Mastering HTTP/HTTPS APIs takes far more than sending requests. This article covers RESTful core semantics, three-tier authentication (API Key / Bearer Token / mTLS), JSON batching strategy, idempotent retries, store-and-forward, and certificate management — a systematic guide to cloud data upload for building automation and energy monitoring projects.

Mastering MQTT takes far more than connect, publish, subscribe. This article dives into MQTT's core: the triple decoupling value of pub/sub and topic design principles; the semantics, overhead, and selection decision tree of QoS 0/1/2; correct usage of sessions, retained messages, and Last Will for disconnection scenarios; and the engineering dividends of MQTT 5.0 (reason codes, shared subscriptions, message expiry).

OPC UA gives data semantics through information modeling, guards communication boundaries with built-in security, and embraces cloud-native architecture with PubSub. This article explores OPC UA technical architecture and its implementation in smart buildings and energy monitoring.

When traditional building protocols like Modbus and BACnet fall short of high-speed control demands, PROFINET and EtherNet/IP from industrial automation are entering smart buildings. This article compares the technical architectures, real-time performance, and application scenarios of both protocols, with deployment recommendations based on typical cases such as chiller plant control and power distribution monitoring.

How to choose among Zigbee, WiFi, and Bluetooth BLE? This article provides a systematic comparison across data rate, power consumption, networking capabilities, and application scenarios, with practical hybrid networking recommendations for smart building projects.

MQTT has become the de facto standard for IoT sensor data delivery to the cloud. This article explains the MQTT publish/subscribe architecture, QoS levels, Will and Retained messages, and shares practical engineering experience on system architecture design, TLS security hardening, and message payload design for sensor MQTT integration.

Modbus and BACnet are the two cornerstones of building automation communication. This article comprehensively covers protocol principles, data models, comparative analysis, and engineering best practices for Modbus RTU/TCP modes and the BACnet object model, helping you build robust building communication architectures.

With a market flooded by multi-in-one environmental sensor products, how do you select the solution that truly matches your project? This article provides a practical selection guide covering integration tiers (parameter/algorithm/system level), six core selection dimensions, typical building application scenarios, and deployment practices.

Current sensors are the "nerve endings" of building energy monitoring systems. This article comprehensively analyzes current transformers, Hall effect sensors, shunt resistors, and Rogowski coils from four dimensions: working principles, type selection, building applications, and deployment practices.