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Overview
In a fixed gas detection system, the sensors installed throughout a facility are only half of the equation. The other half is what happens with the information those sensors generate. Individual field detectors monitor local atmospheric conditions and trigger local alarms — but without a central controller receiving their signals, consolidating their status, and managing the alarm and control outputs that follow, you have a system of isolated instruments rather than a coordinated safety response. For facilities with multiple gas monitoring points, the controller is where the detection data becomes actionable.
The BH-KZ102 Gas Controller is a compact, wall-mounted gas detection control panel designed for facilities that need centralised multi-point gas monitoring management without the physical footprint or power overhead of a larger panel. With a 7-inch high-definition touch screen, RS485 MODBUS digital communication, four sets of relay contact outputs, and a two-level alarm system, the BH-KZ102 consolidates field sensor signals into a single operator interface and connects that interface to the broader site monitoring and control infrastructure.
Where the BH-KZ102 earns its place over simpler alarm-relay panels in its category is in the combination of its MODBUS RS485 digital communication and its touch screen operator interface in a compact 37 × 24 × 10cm format at under 75W system power. For smaller facilities, light commercial buildings, and installations where panel space and power budgets are constraints, the BH-KZ102 delivers the core functionality of a full-size gas controller — MODBUS integration, relay control outputs, two-level alarming — in a form factor that fits where larger panels cannot.
Key Features
7-Inch High-Definition Touch Screen with Status Indicator Light
The BH-KZ102’s 7-inch touch screen provides a clear, navigable operator interface for multi-point gas detection management. Connected detection zone status, real-time alarm states, and system operating conditions are displayed on the screen and accessible through touch navigation without requiring separate configuration terminals or laptop connections. A dedicated status indicator light provides at-a-glance system health confirmation — normal operation, active alarm, or fault condition — visible without engaging with the screen display. For facilities managers and control room operators monitoring multiple systems, the indicator light provides an immediate visual cue that reduces the time needed to assess gas detection system status during routine monitoring rounds.
RS485 MODBUS Digital Communication
The BH-KZ102 communicates via one-way RS485 digital signal using the MODBUS protocol — the industry standard communication protocol for industrial automation, SCADA systems, building management systems, and safety PLCs. MODBUS RS485 support means gas concentration data, alarm events, and system status from the BH-KZ102 can be read automatically by any MODBUS-compatible site infrastructure system without custom protocol conversion or proprietary software. For facilities where gas detection data needs to feed into a central building management or safety monitoring platform, MODBUS RS485 is the communication standard that makes that integration straightforward.
Four Sets of Relay Contact Outputs
The BH-KZ102 provides four independent relay contact output sets — the same relay output capacity as the larger BH-KZ103, in a smaller and lower-power package. Four relay outputs allow independent automated responses to be assigned at different alarm conditions: one output triggering a local audible alarm, a second activating zone ventilation, a third operating a gas supply isolation valve, and a fourth signalling to a fire alarm or building management system. This relay architecture supports a differentiated multi-stage response to gas alarm events directly from the controller, without requiring external relay logic in the connected control system.
Two-Level Sound and Light Alarm (65–100 dB)
The BH-KZ102 implements two independent alarm thresholds — a lower-level warning and a higher-level emergency alarm — with combined sound (65–100 dB within one metre) and light output at each level. The two-level structure supports a tiered response protocol: the first alarm level triggers precautionary actions such as ventilation activation and personnel alert, while the second level activates emergency responses including isolation and evacuation procedures. This two-stage alarm architecture directly aligns with the response protocols recommended or required in gas detection installation codes of practice across commercial and light industrial applications.
DC 24V ±6V Sensor Power Supply Output
The BH-KZ102 provides DC 24V ±6V output voltage for powering connected field gas detection sensors directly from the controller. This integrated sensor power supply eliminates the need for separate 24V power supplies at field sensor locations, simplifying the installation design and reducing the component count of the detection system. The ±6V tolerance accommodates voltage drop across cable runs to remote sensor locations without requiring local voltage regulation at each detection point.
Compact Form Factor — 37 × 24 × 10cm, ≤75W
The BH-KZ102’s compact dimensions and ≤75W power consumption make it suitable for installation in locations where a larger gas controller panel would not physically fit or would exceed the available power circuit capacity. Control rooms with limited wall space, electrical cupboards, and smaller facilities management rooms can accommodate the BH-KZ102 where the larger BH-KZ103 would require dedicated panel space. The lower power draw also reduces the load on the panel power circuit, relevant for installations where multiple safety system panels share a common power supply.
Two-Wire RS485 Digital Signal Support
The BH-KZ102 supports two-wire RS485 digital signal for communication with connected MODBUS-compatible systems. Two-wire RS485 is the standard field bus wiring configuration for MODBUS industrial networks — requiring only two signal conductors to the connected system, minimising cabling costs and complexity for installations where the BH-KZ102 needs to communicate with SCADA, BMS, or DCS systems over the building’s existing RS485 infrastructure.
