BL191 OPC UA edge I/O module's application in intelligent building BMS integration. Targeting scattered equipment, protocol incompatibility, and inefficient maintenance, it pairs BL191 with Y-series modules to unify data collection of sensors/HVAC/lighting, enable remote control, and seamlessly connect to BMS—simplifying architecture, cutting costs, and ensuring stable 7×24 operation.
Case Details
In a high-end commercial office building, the existing building management system (BMS) faced a critical pain point: scattered control of lighting, air conditioning, and security equipment across floors, incompatible protocols between terminal sensors/actuators and the BMS, and inefficient on-site maintenance for 24/7 operations. The property management team needed a cost-effective, stable solution to unify data collection, enable remote control, and seamlessly link OT-layer devices (sensors, switches) with the IT-layer BMS. The
BL191 industrial-grade OPC UA edge I/O module was selected as the core to build a centralized integration system—leveraging its native OPC UA support, flexible expansion, and remote management capabilities to solve these challenges.
- Core Device: BL191 OPC UA edge I/O module (1 built-in RS485 interface, 2 Ethernet ports, 2 I/O expansion slots, Linux system with 300MHz CPU)
- Expansion Modules (Scenario-Specific Selection):
- Y33 (4-channel AI module): Collects 0~10V analog signals from temperature/humidity sensors in office areas
- Y01 (8-channel DI/DO mixed module, NPN type): 4 DI channels for lighting switch status detection; 4 DO channels for lighting on/off control
- Y24 (4-channel relay DO module): Controls high-power HVAC fan speed regulators and air conditioning compressors
- Terminal Devices (Realistic Building Deployment):
- 4 floor temperature/humidity sensors (output 0~10V analog signals)
- 8 lighting zone switches (dry contact signals for status feedback)
- 4 HVAC fan speed regulators (relay-controlled, 220VAC load)
- 2 air conditioning compressor emergency stop switches (NPN-type digital input)
- Upper-Layer System: Building BMS (supports OPC UA client protocol, deployed on the property management server)
- Auxiliary Equipment: DIN35 rail mounts (for BL191 and expansion modules), 24VDC redundant power supply, STP Cat 5 Ethernet cables, RS485 terminal blocks
- Power Supply Deployment: Connect the 24VDC redundant power supply to BL191’s power terminal, with reverse connection protection enabled. The power supply is installed in the floor electrical control cabinet, with separate wiring to avoid interference with signal lines.
- AI Module (Y33) Connection:
- Mount 1 temperature/humidity sensor in each of the 4 office zones (1st~4th floors). Connect the sensor’s 0~10V output terminals to Y33’s AI1~AI4 channels: sensor positive (+) to AI+ terminal, negative (-) to AI- terminal.
- Ensure wiring uses shielded cables (AWG18) to reduce electromagnetic interference from building power lines, with cable length ≤20m per channel.
- DI/DO Module (Y01) Connection:
- Connect the dry contact terminals of 8 lighting zone switches to Y01’s DI1~DI8 channels: each switch’s normally open contact to the DI channel terminal, and the COM terminal to the switch’s common ground.
- Wire the 4 DO channels (DO1~DO4) of Y01 to the lighting zone relays: DO channel output terminal to the relay coil positive, and the relay coil negative to the 24VDC power ground.
- Relay Module (Y24) Connection:
- Connect Y24 to BL191’s second expansion slot. Wire Y24’s AO1~AO4 relay output terminals to the HVAC fan speed regulators: AO+ to the regulator’s control terminal, AO- to the 220VAC neutral line.
- The air conditioning compressor’s emergency stop switch (NPN-type) is connected to Y01’s DI7~DI8 channels: switch signal terminal to DI channel, common terminal to 0VDC.
- BL191 Core Connections:
- Insert Y33 and Y01 into BL191’s two expansion slots, fasten with screws to ensure pin contact. Y24 is cascaded via BL191’s Ethernet Port 2 (reserved for future floor expansion).
- Connect BL191’s Ethernet Port 1 to the building’s industrial switch via STP Cat 5 cable, and the switch is connected to the BMS server (network segment: 192.168.2.0/24, BL191 static IP: 192.168.2.150).
