---
title: "GWU-4 2G/4G Modbus RTU gateway, two digital inputs | GridBit"
description: "GWU-4 is a DIN-rail communication module. It reads the devices on an RS485 Modbus RTU bus, sends their data to the EIM center over 4G LTE Cat 1 or 2G, and."
url: "https://www.gridbit.tech/hardware/gwu-4"
language: "en"
translation: "https://www.gridbit.tech/bg/hardware/gwu-4"
---

# GWU-4

2G/4G gateway for Modbus RTU devices, two digital inputs

[Request a quote](https://www.gridbit.tech/contact?product=GWU-4)

- **Mobile network, 2G fallback**: 4G LTE Cat 1
- **Modbus RTU**: RS485
- **Digital inputs**: 2
- **Supply voltage**: 9 to 24 VDC

Overview

## Where it works

GWU-4 is a DIN-rail communication module. It reads the devices on an RS485 Modbus RTU bus, sends their data to the EIM center over 4G LTE Cat 1 or 2G, and writes parameters received from the EIM center into their Modbus registers. It has two digital inputs for tamper contacts and switches and runs on 9 to 24 VDC.

Mounting: 35 mm DIN rail (IEC 60715)

1. Full integration with the GridBit system for energy monitoring and management (EIM)
2. Reading data from, configuring and controlling the other devices on the Modbus bus remotely over 4G LTE
3. Monitoring the state of its two digital inputs, for example tamper contacts and switches

GWU-4 gateway, three-quarter view

Datasheet

## Technical data

### Power supply

- **Supply voltage**: 9 to 24 VDC
- **Consumption**: max. 150 mA

### Digital inputs

- **Number**: 2
- **Type**: IEC 61131-2 Type 1

### Modbus RTU

- **Interface**: RS485
- **Protocol**: Modbus RTU
- **Baud rate**: 9600, 19200, 38400, 57600 default 9600
- **Parity**: 8N1, 8E1, 8O1, 8N2 default 8N1

### Wireless communication

- **Mobile network**: 4G LTE Cat 1 (FDD/TDD), 2G (GSM/GPRS/EDGE)
- **Wi-Fi**: 2.4 GHz, IEEE 802.11 b/g/n, up to 150 Mbps optional
- **IoT application protocol**: MQTT
- **Message format**: JSON

### Environment

- **Operating temperature**: -20 to 60 °C
- **Storage temperature**: -20 to 80 °C
- **Relative humidity**: below 95 %, non-condensing

### Status LEDs

- POW On Input voltage present
- COM Blinking Connecting to the mobile operator
- COM On Connected to the EIM center
- DI1 On Digital input 1 closed
- DI2 On Digital input 2 closed
- MB On A device on the Modbus bus is missing or faulty

Installation

## Dimensions and connection

Dimensions in mm

Connection diagram

On a 35 mm DIN rail

Systems

## Used in

EIM

### [Electrical infrastructure monitoring](https://www.gridbit.tech/solutions/eim)

Sensors, analysers and a gateway turn a secondary substation into a monitored asset. The platform shows the transformer and the low-voltage board in real time, with alarms and reports for the grid operator.

Learn more

[Previous GWU-5 4G LTE gateway for Modbus devices, with Ethernet and MQTT](https://www.gridbit.tech/hardware/gwu-5)
[Next GWU-2 2G GSM/GPRS gateway for Modbus RTU devices](https://www.gridbit.tech/hardware/gwu-2)

### Transport, warranty and maintenance

- **Transport and storage**: Protect the module from shocks and avoid extreme conditions. Store it in the original packaging.
- **Warranty**: Two years from the date of manufacture against manufacturing defects. Modifications to the product after the publication date of its documentation release the manufacturer from liability. The manufacturer is not responsible for typographical or other errors in the documentation.
- **Maintenance**: Under normal conditions the module needs no maintenance. Light dirt comes off with a dry or slightly damp cloth; for heavier dirt use non-aggressive cleaning products. Always disconnect the power supply first, keep liquids out of the housing and reconnect the power only when the module is completely dry.

## Ask for a GWU-4 quote

Tell us the quantity and the project. We answer with a price and lead time.

[Request a quote](https://www.gridbit.tech/contact?product=GWU-4) [office@add-bg.com](mailto:office@add-bg.com)