IRXON BT485 RS-485 Bluetooth Adapter

1. Introduction

Thank you for purchasing the BT485 serial Bluetooth adapter. This product replaces the traditional RS-485 bus within a range of approximately 100 meters, converting RS-485 connections into Bluetooth connections for wireless RS-485 communication. The BT485 can be configured as a Bluetooth master or slave via an Android app. It can be used in a pair (one slave, one master) or in a network (one slave, multiple masters). A BT485 slave can connect to up to 20 BT485 masters simultaneously, and through these masters, it can further connect to up to 255 RS-485 slave devices.

Connection Types:

• Traditional RS-485 Connection: A Master device connects to a Slave device via a wired RS-485 bus, with power supplied to both.
• Wireless RS-485 Connection: The BT485 adapter enables wireless RS-485 communication. A BT485 Master adapter connects wirelessly to a BT485 Slave adapter, replacing the physical RS-485 cable.

Wireless RS-485 Network: The BT485 supports a network configuration where one BT485 Master can wirelessly connect to multiple BT485 Slaves. A single BT485 Slave can connect to multiple BT485 Masters.

2. Product Information

2.1 Key Features

• Adapts to the RS-485 physical layer, supporting Modbus RTU and ASCII protocols.
• Offers simpler and more flexible networking compared to traditional wired RS-485 connections.
• The default Bluetooth role is slave, but it can be set as a Bluetooth master.
• A Bluetooth slave can connect to up to 20 Bluetooth masters concurrently.
• Bluetooth pairing encryption enhances wireless communication security.
• Provides fast and large data transfer capability with a maximum RS-485 baud rate of up to 921600 bps.
• Features 10dBm transmitting power, enabling communication distances up to 100 meters in open areas.
• Includes a built-in Watchdog for long-term reliable and stable operation.
• An Android app is supplied for adapter configuration, eliminating the need for AT commands.
• Supports a wide DC power range of 5V~36V, compatible with most RS-485 device power requirements.
• A serial TXD/RXD indicator displays data activity on the RS-485 serial port.

2.2 Specifications

• Bluetooth protocol: Version 5.1 BLE
• Selectable RS-485 baud rate: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600 bps
• TX power: 10dBm
• RX sensitivity: -98dBm
• Max wireless communication distance: 100 meters (line of sight)
• Default RS-485 communication settings: 115200, N, 8, 1
• Default Bluetooth name: BT485_xxxx (where xxxx are the last 4 digits of the MAC address)
• Default Bluetooth role: Slave
• Default Bluetooth pairing password (if encryption is enabled): 123456
• Android APP setting interface access password: irxon
• Typical working current: 5 mA
• Working Temperature Range: -20°C to 85°C
• Dimension and Weight: 41x41x17mm, 21g

Some specifications can be modified via the accompanying Android APP. Refer to section 4.3 for details.

2.3 Package List

• BT485 Bluetooth Adapter x1
• This User Guides (Electronic edition)

3. Hardware Description

Refer to the panel layout diagram on the first page for adapter details.

3.1 Restarting Button

Press the button to restart the adapter if communication issues arise.

3.2 LED Indicator

• Bluetooth Link Indicator (Blue): A constantly lit blue LED indicates Bluetooth is not connected. If connected to another BT485 adapter, the LED turns off. Note that a BT485 slave can connect to multiple masters; after connecting to the first master, the LED will turn off but will not prevent subsequent master connections.
• RS-485 TXD/RXD Indicator (Red): The red LED flashes to indicate when data is being sent or received through the RS-485 port.

3.3 Pinout of RS-485 Connecting Terminal

The RS-485 connecting terminal has the following pinout:

4. Instructions

The BT485 adapter is designed for use in pairs (one slave, one master) or in networks (one slave, multiple masters). Refer to the function diagram on page 2 for network configurations. Select the appropriate number of BT485 adapters based on your RS-485 network layout. Follow the steps below to connect and configure the adapter to transition wired RS-485 communication to wireless or partially wireless operation.

