acquisition unit can connect up to 32 terminal nodes on the downlink, which greatly saves the number of acquisition devices and reduces the input cost.

•  With power cut event report function

       In case of abnormal electricity consumption,  the system will automatically issue an alarm, and the management personnel can find the specific fault line through the background system, so as to facilitate the dispatch of maintenance personnel to the site in time for troubleshooting.

•  Encryption management and data transmission

       With a unique secret key to prevent malicious attacks, it can automatically transmit the data to the target node device according to the LoRaWAN communication protocol.

•  Wireless communication rate adaptation.

        Under the condition of short communication distance, the server improves the rate of the node through the algorithm, and the node interacts with the server according to the communication rate configured by the server, which improves the rate of data acquisition and channel capacity.

• With conflict avoidance function

       Through listening to the current micropower wireless channel whether there is any equipment sending data, the node can decide data transmission mode. Immediately send data on the current channel when there is no data transmission, or immediately switch channel again to detect whether there is any devicesending data, until vacant device is detected immediately to send data, which will lower the wireless conflict at the same time to promote the communication nodes of real-time response ability.

• Support parameter backup and off-line monitoring

       Automatically save wireless and LoRaWAN communication parameters，restore power loss and prevent the device to reconnect to the network capacity after power failure restart. The network drop detection strategy is provided to prevent the long-term failure of communication between nodes.

    Operating Principle

      Introduction to operating principle：

      The power supply circuit converts AC 220V voltage into the voltage values required by the acquisition unit. The communication circuit of 485 interface realizes the communication between the acquisition unit and the smart electricmeter. The infrared handheld meter reading machine can manage and debug the acquisition unit through the infrared communication interface.Impedance matching filter circuit provides good RF impedance matching and filtering to ensure maximum power transmission and improve the efficiency of RF signal. RF transceivers complete the modulation, demodulation and amplification of RF signals.The MCU is responsible for the implementation of the LoRaWAN protocol and the transmission of data to and from the meter.

    Technical Parameter

• Electric parameter

  Operating parameters	Operating power supply	AC 220V±20%
  	Operating temperature	－40℃～70℃
  	Relative humidity	10％～100％
  	Active power	≤3W
  	Apparent power	≤5W
  Port communication parameters	Communication mode	RS485 bus
  	Character format	1start bit，8 data bits，1 stop bit，1 even parity check bit
  	Port rate	default 2400，able to configure with infrared 1200,2400,4800,9600,19200bps
  	Maximum packet length	200 bytes
  Wireless communication parameters	Modulation system	LoRa modulation technology
  	Transmission Protocol	follows LoRaWAN wireless transmission protocol
  	Operating frequency band	CN470MHz/EU868MHz/AS923MHz
  	Transmitting power	≤17dBm
  	Receiving sensitivity	-146dBm ＠SF12，125KHz BW
  	Channel amount	48
  	Antenna interface	SMA female

• Performance Index

     Product application

Acquisition unit II(LoRaWAN wireless) is widely used in residence, industrial park, commercial complex, office building and farm for the meter data acquisition, status monitoring of device to realize intelligent and visual scenarios. Until now, the sales volume of our acquisition unit II (LoRaWAN wireless) has reached more than 50000 units, serving more than 50 million users of State Grid and Southern Power Grid.

Smart power data acquisition application

Commercial complex electric meter data acquisition and ultrasonic flow meter data acquisition

Air conditioner and electric meter data acquisition in airport

Electric meter data acquisition in residence community

Electromagnetic flowmeter, vortex flowmeter and environmental protection device data acquisition in industrial park

Switch cabinet data acquisition power distribution room