In the current era of thriving Industrial Internet of Things (IIoT), remote meter reading systems, as an integral part of intelligent management, are gradually transforming traditional meter reading methods.Cellular Modem, serving as a crucial bridge connecting field devices and remote servers, plays a vital role in remote meter reading systems. This article, drawing on extensive industry experience, will provide a detailed introduction to the application of Cellular Modem s in remote meter reading systems from the perspective of configuration and usage methods.
Remote meter reading systems primarily consist of three major components: meter terminals, wireless transmission terminal devices (i.e., Cellular Modems), and data centers. Meter terminals are responsible for recording user electricity consumption data and transmitting it to Cellular Modems via RS232/RS485 interfaces. Cellular Modems, in turn, establish connections with operator networks to transmit electricity data to data centers at meter reading centers via wireless cellular networks (such as 2G/3G/4G/5G). Data centers process, analyze, and store the received data to achieve remote meter reading functionality.
The emergence of Cellular Modem s has resolved issues of high costs and poor real-time performance associated with traditional manual meter reading. With advantages such as good mobility, extensive coverage, and low communication costs, Cellular Modem s enable efficient and real-time remote reading of meter data, enhancing the management planning of power units for meter reading operations and addressing the challenges of managing dispersed deployment points.
SIM Card Installation: First, obtain two GPRS SIM cards from a local mobile service provider for data usage. Install the SIM cards into the Cellular Modem's card slots, similar to how they are installed in mobile phones. Ensure no power is applied during installation to avoid damaging the SIM cards or Cellular Modems.
● Device Connection
Connect the CELLULAR MODEM to the meter that requires meter reading, typically using RS232 or RS485 interfaces. If the meter terminal has an RS485 interface, the Cellular Modem should also use an RS485 interface for connection to achieve more stable and longer-distance data transmission. After connection, power on the device and connect the computer that needs to collect data to the Cellular Modem's serial port at one end.
Antenna Installation: Align and tighten the antenna connector with the antenna connector at the top of the Cellular Modems module to ensure a secure installation, guaranteeing that the Cellular Modem can receive and transmit signals normally.
Serial Port Parameter Settings: Use the Cellular Modem's management software for simple configuration, primarily setting the communication speed of the serial port. This parameter must be configured according to the actual baud rate, parity bit, data bit, stop bit, and flow control parameter values of the serial port of the lower-level machine (i.e., the device connected to theCellular Modems, such as a meter) connected to theCellular Modem. For example, if the baud rate of the lower-level machine's serial port is 1200, set the CELLULAR MODEM 's serial port baud rate option to 1200 as well, with other configuration items following suit. The baud rate should be set according to actual requirements, with a maximum of 115200.
● Data Center Parameter Settings
Before applying the Cellular Modems , configure it using the parameter configuration software provided with the CD to set the data center's IP, port, and other parameters. After configuration, connect the CELLULAR MODEM 's serial port to the collector's serial port. Upon powering on the Cellular Modems , it will connect to the pre-configured center IP and port.
Cellular Modems typically have two operating modes:
Always-On Mode:Suitable for scenarios with high meter reading frequencies. The Cellular Modems automatically connects to the mobile network and the meter reading data service center upon power-on and maintains the link between the meter and the meter reading data service center. In this mode, the data center can perform remote meter readings at any time, with strong real-time performance. For example, for large industrial users with significant fluctuations in electricity consumption that require frequent meter readings, the always-on mode can be adopted.
Suitable for scenarios with low meter reading frequencies, saving transmission costs. When the meter has data to upload or the meter reading data service center requests a meter reading via SMS, the CELLULAR MODEM begins connecting to the mobile network and the meter reading data service center to complete data transmission between the two. After transmission, it automatically returns to standby mode. For example, for residential users with relatively stable electricity consumption and low meter reading frequencies, the triggered online mode can reduce operating costs.
● Data Collection and TransmissionData Collection:
The Cellular Modems collects data from field devices (such as meters) via standard interfaces (such as RS232, RS485). In remote meter reading systems, the Cellular Modems reads electricity data from meter terminals, including current electricity consumption, last month's electricity consumption, total active and reactive power in four quadrants, and electricity consumption at peak, off-peak, flat, and valley rates.
Data Transmission:
The Cellular Modems transmits the collected data to cloud servers or data centers via wireless networks. During transmission, the Cellular Modems ensures the accuracy and integrity of the data. To enhance the stability and security of data transmission, the Cellular Modems supports encrypted transmission via protocols such as VPN and SSL.