Technical Specifications
Model: BH-KZ102
Display: 7-inch high-definition LCD touch screen with status indicator light
Dimensions: 37 × 24 × 10cm
Weight: Approximately 7000g
System Power: ≤75W
Output Voltage: DC 24V ± 6V
Signal Input: Two-wire RS485 digital signal
Signal Output: Four sets of relay contact outputs
Digital Upload Protocol: One-way RS485, MODBUS protocol
Alarm Concentration: Two-level sound and light alarm; sound 65–100 dB within 1 metre
Working Temperature: 0°C to 40°C
Humidity: ≤95% RH (no dew)
IP Rating: Not stated — indoor installation; confirm with supplier for environmental requirements
Safety Approvals: Not stated on listing — confirm with supplier
Wireless Connectivity: Not specified — RS485 wired communication
Data Logging: Via connected MODBUS-compatible SCADA or BMS system
Battery Backup: Not specified — confirm UPS requirements with supplier
Benefits
For building managers and facilities operators in smaller commercial premises, the BH-KZ102 delivers the centralised gas detection management capability of a full industrial controller without the panel size, power demand, or installation complexity that larger systems require. A single controller managing all detection zones, displaying their status on a clear 7-inch screen, and communicating alarm events to the building management system via MODBUS gives facilities teams the visibility and control they need without the overhead of a system sized for a much larger installation.
For safety system designers specifying gas detection for light commercial buildings, multi-tenant premises, or installations with constrained panel space, the BH-KZ102’s compact form factor resolves a practical specification challenge. Four relay outputs in a package this size means the controller can manage differentiated alarm responses — local alarm, ventilation activation, gas isolation, BMS signal — from a single compact unit rather than requiring an external relay panel to expand the output capacity of a simpler alarm-only controller.
For HSE managers responsible for gas monitoring compliance across multiple smaller premises — a portfolio of commercial kitchens, car parks, or residential buildings — the BH-KZ102’s MODBUS RS485 communication enables automatic logging of alarm events into a central management platform, supporting the consistent compliance record-keeping that a multi-site portfolio requires. Rather than relying on manual log books at each site, MODBUS-connected controllers report alarm events automatically to a central system where records are maintained without requiring site visits for data extraction.
Who It’s For
Building Services Engineer — Commercial or Mixed-Use Development
You’re designing the gas safety system for a commercial or mixed-use building with gas appliances across multiple areas — ground-floor commercial kitchen, basement car park with CO monitoring, plant room with gas boilers. You need a central gas controller that manages detection across all zones, provides clear on-screen status for building management staff, controls ventilation responses through relay outputs, and connects to the building’s BMS via MODBUS. The BH-KZ102’s 7-inch touch screen, four relay outputs, and MODBUS RS485 communication cover all these requirements in a panel sized for a commercial building’s electrical installation rather than an industrial plant room.
Facilities Manager — Multi-Zone Light Commercial Premises
You manage a commercial premises with gas appliances and fixed gas detection across several areas. You need to know the status of every detection zone without visiting each area individually, and you need the system to activate ventilation automatically when an alarm triggers rather than depending on a staff response. The BH-KZ102’s single-screen multi-zone display and relay-controlled ventilation output give you operational oversight and automated response in one compact panel that fits in your existing electrical installation without requiring dedicated panel space.
HSE Manager — Multi-Site Commercial Portfolio
You’re responsible for gas safety compliance across a portfolio of commercial properties — restaurants, hotels, or serviced apartments — each with fixed gas detection installed. You need controllers at each site that log alarm events in a format your central safety management platform can receive automatically, so your compliance records are maintained without manual data extraction from each site’s controller. The BH-KZ102’s MODBUS RS485 output enables that automatic data flow to any MODBUS-compatible central monitoring platform, building a consistent audit trail across your entire portfolio.
Possible Applications
Commercial Car Parks — CO Detection System Control — Multi-level car parks require centralised CO alarm management and ventilation control across multiple detection zones. The BH-KZ102 manages zone alarm status, activates ventilation through relay outputs at the first alarm level, and triggers emergency responses at the second level, while communicating alarm events to the building management system via MODBUS.
Commercial Kitchens and Restaurants — CH4 and CO System Management — Commercial kitchens with natural gas appliances across multiple cooking stations or kitchen areas require centralised detection management. The BH-KZ102 monitors all detection zones, activates gas isolation through relay outputs when the second alarm level is reached, and provides kitchen management staff with clear zone status on the touch screen display.
Hotels and Serviced Apartments — Building Gas Safety Control — Hospitality buildings with gas installations across plant rooms, laundry facilities, and kitchen areas require a central controller for gas safety management. The BH-KZ102’s compact size fits standard electrical installation enclosures, and its MODBUS communication supports integration with hotel property management and building management systems.
Healthcare Facilities — Medical Gas and Utility Area Monitoring — Healthcare buildings with gas installations in plant rooms, boiler houses, and medical gas storage areas require centralised monitoring with automated response capability. The BH-KZ102’s relay outputs support ventilation and isolation responses, and its MODBUS connectivity enables gas alarm events to be incorporated into the facility’s healthcare technology management system records.
Educational Buildings — Gas Safety Management — Schools, colleges, and universities with gas appliances in kitchens, laboratories, and heating plant require centralised gas detection management. The BH-KZ102 provides the central controller function for multi-zone detection systems in educational buildings, with a touch screen interface accessible to facilities management staff without specialist gas detection training.
