01
Central controller
M-Controller
Programmable multi-channel gas detection controller with distributed sensing, alarm processing, relay control, communications, configuration, and system integration.
View project →XBitWave
Engineering Portfolio
Xiangyang ZhengPrincipal Engineer
30+ Years of Engineering Excellence
20+ Commercial Product Platforms
From Concept to Worldwide Deployment
20+ Commercial Product Platforms
From Concept to Worldwide Deployment
30+Years Engineering Experience
20+Commercial Product Platforms
MillionsOperating Hours in the Field
GlobalInstallations Worldwide
UL 2075Certified Products
BACnet BTLPR26 Listed
The differentiator
Not just an engineer. A product creator.
Very few engineers can truthfully say they personally designed an entire commercial product — from the first requirement to the units shipping off the line. Across the portfolio below, I did exactly that.
Entire products designed by me✓System Architecture
✓Electronics
✓PCB Layout
✓Embedded Firmware
✓Bootloader
✓Android NFC App
✓Windows Config Software
✓SolidWorks Mechanical
✓Test Fixtures
✓QA Procedures
✓Manufacturing Docs
✓User Manuals
✓UL Certification Support
✓Field Support
✓Product Branding
✓Full Product Rebranding
Technical expertise
Full-stack, from silicon to shipment
Six disciplines, delivered in-house by one engineer.
Electronics
Analog Circuit DesignPrecision Signal ConditioningSensor InterfacesEMC DesignPower SuppliesPCB Layout
Embedded
Embedded CAVRSTM32BootloadersRTOSLow Power
Communications
BACnet MS/TPBACnet/IPModbus RTURS-485NFCSPIUARTI²CUSB
Software
WindowsAndroidJavaC#PythonSQLiteNFC AppsConfig Tools
Mechanical
SolidWorksInjection Mold DesignSheet MetalOptical Bench DesignExplosion-proof Housing
Industrial
Gas DetectionNDIRPIDElectrochemicalCatalytic BeadFunctional Safety
Engineering philosophy
One engineer, the complete lifecycle.
Great industrial products are created when a single engineer truly understands the complete engineering lifecycle — from the first concept to the last unit shipped and supported in the field.
ConceptArchitectureElectronicsPCBFirmwareMechanicalSoftwareCertificationManufacturingField Support
Featured work
Flagship products
Designed end to end — electronics, firmware, software, mechanics, and certification.
Refrigerant safety · Industrial IoT
QVRF
Modern refrigerant detection platform with embedded control, a BACnet stack ported from the open-source BACnet Stack project, NFC commissioning, and an Android configuration and firmware-download app.
BACnet · BTL PR26Android NFC ConfigModbusCloud-ready IoT
See it in the lineup →
Central controller
M-Controller-II
Programmable multi-channel gas-detection controller and alarm system — distributed sensing, relay logic, field communications, and system integration, with matching PC configuration software.
32 Digital Sensors8 Analog InputsBACnetModbusRelay Logic
Read the case study →
Explosion-proof transmitter
Q8 / B8
Explosion-proof toxic and combustible gas transmitter for hazardous, Class I Division 2 areas — digital display with STEL/TWA/peak, tri-colour alarm backlight, and non-intrusive calibration across electrochemical, catalytic-bead, PID, and infrared sensors.
Detects 30+ target gases — oxygen, combustible/LEL, toxic & infrared — across 4 sensor technologies. See the full gas list →
Class I Div 2Explosion-proofModbus / BACnet MS/TP4-20 mA
See it in the lineup →
Gas transmitter family · UL 2075 certified
Q5 / B5
Fixed gas-detection transmitter platform carrying full UL 2075 certification — a rigorous gas-and-vapor-detector safety listing that relatively few products achieve. Designed end to end: electronics, enclosure, firmware, an embedded BACnet MS/TP stack on the B5, calibration workflow, and production test.
Detects 30+ target gases — oxygen, combustible/LEL, toxic & infrared — across 4 sensor technologies. See the full gas list →
UL 2075 CertifiedUL 61010Embedded CBACnet MS/TP
See it in the lineup →
Designed end-to-end
The full product lineup
Gas detection · Controllers · BACnet gateways · Sampling systems
02
Central controller
Q-Controller
Universal 256-sensor gas detection controller and alarm unit, interfacing with up to 128 remote digital transmitters and 128 analog inputs while driving 128 relay and 128 analog outputs. Touchscreen HMI with Modbus communications.
