SIEMENS QBE3000/3100 differential pressure

SIEMENS QBE3000/3100 Differential Pressure Sensor: Precision Measurement and Engineering Practice for HVAC Systems

Introduction: Challenges and Solutions for Differential Pressure Measurement in HVAC Systems

In HVAC systems, differential pressure monitoring is a critical step in controlling filter clogging, pump/fan flow, liquid level, and valve pressure differentials. The core challenges faced by on-site engineers include medium corrosiveness, temperature drift, long-term stability, and compatibility of electrical interfaces. When it is necessary to replace old or discontinued differential pressure switches/transmitters, choosing a sensor that combines mechanical robustness and electronic accuracy becomes a top priority for system modification.

The Siemens QBE3000-D series and QBE3100-D series differential pressure sensors are designed specifically for this type of application. They are based on a unique ceramic lever measurement principle and are designed specifically for neutral and weakly corrosive gases and liquids. They are widely used as control sensors or measurement transmitters in building automation, industrial refrigeration stations, thermal pipelines, and clean air conditioning systems. This article will provide a complete professional reference from five dimensions: technical parameters, core materials, electrical connections, engineering installation, and troubleshooting.

Product series and model coding rules

The QBE3000/QBE3100 series are divided into two sub series based on output signals, each providing a total of 7 standard pressure ranges from low to high, covering the vast majority of HVAC application scenarios.

2.1 Differences in output signal types

Typical application scenarios of series output signal power supply voltage

QBE3000-D DC 0... 10 V AC 24 V ± 15% or DC 18-33 V with Siemens PLC or building control DDC controller (analog input 0-10V)

QBE3100-D DC 4... 20 mA DC 11-33 V long-distance signal transmission (>30 meters), strong anti-interference requirements, or compatible with 4-20mA input cards

2.2 Corresponding Table of Full Range Models

The following are the nominal pressure ranges (in bar and MPa) for each model, and all models have completed linearization and temperature compensation calibration before leaving the factory.

Model Code Order Number (Example) Pressure Range [bar] Corresponding Output Signal Range

QBE3000-D1 / QBE3100-D1 S55720-S173 / S179 0 … 1 0-10V / 4-20mA → 0-1 bar

QBE3000-D1.6 / QBE3100-D1.6 S55720-S174 / S180 0 … 1.6 0-10V / 4-20mA → 0-1.6 bar

QBE3000-D2.5 / QBE3100-D2.5 S55720-S175 / S181 0 … 2.5 0-10V / 4-20mA → 0-2.5 bar

QBE3000-D4 / QBE3100-D4 S55720-S176 / S182 0 … 4 0-10V / 4-20mA → 0-4 bar

QBE3000-D6 / QBE3100-D6 S55720-S186 / S187 0 … 6 0-10V / 4-20mA → 0-6 bar

QBE3000-D10 / QBE3100-D10 S55720-S177 / S183 0 … 10 0-10V / 4-20mA → 0-10 bar

QBE3000-D16 / QBE3100-D16 S55720-S178 / S184 0 … 16 0-10V / 4-20mA → 0-16 bar

Selection prompt: Confirm whether the system static pressure (the common pressure acting on both the high and low pressure sides) exceeds the allowable value of the sensor. For models with a nominal range ≤ 6 bar, the maximum allowable system pressure is 25 bar; Models with a range of ≥ 10 bar allow a maximum system pressure of 50 bar. The blasting pressure is 1.5 times the system pressure.

Core technology: Ceramic lever measurement system

Traditional differential pressure sensors often use metal strain gauges or capacitive diaphragms, but there are problems such as large temperature drift, long-term creep, and medium corrosion. The QBE3000/3100 series adopts Ceramic Lever Technology, with the following specific advantages:

Extremely low temperature sensitivity: The thermal expansion coefficient of ceramic materials is close to that of the sensor housing metal, coupled with the built-in temperature compensation circuit (TC zero point<± 0.04% FS/K, TC sensitivity<± 0.015% FS/K), resulting in minimal output drift in the full temperature range of -15~85 ℃.

No mechanical aging and creep: Ceramics have high elastic modulus and fatigue resistance, and even under long-term alternating pressure, there will be no plastic deformation or zero drift commonly seen in metal membranes. Long term stability meets the DIN EN 60770 standard and is better than ± 0.5% FS/year.

Excellent medium compatibility: The ceramic itself is corrosion-resistant, and combined with FPM (fluororubber) seals, it can be used for neutral and weakly corrosive liquids (such as dilute ethylene glycol solution, light oil) as well as humid gases.

Measurement principle description: The measured differential pressure acts on the ceramic sensing element, causing it to produce a small displacement (lever effect). This displacement is converted into an electrical signal by the internal ASIC, and then linearized, temperature compensated, and amplified to output a standard analog signal. The sensor has completed multi temperature point calibration before leaving the factory, and users do not need to calibrate it on site.

Detailed explanation of electrical parameters and interface matching

4.1 Power Supply and Consumption

QBE3000-D series: Supports a wide power supply range - AC 24 V (± 15%, 50/60 Hz) or DC 18... 33 V. When powered by AC 24V, the typical power consumption is less than 5 mA, which is very suitable for centralized power supply of AC 24V transformers commonly used in building automation.