# 8-ch Ethernet Relay Module (B)

**Type:** Product page · **SKU:** WS-27876 · **Brand:** [Waveshare](https://core-electronics.com.au/brands/waveshare-in-australia)
**Page:** https://core-electronics.com.au/8-ch-ethernet-relay-module-modbus-poe-industrial.html ([markdown](https://core-electronics.com.au/8-ch-ethernet-relay-module-modbus-poe-industrial.html.md))

8-ch Ethernet Relay Module (B) With Digital Input, Modbus RTU/Modbus TCP Protocol, PoE Port Communication, With Various Isolation And Protection Circuits,...

## Pricing

- **Price:** $76.35 (inc GST) — $69.41 AUD, exc GST
- **Quantity discounts:** 6+ $66.64 (exc GST) · 12+ $64.55 (exc GST)

## Availability & dispatch

- In stock, ships same business day if ordered before 2PM (Australia/Sydney).
- We can dispatch 8 today, and up to 300 more in 12–19 days.

## Description

The 8-channel Ethernet Relay Module (B) is an industrial-grade relay module controlled via Ethernet with 8 digital inputs. It supports Modbus RTU/Modbus TCP protocols, features PoE power supply, and comes in an ABS rail-mount case for easy installation and industrial use.

### Features

This product offers robust functionality for industrial control equipment, providing fast communication, stability, and reliability. Key features include:

- Flash-on, flash-off function for timed relay activation.
- Supports DC 7~36V wide-range power input and PoE power supply.
- MQTT protocol relay control with Alibaba Cloud MQTT application demo.
- Optocoupler isolation to prevent high-voltage circuit interference.
- Dedicated relay driver chip with built-in flyback diode protection.
- Passive and active digital input support with bi-directional optocoupler isolation and debouncing algorithm.
- Reverse-proof circuit for accidental connection protection.
- High-quality relay with contact rating: =10A 250VAC/30VDC.
- Rail-mounted ABS plastic enclosure for easy installation and safety.
- LED and network indicators for monitoring MCU status and signal transmission.
 
### Primary Function

The module supports reading digital inputs via Modbus RTU protocol commands sent through Ethernet to control relay outputs.

 ![8-ch Ethernet Relay Module (B), primary function](https://core-electronics.com.au/attachments/localcontent/Modbus-POE-ETH-Relay-B-details-3_14225e46010.jpg)### Communication Modes

The module supports various communication modes:

- TCP Server
- TCP Client
- UDP Mode
- UDP Multicast
- HTTP
- MQTT
 
It is compatible with Modbus RTU and Modbus TCP protocols.

 ![8-ch Ethernet Relay Module (B), Modbus protocol support](https://core-electronics.com.au/attachments/localcontent/Modbus-POE-ETH-Relay-B-details-4_6783504ac99.jpg)### Configuration Methods

Supports configuration through software or a web browser, with dynamic IP assignment via DHCP and domain name connection through DNS protocol.

 ![8-ch Ethernet Relay Module (B), multi-configuration methods](https://core-electronics.com.au/attachments/localcontent/Modbus-POE-ETH-Relay-B-details-7_188953acad8.jpg)### Power Supply Options

The module offers multiple power supply options:

- DC power port with plug support.
- Screw terminal for DC 7~36V input.
- PoE port compliant with IEEE 802.3af standards.
 
\*External power supply adapter is not included. A [12V power supply](https://core-electronics.com.au/ord-psu-12v2a-5.5-2.1.htm) is recommended if needed.

 ![8-ch Ethernet Relay Module (B), power supply options](https://core-electronics.com.au/attachments/localcontent/Modbus-POE-ETH-Relay-B-details-9_11081fb12e5.jpg)### Digital Input

Supports passive (dry contact) and active (wet contact) digital inputs with bi-directional optocoupler isolation.

 ![8-ch Ethernet Relay Module (B), digital input demo](https://core-electronics.com.au/attachments/localcontent/Modbus-POE-ETH-Relay-B-details-11_17649fa73fc.jpg)### Interfaces & Indicators

The module includes multiple LED indicators for easy monitoring:

 | RUN | Blinks when the Ethernet port is operating normally. |
|---|---|
| STA | Blinks when the MCU is functioning correctly. |
| TXD | Lights up during data transmission. |
| RXD | Lights up during data reception. |
| Ethernet Port Green Indicator | Indicates Ethernet connectivity status. |

 ![8-ch Ethernet Relay Module (B), interface and indicator details](https://core-electronics.com.au/attachments/localcontent/Modbus-POE-ETH-Relay-B-details-13_26614801376.jpg)### Dimensions

### ![](https://core-electronics.com.au/media/wysiwyg/Modbus-POE-ETH-Relay-B-details-size.jpg)

### Resources

- [Wiki for 8-ch Ethernet Relay Module (B)](https://www.waveshare.com/wiki/Modbus_POE_ETH_Relay_(B))

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/W/S/WS-27876-1.jpg)