03
Four-channel controller
Q4 Controller
Four-channel gas monitoring and control system — a microprocessor-based, field-programmable controller managing up to four QEL digital sensor/transmitters over an RS-485 smart-sensor port, with pluggable relay, 4-20 mA and RS-485 option boards in an IP66 / NEMA 4X enclosure.
04
BACnet/IP converter
BAC-Box
BACnet Application Specific Controller (B-ASC) that puts a QEL controller gas-detection system — Q-Controller, M-Controller, or Q4 Controller — onto a BACnet/IP network, bridging the controller's RS-485 field bus to Ethernet as individual BACnet objects.
05
Gas transmitter family
Q5 / B5
Fixed gas detection transmitter platform developed as a complete sensing product, including electronics, enclosure, firmware, an embedded BACnet MS/TP communication stack on the B5 variant, calibration workflow, production testing, and documentation.
06
Gas transmitter family
Q6 / B6
Networked gas transmitter platform integrating sensor interfaces, local display and controls, alarm functions, field communications, configuration tools, and manufacturing support.
07
Advanced transmitter
Q7
Industrial gas detection transmitter designed across hardware, firmware, sensing, mechanics, user interface, diagnostics, test procedures, and field-service documentation.
08
Explosion-proof transmitter
Q8 / B8
Explosion-proof toxic and combustible gas transmitter for hazardous, Class I Division 2 areas. Digital concentration display with STEL, TWA, and peak readings, a three-colour alarm backlight, and non-intrusive calibration. Q8 with 4-20 mA and RS-485 Modbus, B8 with RS-485 BACnet MS/TP.
09
Infrared refrigerant detector
QIRF-II
Infrared refrigerant detection platform combining optical and electronic design, embedded signal processing, an integrated BACnet MS/TP communication stack, calibration methods, fault diagnostics, mechanical packaging, and factory test procedures.
10
Remote display
RDF-52
Remote display and annunciation platform for distributed gas detection systems, including communications, interface electronics, embedded firmware, enclosure design, and installation documentation.
11
Refrigerant safety platform
QVRF
Modern refrigerant detection platform with embedded control, a BACnet protocol stack ported from the open-source BACnet Stack project (BTL Listed at Protocol Revision 26), fieldbus communications, NFC commissioning, configurable manufacturing data, diagnostics, and Android-based configuration and firmware download.
12
Sample-draw system
SCS-1
One-channel sampling and conditioning system that draws air from a remote area or confined space for analysis. A motorised pump with clogging and water detection, a precision flow meter with direct-reading scale, and a replaceable in-line disk filter, all housed in a NEMA 4X enclosure for continuous operation in harsh environments.
BACnet protocol engineering
An embedded BACnet stack across the product line
I ported and integrated the BACnet communication stack — based on the open-source BACnet Stack project — on the B5, QIRF-II, and QVRF transmitters, covering the MS/TP data link, object model, standard services, alarming, and device configuration. The QVRF implementation was independently verified and achieved BTL Listing at BACnet Protocol Revision 26 (PR26). The same work also drives the BAC-Box, a BACnet Application Specific Controller that presents a QEL controller gas-detection system (Q-Controller, M-Controller, or Q4 Controller) as individual BACnet objects on a BACnet/IP network.
BTL ListedProtocol Revision 26MS/TPBACnet/IP (BAC-Box)Object model & services
* Certification scope depends on the specific product model, sensor, revision, and listing. Selected products achieved UL 2075 certification, while many products were evaluated or listed to UL 61010 requirements. BTL Listing applies to the specific QVRF product and revision submitted to the BACnet Testing Laboratories. Certification marks should only be shown with the exact approved model and listing information.
System network
Accessories & expansion modules
Relays · I/O · Annunciators · Switches
The controllers anchor a larger detection network. I designed the surrounding modules that expand I/O, drive remote relays and annunciators, and distribute switching and display across a site.
M-Controller family
Remote relay module — up to 11 modules give a maximum of 99 relays.
Remote display with on-board relays.
LED annunciator panel.
Remote switch that commands the M-Controller or Q4 Controller to activate relays.
Q-Controller DIN-rail modules
8-channel analog input module (up to 16).
8-channel analog output module (up to 16).
4-channel relay input module (up to 31).
4-channel relay output module (up to 31).
