The Johnson MA3-BK Bluetooth Module is designed to facilitate data collection, fault record saving, program upgrading, and engineering parameter backup for compatible units. This module serves as a communication bridge between the main unit and a mobile phone or USB flash drive, enabling various diagnostic and maintenance tasks.

Function Description:

The Bluetooth module allows for several key functionalities:

Bluetooth Communication: It connects to a mobile phone via Bluetooth, indicated by a blue LED1. This connection enables interaction with the LetsLink application for various operations.
Device Communication: The module communicates with the indoor unit (IDU) and outdoor unit (ODU) of the connected device, indicated by a green LED2. This communication is crucial for monitoring the device's operational status.
Data Sending: The module can send commands and data to the connected device, indicated by a red LED3. This includes sending firmware updates to the device or rewriting its serial number (SN).
Data Export: It supports exporting fault records and test run data, indicated by a red LED4. This data can be saved to a USB flash drive or exported to the LetsLink application for analysis.
USB Flash Drive Connection: The module features a USB port for connecting a USB flash drive, indicated by a red LED6. This connection is used for program upgrading and data export.
Program Upgrading: The module can update its own software or the software of the connected ODU using a FAT32 formatted USB flash drive containing a BIN file.
Fault Record: The module stores information and waveform data for the last 10 faults, along with IDU and ODU operating data from before these faults (32 sets of operating data, including data at the time of the fault, 30 seconds before, 1 minute before, and 2 to 30 minutes before the fault).
Test Run Report: During system test runs, the module verifies the operating state of the connected device and records the results and data of the latest test run.
Factory Settings Restore: Pressing and holding SW1 for 15 seconds restores factory settings, clearing Bluetooth connection information.

Important Technical Specifications:

Model: MA3-BK
Transmission Mode: Bluetooth
Dimensions: 237 x 86 x 35 mm
Type: Control
Rated Voltage: SELV DC12V
Rated Power: 2W
Kind of Load: Non
Frequency: -- (Not specified for operation, likely referring to power frequency if applicable, but Bluetooth frequency is 2.402~2.480 GHz)
Rated Impulse Voltage: 330V
Switch Type and Number of Poles: --
Construction: --
IP-Protection Degree: IPX5 after mounting (indicates protection against water jets from any direction)
Degree of Pollution: 2
Temperature: -30~55°C
Connecting Device: Depends on the end-product
Tracking Resistance: --
Glow Wire: 550°C
Bluetooth Transmit Frequency Range: 2.402~2.480 GHz
EIRP (Equivalent Isotropically Radiated Power): Not more than 20 dbm

Usage Features:

LED Indicators: Six LEDs (LED1-LED6) provide visual feedback on the module's status:
- LED1 (Blue): Bluetooth communication (slow blinking for waiting connection, remains on for connected).
- LED2 (Green): Device communication (slow blinking for communication failure, fast blinking for normal communication but unidentified model, remains on for normal communication with ODU).
- LED3 (Red): Data sending (slow blinking for receiving firmware, fast blinking for sending firmware or rewriting SN, remains on for pressing SW1 for 5s, off for not sending data).
- LED4 (Red): Data export (fast blinking for exporting fault record or test run data, off for not exporting data).
- LED5 (Red): Reserved.
- LED6 (Red): USB flash drive connection (remains on for normal connection, slow blinking for export/receive errors, off for no USB).
Buttons (SW1, SW2):
- SW1:
  - Press twice in succession (within 100-750ms) 5 seconds after power-on: Upgrades the USB flash drive (if connected).
  - Press and hold for 5 seconds: Resets factory settings (clears Bluetooth connection information).
  - Press and hold for 15 seconds: (Function not explicitly stated for 15s hold, but 5s hold is for factory reset).
- SW2:
  - Press twice in succession: Exports fault record and test run data to the USB flash drive.
  - Press and hold for 5 seconds: Stops upgrading.
LetsLink App Integration: The module is designed to work with the LetsLink application, allowing users to connect via Bluetooth, access HVAC Assistant, Smart Tools, and initiate connections.
QR Code Scanning: If the Bluetooth module cannot be found in the app, a QR code on the module can be scanned for connection.

Maintenance Features:

Firmware Upgrading: Users can update the module's firmware or the connected ODU's firmware using a USB flash drive. It's crucial to ensure only one BIN file is on the USB drive before starting the upgrade.
Fault Record Export: The ability to export fault records and test run data to a USB flash drive or the LetsLink app aids in diagnosing and troubleshooting issues.
Diagnosis Software: Fault records can be analyzed using diagnosis software for reference.

Installation Precautions:

Installation must be performed by qualified technicians designated by the local dealer or service agent. Self-installation is not permitted.
Do not strike, throw, or disassemble the Bluetooth module.
The module has a low-voltage circuit. Its wires must be connected according to the wiring guide and protected from direct exposure to high-voltage wires. Low-voltage wires should not be placed in the same conduit as high-voltage wires.
Do not install the module in corrosive, flammable, or explosive environments, or in areas with oil mist (e.g., kitchens).
Do not install the module when the unit is operating or powered on.
Ensure the silicon seal is properly reinstalled if it comes out during installation or opening to prevent water ingress.
Tighten the screws on the Bluetooth module after installation and checking to prevent water from entering.
High-voltage (power supply) and low-voltage (communication) wires must be separated.

Johnson MA3-BK - Page 71

Table of Contents