4.1 Connecting the Hardware

Connect the BT485 adapter to the RS-485 device as illustrated. Upon powering on, the blue LED will illuminate if the adapter is not yet connected to another Bluetooth device.

[Diagram Description: A diagram shows a BT485 Adapter connected to an RS-485 Device via the RS-485 terminals (A+, B-, GND, VCC) and a POWER connection.]

4.2 Installing BT485 Android APP

Download the app from the IRXON website: https://www.irxon.com/download/BT485_EN.zip. After extracting the zip file, install the APK file on your Android device. Ignore any system warnings during installation. Upon successful installation, a BT485 app icon will appear on your device's screen.

[App Icon Description: The BT485 Android application icon is displayed.]

When running the app for the first time, it will request location permission. Select "Allow only while using the app".

[Permission Dialog Description: An Android permission dialog is shown, asking for location access for the app, with options to 'Deny', 'Only this time', and 'Allow only while using the app'.]

The app automatically searches for Bluetooth devices. You can tap the round button at the bottom to stop the search. The app displays found BT485 adapters, such as 'BT485_C056' and 'BT485_FDD4'.

Tapping on a found BT485 adapter opens a new interface for testing Bluetooth communication. Tapping "Configuration" in the upper right corner accesses the configuration interface, which requires password verification upon first access. The default access password is 'irxon'.

[App Interface Description: The app interface shows a list of discovered Bluetooth devices. Tapping a device opens a communication test screen with options to view data format (Str/Hex) and send data. A 'Configuration' button is available.]

4.3 Configuration

In the app's configuration interface, set up BT485 adapters as follows:

• For the Bluetooth Slave: Connect the adapter to the RS-485 master device. Set its role to 'Slave' and match the RS-485 baud rate to that of the RS-485 master device. Record the 12-digit MAC address of this slave adapter for the next step.
• For the Bluetooth Master: Connect the adapter to the RS-485 slave device. Set its role to 'Master' and match the RS-485 baud rate to that of the RS-485 slave device. In the 'Binding Slave Address' field, enter the MAC address of the Bluetooth slave recorded previously.

[Configuration Screenshots Description: Two screenshots of the app's configuration interface are shown. The left shows settings for a 'Slave' role (e.g., BT485_FDD4) with MAC address, Bluetooth Name, RS-485 Baud Rate, and role selection. The right shows settings for a 'Master' role (e.g., BT485_C056) with similar fields and a 'Binding Slave Address' input.]

A wireless RS-485 network can have only one BT485 Bluetooth slave but can accommodate up to 20 Bluetooth masters. Add additional masters to the network by repeating the Bluetooth master configuration step.

4.4 Wireless RS-485 Communication

After configuration is complete and the adapter is restarted, the BT485 Bluetooth master will automatically search for and connect to its bound BT485 Bluetooth slave. The blue LED on the master adapter will turn off once the Bluetooth connection is established, indicating readiness for wireless RS-485 communication.

In the configuration examples, BT485_FDD4 is connected to a PC via USB to RS-485 cable, acting as the RS-485 master. BT485_C056 adapter is connected to a 4-Digit 7-Segment LED Display, acting as the RS-485 slave. Once the two BT485 adapters are connected via Bluetooth, it functions as an invisible RS-485 cable between the PC and the LED display.

To test this setup, open a serial communication program on the PC (e.g., SSCOM5.13) and send a Modbus-RTU instruction: 7F 06 00 00 22 B8. The LED display should then show '8888'. The instruction components are: '7F' is the RS-485 address, '06' is the function code (write single register), '00 00' is the register address, and '22 B8' is the hex value (decimal 8888) to be written.

[SSCOM Software Description: The SSCOM software interface displays serial communication logs, showing sent and received data, port settings, and communication parameters. An example Modbus-RTU instruction and its response are visible.]

4.5 Pairing Encryption

To enhance wireless communication security, it is recommended to enable pairing encryption. All BT485 masters and the slave must have pairing encryption enabled with the same password, configured via the BT485 app. The default pairing password is '123456'. If changed, ensure the new password is recorded to prevent loss.