Grounding Resistance Monitor (Indoor)
Precision Three-Wire Method + Local LCD Display, 35mm DIN Rail Indoor Grounding Grid Monitor
Suitable for online monitoring of lightning protection grounding grids. Uses precision three-wire method to measure grounding resistance and ground voltage in real time. Data can be uploaded to the cloud platform via RS485 (Modbus) and integrated into lightning protection systems. Supports local LCD display and button operation, easy installation, suitable for indoor environments such as distribution rooms.
Product Overview
The Indoor Grounding Resistance Monitor is an indoor screw/DIN-rail mounted grounding resistance monitoring device suitable for online monitoring of lightning protection grounding grids. It uses the precision 3-wire method to measure grounding resistance and ground voltage in real-time, and data can be uploaded to the cloud platform via RS485 (Modbus), integrating with the lightning protection system.
The device supports local LCD display and button operation, with easy installation suitable for distribution rooms and other indoor environments. It automatically performs a measurement every minute, reflecting grounding grid health status in real-time without manual intervention.
Core Capabilities
- Precision three-wire measurement, resistance 0.01Ω~2000Ω, voltage 0.1V~600V.
- Every minAuto Measurementoneorder,real-timeDynamicreflects grounding grid healthstatus.
- Standard Modbus, supports bus networking, remote cloud monitoring via gateway.
- LCD + multi-button interaction, supports line resistance clearing, ID setting, test start/stop and other field operations.
Product Features
Precision 3-Wire Measurement
Resistance 0.01Ω~2000Ω, voltage 0.1V~600V, captures minor changes clearly, grounding resistance accuracy ±2%rdg±3dgt.
Wide Range, High Resolution
Standard Modbus, supports bus networking, remote cloud monitoring via gateway, grounding grid health at a glance.
RS485 Remote Transmission
Every minautomaticexecuteoneorderMeasurement,real-timeDynamicreflects grounding grid healthstatus,noneedmanual intervention,dataremotetransmissiontoCloud Platform.
Smart Self-Test
Every minautomaticexecuteoneorderMeasurement,real-timeDynamicreflects grounding grid healthstatus,noneedmanual intervention,ensuringdatacontinuousUpdate.
Convenient Local Control
LCD with multi-button interaction, supports line resistance clearing, ID setting, test start/stop and other field operations, configuration without external devices.
DIN Rail Quick Mount
35mm standard DIN rail clip-on mounting, compact size (62×117×88mm), suitable for dense deployment in indoor distribution cabinets.
Selection Guide
Model Naming Rules
| Model | Mounting Location | Measurement Method | Acquisition Points | Dimensions (mm) | Mounting | Communication | ZIGBEE | Ethernet | 4G |
|---|---|---|---|---|---|---|---|---|---|
| FR-12021-R | Indoor | 3-point method | Resistance + Ground voltage | 62*117*88 | IndoorDIN Rail | RS485 | Yes | --- | --- |
| FR-12021-E | Indoor | 3-point method | Resistance + Ground voltage | 62*117*88 | IndoorDIN Rail | Ethernet | --- | Yes | --- |
| FR-12021-Z | Indoor | 3-point method | Resistance + Ground voltage | 62*117*88 | IndoorDIN Rail | Zigbee | Yes | --- | --- |
| FR-12031-R | Indoor | 3-point method | Resistance + Ground voltage | 62*117*88 | Indoorscrew | RS485 | Yes | --- | --- |
Technical Parameters
Basic Parameters
| Operating Voltage | 12V±1VDC,150mA Max |
| Power Consumption | 2W |
| Operating Temperature | -10℃~40℃ |
| Operating Humidity | <95% |
| Weight | 230g |
| Dimensions | 62*117*88mm |
| Display Size | 34.5mm×23mm; display area: 29.42mm×14.7mm |
| Enclosure Material | flame-retardant material(Indoor) |
| Protection Rating | IP20(Indoor) |
| Mounting | 35mm DIN Rail(Indoor) |
| Communication | RS485 |
| Protocol | Modbus |
Monitoring Functions
| Grounding Resistance | 0.01Ω~2000Ω, 0.01Ω |
| Measurement Method | Precision 3-Wire Measurement |
| Measurement Time | 1min/orders |
| Grounding Resistance Accuracy | ±2%rdg±3dgt |
| Ground Voltage | 0.1V~600V, 0.1V |
| Voltage Accuracy | ±2%rdg±5dgt |
| Acquisition Points | Resistance + Ground voltage |
| Acquisition Method | 3-point method |
Installation Instructions
Installation Example
Interface Diagram
Interface Definition
| No. | Definition |
|---|---|
| 1 | Power positive (VCC) |
| 2 | Power ground (GND) |
| 3 | RS485 A terminal (T/A) |
| 4 | Communication ground (GND) |
| 5 | RS485 B terminal (R/B) |
| 6 | C terminal (current electrode) |
| 7 | Reserved terminal |
| 8 | P terminal (voltage electrode) |
| 9 | E terminal (grounding electrode) |
| 10 | LCD screen |
| 11 | Down button |
| 12 | Confirm & Test button |
| 13 | Down button |
| 14 | Mounting hole |
| 15 | Clip |
| 16 | DIN rail slot (35mm) |
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