DIN-rail mounting box for expansion modules.
Remote switch for the Q-Controller.
Software ecosystem
Full-stack, hardware to app
The tools that complete each product — all designed in-house.
Windows / PC
Configuration & Diagnostics
PC applications for device setup, network configuration, calibration, commissioning, diagnostics, and production support — including the QVRF-Mate tool and the M-View system software.
- Device configuration and cloning
- Calibration and service workflows
- Communication and diagnostic tools
- Factory and field support
Android / NFC
QVRF ConfigTools
An Android NFC application for fast commissioning and service of QVRF devices — configuration, cloning, calibration, diagnostics, and firmware download over NFC.
- Configuration of unpowered devices via NFC
- Batch cloning and commissioning
- Password-controlled service functions
- NFC-based firmware transfer and update
Certifications & compliance
Engineered to pass, not just to work
My role spanned design-for-compliance through the full evaluation, testing, and listing of these products.
UL 2075
Gas and vapor detector safety standard. Led product design and engineering support through evaluation and listing of certified detectors.
UL 61010
Safety for measurement, control, and laboratory equipment. Engineered products to meet construction and test requirements.
CSA
Canadian certification. Supported evaluation and compliance for the controller and transmitter platforms.
CE
European conformity. Ensured products met CE and EMC directives for the European market.
BACnet BTL
BACnet Testing Laboratories listing. Ported and verified the BACnet stack — QVRF achieved BTL Listing at Protocol Revision 26.
EMC & Environmental
Designed for and supported EMC immunity/emissions and environmental qualification — temperature, humidity, and vibration.
Certification scope depends on the specific product model, sensor, revision, and listing. Marks should only be shown with the exact approved model and listing information.
Career & product timeline
From the 8088 to Industrial IoT
Nearly four decades of products taken from concept to production.
1988
Industrial PC · Intel 8088
Designed an industrial PC built around the Intel 8088 CPU.
1990
Power-Plant Monitoring System
Voltage, current and power-delivery monitoring system for power plants — the year I graduated in Computer Application & Engineering.
1992
Three-Colour LED Billboard
Large-format full-colour LED billboard display system.
1994
VCD Player
Consumer VCD player development.
1995
Fixed Combustible Gas Detector
Entered gas detection with a fixed combustible gas detector.
1998
Portable Gas Instruments
Handheld portable gas-detection instruments.
2002
M-Controller & M-Relay
Multi-channel gas-detection controller with remote relay expansion modules.
2003
M-View Software
Windows configuration and monitoring software for the M-Controller system.
2005
M-Logger & M-Net
Data logging and networking for distributed gas-detection systems.
Transmitters
Q5 / B5 · Q6 / B6 · Q7
Fixed gas-detection transmitter families, developed as complete sensing products.
Infrared sensing
QIRF-II
NDIR refrigerant detection with embedded signal processing.
System expansion
RDF-52
Remote display and annunciation across distributed systems.
Industrial IoT
QVRF NFC
Refrigerant safety platform with NFC commissioning and an Android app.
Brand transition
QEL → Greystone Rebranding
Full product-line rebrand across hardware, software, and documentation.
Today
BACnet BTL — PR26 Listed
Independently verified BACnet interoperability at Protocol Revision 26.
Innovation
Technologies I've engineered into products
Advanced NDIR
Electrochemical Sensors
PID Sensors
NFC Commissioning
BACnet Interoperability
Cloud Connectivity
Industrial IoT
Machine Diagnostics
Auto Calibration
Functional Safety
About
Xiangyang Zheng
Principal Engineer · Product Creator
I am a Principal Engineer specializing in industrial gas detection, embedded systems, safety instrumentation, and Industrial IoT.
Throughout my career — since 1990, when I graduated in Computer Application & Engineering — I have led the complete development of multiple commercial products, from concept and architecture through electronics, firmware, mechanical design, certification, manufacturing, and global deployment.
My expertise spans analog electronics, precision sensor interfaces, embedded firmware, Windows and Android software, industrial communication protocols, and safety-certified product development — and I later led the complete rebranding of this portfolio from QEL to Greystone. Product names, trademarks, certification marks, and commercial materials remain the property of their respective owners.
Contact
Let's build the next product from concept to production.
Open to principal engineering leadership, product development, and consulting in gas detection, embedded systems, and Industrial IoT.
xyzheng69@hotmail.com