- Reserve BL191’s built-in RS485 interface for future connection of intelligent energy meters (wiring terminal A/B marked for easy expansion).
- Network & Protocol Setup:
- Connect a laptop to the building’s LAN, enter BL191’s static IP (192.168.2.150) in the browser to access the built-in Web server (default login: admin/123456).
- Enable the OPC UA server function, set the data update interval to 300ms (matching Y33’s sampling cycle), and configure the OPC UA node names to align with BMS tags (e.g., "Zone1_Temp", "Lighting_Zone2_Status").
- Set Y33’s AI channels to 0~10V single-ended input, enable 16-bit resolution, and calibrate accuracy to ±0.1% FSR via the Web interface.
- I/O Channel Configuration:
- Configure Y01’s DI1~DI8 as dry contact input: "closed" = lighting on, "open" = lighting off. Set DO1~DO4 as NPN output (0VDC active) to trigger lighting relays.
- Set Y24’s relay output mode to "normally open", with switch voltage rated at 220VAC (matching HVAC regulator requirements).
- Security & Access Control:
- Upload the BMS server’s X.509 certificate to BL191 via the Web server, enable AES-256 encryption for data transmission (complying with IEC 62443), and create two user roles: "Property Admin" (full configuration rights) and "Operator" (monitoring-only rights).
- Data Collection & Standardization:
- Y33 converts the 0~10V temperature/humidity signals from each floor into digital data (e.g., 0V = 0℃, 10V = 50℃) and transmits it to BL191 via the internal bus.
- Y01 collects the dry contact status of lighting switches: when a zone switch is pressed, the DI channel sends a signal to BL191, indicating the current lighting status.
- BL191’s CPU unifies these heterogeneous data (analog signals, digital status) into OPC UA standard data models, eliminating protocol incompatibility with the BMS.
- Secure Data Upload to BMS:
- Encrypted data (AES-256) is transmitted from BL191’s Ethernet Port 1 to the BMS server. The BMS dashboard displays real-time temperature/humidity and lighting status for each floor, with abnormal thresholds set (e.g., temperature > 26℃ triggers an HVAC adjustment alert).
- Remote Control Workflow:
- When the BMS detects Zone 3 temperature exceeds 26℃, it sends an OPC UA control command to BL191.
- BL191 activates Y24’s AO2 relay output, triggering the HVAC fan to switch from low to medium speed.
- When the temperature drops below 24℃, the BMS sends a stop command, and BL191 deactivates the relay to restore low-speed operation.
- For lighting control: The property operator can remotely turn off unused zone lighting via the BMS, with Y01’s DO channel outputting 0VDC to activate the relay and cut off power.
- BLRAT Remote Access: The property’s technical team installs the BLRAT tool on their off-site PC, enters BL191’s unique token (generated via the Web server), and establishes a remote connection through the BLIoT cloud—no need for on-site visits during off-hours.
- Real-Time Monitoring: Remotely view Y33/Y01/Y24 channel data via the Web server: check if a temperature sensor is malfunctioning (e.g., static 0V signal) or if a lighting relay fails to respond (DO channel output abnormal).
- Firmware & Configuration Management: Periodically back up BL191’s configuration parameters (via the Web server’s "Export" function) to avoid data loss. When a new firmware version is released, upload the .bin file via BLRAT for remote upgrade (supports breakpoint resumption to prevent upgrade failures).
- Seamless BMS Integration: BL191’s native OPC UA protocol eliminated the need for intermediate protocol converters, reducing the building’s control system complexity by 40% and enabling 100% data compatibility between terminal devices and the BMS.
- Operational Efficiency: Remote control of lighting and HVAC reduced on-site maintenance workload by 70%—the property team no longer needs to manually adjust equipment across 4 floors, cutting labor costs by 35%.
- Stable Operation: BL191’s industrial-grade design (-40~85℃ wide temperature, IP30 protection, EMC Level 3 certification) ensured 7×24 stable operation in the building’s electrical control cabinets, with zero downtime over 6 months.
- Scalability: The reserved expansion slot and RS485 interface allowed the property to later add 8 intelligent energy meters, extending the system to energy consumption monitoring without replacing the core module.