Industrial Workshops and Light Manufacturing — Light manufacturing facilities with gas-fired processes, heating systems, and utility infrastructure require fixed gas detection management that can integrate with the facility’s operational control systems. The BH-KZ102’s MODBUS RS485 output supports integration with workshop control systems and site safety management platforms.
Retail and Leisure Facilities with Gas Infrastructure — Large retail premises, leisure centres, and entertainment venues with gas appliances and heating systems in back-of-house areas require centralised gas safety management that doesn’t demand industrial panel space. The BH-KZ102’s compact form and touch screen interface are appropriate for commercial facilities management environments.
Trust & Certifications
MODBUS RTU Protocol — Universal Integration Standard
MODBUS is the most widely deployed industrial communication protocol globally, supported by virtually every SCADA platform, building management system, and safety PLC manufacturer. MODBUS RS485 in the BH-KZ102 means the controller integrates into any existing MODBUS-compatible site infrastructure as a standard device — reading gas alarm and status data without requiring proprietary software, custom protocol adapters, or manufacturer-specific integration work. For building services engineers and facilities managers who need gas detection data to appear in their BMS alongside other building system data, MODBUS RS485 is the integration standard that makes this straightforward.
Two-Level Alarm System — Codes of Practice Alignment
Two-level gas alarm systems — separating a precautionary warning threshold from an emergency action threshold — are specified or recommended in gas detection installation codes of practice across commercial and industrial sectors in the UK and internationally. The BH-KZ102’s built-in two-level alarm architecture directly matches the alarm escalation approach these standards recommend, supporting a compliant installation design without requiring external logic to implement the two-stage response.
65–100 dB Alarm Sound Output
The documented 65–100 dB alarm sound range provides installers with verified audibility data for compliance checking against the alarm audibility requirements that apply to the specific building type and occupancy. 65 dB minimum aligns with gas alarm audibility requirements for occupied commercial spaces, while the 100 dB upper capability covers noisier industrial and utility areas within the same controller specification.
Note on Safety Approvals and IP Rating
The BH-KZ102 is a wall-mounted indoor gas detection controller, not a field-installed hazardous area instrument. The field sensors connected to the BH-KZ102 require appropriate hazardous area certification for their installation locations; the controller itself is typically installed in a non-classified indoor location. Buyers should confirm applicable electrical installation approvals for their region and building type with the supplier before procurement.
Accessories & Variants
Compatible Fixed Gas Detectors (field sensors)
The BH-KZ102 connects to fixed gas detection sensors at individual monitoring points. Sensor selection should match the target gas, detection range, and hazardous area classification at each field installation point. Compatible sensors include 24V DC powered fixed gas detectors with 4–20mA or relay signal output — confirm sensor compatibility with our technical team for your specific installation design.
External Alarm Beacon
External audible/visual alarm beacons connected to the BH-KZ102’s relay outputs extend alarm coverage to areas remote from the controller panel — relevant for larger premises where the controller’s onboard alarm may not be audible or visible from all monitored zones.
UPS Battery Backup
For installations requiring continuous gas monitoring during mains power interruptions, an external uninterruptible power supply (UPS) maintains BH-KZ102 operation and 24V sensor power during outages. Specify UPS capacity based on connected sensor count and required backup duration for your site’s safety case requirements.
RS485 to Ethernet or TCP/IP Gateway
For BMS or SCADA systems communicating over Ethernet or IP networks, an RS485-to-Ethernet gateway converts the BH-KZ102’s RS485 MODBUS signal to a network-compatible format, enabling integration with IP-based building management platforms without replacing the RS485 field wiring infrastructure.
BH-KZ102 vs BH-KZ103 — Selecting the Right Controller
BH-KZ102 — 7-inch touch screen, 37 × 24 × 10cm, ≤75W, approximately 7kg. Suited to smaller commercial buildings, light industrial premises, and installations with space or power constraints.
BH-KZ103 — 10.1-inch touch screen, 43 × 29 × 9.5cm, ≤120W, approximately 8kg. Suited to larger facilities, process plants, and installations where a larger display and higher power capacity are appropriate for the scale of the detection system.
Both controllers share the same RS485 MODBUS protocol, four relay output architecture, two-level alarm system, and 24V sensor power supply — making them interchangeable at the system design level with screen size and power rating as the primary selection criteria.
Request a Quote or System Design Consultation
If you’re specifying a central gas detection controller for a commercial building, light industrial facility, or multi-site safety programme — and you need MODBUS integration, four-relay control outputs, and a clear operator interface in a compact, energy-efficient package — the BH-KZ102 is worth evaluating against your installation requirements.
Speak with our team to discuss your detection zone layout, sensor compatibility, relay output configuration, and MODBUS integration needs. We can also advise on the BH-KZ102 vs BH-KZ103 selection for your specific application, and provide pricing for single-site or multi-site supply as part of a complete fixed gas detection system. We work with building services engineers, facilities managers, HSE teams, and procurement leads across commercial, healthcare, education, and light industrial applications.
