I. System Overview
Lightning disasters are listed among the ten most severe natural disasters identified by the United Nations International Decade for Natural Disaster Reduction, and lightning strikes cause countless casualties and property damage worldwide each year. Currently, the most effective method for preventing lightning disasters is to ensure that lightning protection grounding conductors are reliably grounded, thereby allowing lightning currents to safely dissipate into the earth. Practical experience from numerous lightning disaster incidents demonstrates that the quality of grounding resistance is critical to the lightning protection safety of all types of buildings and equipment. The challenge in maintaining grounding systems lies in their concealed nature; grounding conductors are susceptible to environmental factors that can cause corrosion, loosening, or even breakage, rendering them ineffective.

Both international and domestic industry standards require regular testing of ground resistance to identify potential hazards in grounding systems and prevent lightning-related accidents caused by system failure. However, manual on-site measurements suffer from numerous drawbacks, including long intervals between tests, outdated measurement methods, significant susceptibility to environmental factors, large measurement deviations, poor reliability, low efficiency, and high labor costs. The national standard “GB 17681-2024 Technical Specifications for Safety Monitoring of Major Hazard Sources of Hazardous Chemicals” explicitly stipulates that “for above-ground storage tanks containing flammable and explosive media in storage units located in areas with severe soil corrosion or high lightning activity, an online ground resistance monitoring system shall be installed to monitor the ground resistance value at the grounding point of each tank in real time; the ground resistance value shall not exceed 10 Ω.”

EM2800-MT IoT Online Ground Resistance Monitoring System employs advanced technology to continuously monitor potential hazards in grounding systems, It performs real-time online testing of parameters such as ground resistance, ground current, voltage to ground, lightning current, and number of lightning strikes. The monitoring system operates without affecting the normal functioning of the monitored grounding system. In the event of an anomaly in the monitoring circuit, an alarm is triggered, providing scientific and accurate data for grounding system maintenance. This effectively improves the quality of lightning protection grounding, helps prevent lightning disasters, and is widely applicable in industries such as petroleum, petrochemicals, power, telecommunications, mining, underground operations, railways, meteorology, and military sectors. It performs real-time, precise online testing of lightning protection grounding, protective grounding, and working grounding resistance for buildings, power facilities, electrical equipment, oil depots, metal storage tanks, and distribution boxes.

II. Introduction to the Monitoring System

1. System Components

EM2800-MT IoT Online Ground Resistance Monitoring System primarily consists of a detector, a low-power data acquisition unit, a monitoring system, host computer software, and backend system software. The detector performs real-time online testing of parameters such as ground resistance, ground current, voltage to ground, lightning current, and number of lightning strikes in the grounding system. It connects to the host computer network system or 4G network system via RS485, LoRa, or 4G communication, or through a data acquisition unit, to meet user needs in various scenarios.
The testers are available in various models and styles, including non-contact testers, ground stake testers, and explosion-proof testers. The host computer network system exchanges data with the server via a gateway or industrial control computer. The 4G network system exchanges data with the server via 4G communication. Users can configure test parameters and alarm thresholds in the system backend to enable remote online monitoring of ground resistance conditions.

                              (Architecture of the IoT Online Ground Resistance Monitoring System)

2. System Features

1) Comprehensive Monitoring Capabilities: The system can monitor parameters such as ground resistance, ground current, voltage to ground, lightning current, and number of lightning strikes in real time.

2) Multiple Probe Types: A variety of probes are available, including non-contact, explosion-proof, and ground stake types.

3) High-Performance Sensors: The sensors in the detectors are manufactured using high-flux magnetic materials and encapsulation technology, ensuring stable performance and strong resistance to interference.

4) Multiple Monitoring Systems: The detectors support RS485, LoRa, and 4G communication. Through low-power data acquisition devices, various network systems can be established to enable remote online monitoring, meeting the needs of diverse environments.

5) Low-Power Data Acquisition Module: Equipped with RS485, LoRa, and 4G communication capabilities for network deployment. The module features a built-in high-capacity lithium-ion battery or can be configured with a solar panel to address power supply challenges at remote sites.

6) Alarm Function: Alarm thresholds can be configured on the detector or via the system backend. When measured values exceed these thresholds, the system issues an alarm notification. The monitoring system operates without interfering with the normal functioning of the monitored grounding system.

7) System Backend: Users can monitor and record parameters such as ground resistance in real time, set alarm thresholds, and view alarm information through the IoT system backend. The backend includes features such as account management, information management, area management, and device management.