Remote Monitoring:
Through Cellular Modems, remote monitoring of devices can be achieved. For example, the operating status of meters, such as voltage, current, and power factor parameters, can be monitored in real-time. If abnormal conditions, such as excessively high or low voltage or excessive current, are detected in the meter, timely measures can be taken to address them.
Remote Configuration and Firmware Upgrades:
Cellular Modem s support remote configuration and firmware upgrades. Through dedicated configuration software, parameters such as network parameters, serial port parameters, and VPN parameters can be set for Cellular Modem s via serial ports, networks, and other means. Firmware upgrades can be performed via Over-The-Air (OTA) upgrades, Firmware Over-The-Air (FOTA) upgrades, or local upgrades. This allows for timely repair of device vulnerabilities and errors, addition of new features, meeting evolving application requirements, and improving device stability and reliability.
Practical Application Cases of Cellular Modem s in Remote Meter Reading Systems
Meter Configuration:
Adopt three-phase active and reactive power multifunction meters and three-phase active multi-rate meters. These meters have RS485 communication interfaces and comply with the Ministry of Electric Power's DL/T645 communication protocol. The three-phase active and reactive power multifunction meter has an active accuracy of 0.5 and a reactive accuracy of 2, enabling the measurement of electrical energy (active and reactive) and parameters such as power factor, voltage, current, and frequency. The three-phase active multi-rate meter has an active accuracy of 1 and also supports the measurement of these parameters.
Collector Functions:
The collector has an RS485 interface for communication with terminals, three switch quantity input ports for alarm monitoring, and three analog quantity output ports for remote control. It supports departmental standard communication protocols, has power-outage data protection functions, and can still read meters after a power outage. Additionally, the collector has control output functions for remote control of circuit breakers or other functions and is equipped with a backup power supply.
System Functions:
The system can set meter parameters, read various measurement and management data; achieve statistics, queries, backups, reports, and chart generation of meter reading data; perform plant station management; support automatic meter reading, timed reporting, real-time queries, and other functions; have functions such as power-outage data preservation, comprehensive processing of instantaneous data, system data backup, archiving, and external data output; and provide multiple analog and switch quantity inputs to realize various alarm functions, such as open-box alarms, power-outage alarms, and reverse-phase alarms. It also has remote power control functions and collects rich parameters, including current, last month's, total active and reactive power in four quadrants, and electricity consumption at peak, off-peak, flat, and valley rates.
The design of the water supply remote meter reading system is basically the same as that of the power remote meter reading system and is also a typical application scheme for Cellular Modems
. The system consists of three major components: water meter terminals, wireless transmission terminals (such as Ruigu DT7010G), and data centers. Water meter terminals connect to
Cellular Modems
via RS232/RS485 interfaces for data transmission.Cellular Modems establish connections with operator networks and transmit data to meter reading centers via wireless GPRS/CDMA1X networks to achieve remote meter reading systems. This system can automatically complete remote data collection, recording, real-time monitoring, statistical analysis, printing, and water supply/shutdown control management of water user water meter networks.
Serial Port Parameter Consistency:
Serial port parameters must be configured to match the baud rate, parity bit, data bit, stop bit, and flow control of the lower-level machine device; otherwise, communication with the lower-level machine device will be impossible.
Signal Quality: When installing and using Cellular Modems, pay attention to signal quality. Judge signal quality by checking network login logs or based on the status of lights. If the signal is weak, adjust the antenna's position to ensure the CELLULAR MODEM can receive and transmit signals normally.
Data Traffic Costs:
Using Cellular Modems requires paying a monthly data traffic fee to the telecommunications operator. Therefore, when selecting an operating mode, choose reasonably based on actual requirements to reduce operating costs.
Safety Precautions:
Cellular Modems are usually installed in complex industrial environments, so safety precautions should be taken. For example, prevent physical damage and electromagnetic interference to the Cellular Modems . Ensure a stable power supply for the Cellular Modems to avoid equipment failures due to power issues.
The configuration and usage of Cellular Modems in remote meter reading systems require comprehensive consideration of hardware, software, operating modes, and other aspects. Through reasonable configuration and correct usage methods, the advantages of Cellular Modem s can be fully leveraged to achieve efficient and stable operation of remote meter reading systems. With the continuous development of IoT technology, the application scenarios of Cellular Modem s will become increasingly widespread, providing strong support for the digital transformation and intelligent development of the industrial sector. It is hoped that this article's introduction will be helpful in your practical work.