3. Measurement Range and Accuracy

4. Other Technical Specifications

5. Explosion-Proof Certification
The petrochemical industry is particularly vulnerable to lightning strikes. Equipment installed and used in flammable and explosive environments must be certified as explosion-proof. EM offers a range of detectors designed as flameproof or intrinsically safe explosion-proof products, all of which have obtained the relevant explosion-proof certifications and are suitable for use in hazardous explosive environments such as coal mines, oil depots, and gas stations.

III. Detector Models and Types

EM has developed detectors in a variety of configurations to meet the needs of different environments. Among these, the non-contact detectors feature a design where the grounding wire passes directly through a hole in the unit, making installation convenient. The ground-stake detectors require the prior installation of auxiliary grounding stakes.

1. Types of Non-Contact Detectors

2. Ground-mounted detector

IV. Structure and Installation of the Detector

All non-contact detectors are equipped with mounting hardware and can be installed either on a ground wire or mounted on a wall.

1. Structure and Installation of Closed-Loop Detectors

Closed-loop detectors (EM2800B, EM2800C, EM2840C) feature a closed-loop sensor design. During installation, the grounding down conductor must first be disconnected. After the sensor is installed through the hole, the grounding conductor should be reconnected. The detectors can be installed using either the grounding wire mounting or wall-mounted methods. For grounding wire mounting, use the included hardware to clamp the sensor onto the grounding down conductor. This method is primarily used in multi-point grounding systems that form a grounding loop, such as in machine rooms, substations, gas stations, oil depots, buildings, and production lines.

                                                          （ Installation Diagram for a Closed-Loop Tester）

2. Structure and Installation of the Clamp-On Tester

The sensors of the clamp-on tester (EM2800KB, EM2800KC) feature a clamp-on design, eliminating the need to disconnect the grounding down conductor during installation. Simply separate the front and rear halves of the sensor, clamp it onto the grounding down conductor, and then reassemble the sensor. This makes on-site installation much more convenient. The detector can be mounted either on the grounding conductor or on a wall. For grounding conductor mounting, use the hardware provided with the unit to clamp it onto the grounding down conductor. This method is primarily used in locations where disconnecting the grounding down conductor is impractical.

                                                                  （Installation Diagram for a Swing-Type Tester）

3. Structure and Installation of Split-Type Detectors

For split-type testers (EM2800S, EM2800KS), the controller and sensor must be installed separately. The controller can be mounted on a DIN rail or wall-mounted. The sensor can be installed using either the grounding wire method or wall-mounted. For the grounding wire method, use the hardware provided with the unit to clamp the sensor onto the grounding lead. This configuration is primarily used in scenarios where on-site observation of ground resistance values is required.

4. Structure and Installation of the Stainless Steel Tester

EM2700TB stainless steel tester is an explosion-proof device. Both the sensor and the control box are made of 304 stainless steel, offering a premium, aesthetic appearance, robust durability, impact resistance, a high protection rating, and the ability to withstand extreme temperatures for all-weather use. If you select a model with a viewing window, you can check the ground resistance value on-site. The tester features a monolithic design. During installation, the grounding lead must first be disconnected; after the sensor is inserted through the hole, the grounding lead should be reconnected. The tester can be mounted either on the grounding lead or wall-mounted. For grounding lead mounting, the sensor is clamped onto the grounding lead using the hardware provided with the unit. It is primarily used in flammable and explosive hazardous locations such as oil depots, storage tanks, and mines.

EM2700TB tester can be equipped with a built-in low-power module and a high-capacity lithium battery, providing a battery life of 3 to 5 years, thereby addressing the challenge of limited power supply at the site. It can also be equipped with a built-in 4G communication module to enable remote online monitoring.

5. Structure and Installation of Ground Stake Testers

Ground stake testers use the three-wire method to measure ground resistance and the four-wire method to measure soil resistivity. Installation requires the prior placement of grounding stakes, and mounting options include rail mounting and wall-mounted installation. These devices are primarily used for online monitoring of single-point grounding systems, such as those found in communication stations, equipment rooms, and lightning rods.

6. Earth Loop Tester
EM3350 tester outputs a test current of 5 A and uses the four-wire method to measure parameters such as ground resistance, continuity resistance, voltage to ground, soil resistivity, step voltage, and contact voltage. The tester transmits data packets to a host computer via RS485 communication and requires an external AC 220 V power supply. During installation, auxiliary grounding rods must be pre-installed as required; the tester can be mounted inside a cabinet. It is primarily used for online monitoring of large-scale grounding systems in substations, large buildings, and similar facilities.

V. Low-Power Data Acquisition Unit

The EM2600 low-power data acquisition unit, developed by ETCR, is a data acquisition module specifically designed to provide power and communication for online monitoring devices. The unit consists of a master unit, slave units, communication cables, RS485 communication, LoRa communication, and 4G communication. The master unit and slave units form a network via LoRa communication, with the master unit centrally receiving data from all slave units on-site. The master unit actively transmits data packets via RS485 or 4G communication to enable online monitoring of field devices. The master unit can be configured with a 4G communication module to upload data packets to a server. The slave units collect data from the monitoring devices via RS485 while simultaneously providing a 12V DC power supply to the devices, addressing the challenge of power supply in the field.

Users can establish both a host-based network monitoring system and a 4G network monitoring system using the monitoring devices and low-power data acquisition units.

EM2600 lithium-silver battery model features a built-in high-capacity lithium-silver battery, providing 3 to 5 years of battery life.

VI. Setting Up the Monitoring Network System

The EM2800-MT monitoring system primarily consists of a wired network system for the host computer and a 4G wireless network system. Users can configure various types of network monitoring systems based on their specific needs and on-site conditions. Test data is uploaded to the system’s backend via RS485 communication, the Internet, or 4G communication, enabling remote online monitoring.

1. Setting Up the Host Computer Network System (RS485)

A wired network monitoring system (RS485) is established using the RS485 communication module built into the monitor. The monitor transmits monitoring data to the host computer via RS485 communication. The monitor is powered by an external power source.

2. Setting Up the Host Computer Network System (RS485 + Low-Power Data Acquisition Unit)

Use the EM2600 low-power data acquisition unit to set up a wired host computer network system (RS485 + low-power data acquisition unit). The master unit collects data from various field sensors via LoRa communication and transmits it to the host computer via RS485 communication, while the slave units collect sensor data and simultaneously provide power to the sensors.

 3. Setting Up a 4G Wireless Network System (4G)

A 4G network monitoring system is established using the 4G communication module built into the monitor. The monitor transmits monitoring data to the server via 4G communication and is powered either by an external power source or a built-in high-capacity lithium battery.

4. Setting Up a 4G Wireless Network System (4G+ Low-Power Data Logger)

A 4G network monitoring system is established using the 4G version of the ETCR2600 low-power data logger. The master unit collects data from various field sensors via LoRa communication and transmits it to the server via 4G. The slave units collect sensor data while simultaneously providing power to the sensors.

VII. Monitoring System Backend

The EM2800-MT IoT Online Ground Resistance Monitoring System displays test parameters such as ground resistance, ground current, voltage to ground, soil resistivity, step voltage, contact voltage, lightning current, and number of lightning strikes based on data reported by the testers, enabling real-time remote data monitoring. It features functions such as historical data querying, alarm threshold configuration, data alarm notifications, and user information setup.

(IoT Ground Resistance Online Monitoring System - Login)

1. Data Overview
The Data Overview page displays the system’s overall operational status. The page supports filtering by region and provides summary information on key system metrics, including: a trend chart showing daily changes in the number of alerts; the number of product types; the total number of devices; the number of devices online; and the number of devices offline. This page provides an overview of the system’s device connectivity and operational status.

(IoT Online Ground Resistance Monitoring System – Data Overview)

2. Account Management
The Account Management feature is used to maintain and manage system user information and to control user permissions. Key features include: searching for users by username; viewing user information; adding sub-users (regular users do not have permission to add users); and deleting users. This feature is used to centrally manage system users.

(IoT Online Ground Resistance Monitoring System – Account Management)

3. Region Management
The Region Management feature supports adding, modifying, deleting, and querying region information. After adding a region, you must bind devices on the region details page; only after binding is complete can you view the corresponding device data in the system. Key features include: adding region information; modifying region information; deleting region information; querying region information; binding devices on the region details page; and viewing corresponding device data after device binding is complete. This feature is used for centralized management of the regions to which devices belong, facilitating the viewing of device data by region.

(IoT Online Ground Resistance Monitoring System – Regional Management)

4. Device Management
The Device Management feature is used to maintain and view information about devices connected to the system. Through this feature, you can manage basic device information and view the current status of devices. On the device details page, you can view device monitoring parameters and historical data. Key features include: adding new device information; modifying device information; deleting device information; querying device information; viewing the current status of a device; viewing device monitoring parameters on the device details page; and viewing historical data on the device details page. This feature is used to centrally manage device information within the system and view device-related data.

(IoT Online Ground Resistance Monitoring System – Equipment Management)

5. Alarm Information
The Alarm Information feature is used to view alarm records generated when device monitoring data meets alarm conditions. Alarm information includes the alarm time, device ID, device manager, alarm type, and handling status (resolved/unresolved). Key features include: viewing alarm records; querying alarm information by device; querying alarm information by time range; and viewing alarm handling status (resolved/unresolved). This feature allows users to view alarm records generated by device monitoring data, helping them understand device anomalies.

(IoT Online Ground Resistance Monitoring System – Alarm Notifications)