Siemens QBE3000-D4 Differential Pressure Transmitter

The Siemens QBE3000-D4 is a differential pressure sensor designed for monitoring neutral or slightly aggressive liquids and gases. With a measuring range of 0 to 4 bar (0–4000 kPa), it is suitable for HVAC systems, pump control, filter monitoring, and industrial process measurement. The transmitter provides a 0‑10 V DC analog output signal proportional to the differential pressure. Housed in a robust aluminum enclosure, the QBE3000‑D4 features a ceramic measuring cell for high accuracy and long‑term stability, even in harsh conditions.

Technical Specifications

• Order Number: QBE3000-D4 (S55720‑S176)

• Measuring Range: 0 to 4 bar (0–400 kPa / 0–58 psi)

• Output Signal: DC 0–10 V (linear)

• Supply Voltage: AC 24 V ±20% or DC 18–33 V

• Power Consumption: Max. 1.5 VA

• Measuring Principle: Ceramic capacitive pressure cell

• Accuracy: ±1.0% of full scale (including linearity, hysteresis, repeatability)

• Process Connection: G⅛″ male thread (ISO 228‑1) with copper tube connectors (6 mm diameter)

• Pressure Ports: High side (P1), Low side (P2)

• Overload Capacity: 12 bar (both sides)

• Burst Pressure: 25 bar

• Media Compatibility: Neutral or slightly aggressive liquids, gases, and air

• Enclosure Material: Aluminum (housing), stainless steel (pressure port)

• Protection Rating: IP65 (when properly installed)

• Cable Connection: 2‑meter shielded cable or M12 connector (variant dependent)

• Operating Temperature: -25°C to +70°C

• Storage Temperature: -40°C to +85°C

• Weight: 0.65 kg

• Dimensions (W × H × D): 67 mm × 143 mm × 40 mm

Functional Description

The sensor measures the pressure difference between its two ports (P1 high side, P2 low side). The internal ceramic cell converts the pressure into a proportional analog voltage signal (0–10 V). For example, at 0 bar differential, the output is 0 V; at 4 bar differential, the output is 10 V. The output signal can be scaled through wiring (no user calibration needed). The sensor compensates for temperature variations and includes reverse polarity protection.

Installation and Wiring

The QBE3000‑D4 is typically mounted using the supplied bracket and screws. The pressure ports accept 6 mm copper or plastic tubing, secured with the included threaded fittings. Connect the two pressure lines to P1 (higher pressure) and P2 (lower pressure). For the electrical connection, connect the brown wire to 24V AC/DC, the white wire to ground, and the green wire to the analog input of a PLC or controller. The cable shield should be grounded at the controller end only.

HVAC and Industrial Applications

The transmitter is used to measure differential pressure across pumps, valves, and filters (e.g., monitoring clogged filters), to measure flow rate using an orifice plate (with square root extraction in the controller), and to monitor liquid level in pressurized tanks (difference between hydrostatic pressure and tank pressure). It is also suitable for monitoring compressor lubrication oil circuits and gas distribution lines.

Environmental and Compliance

The QBE3000‑D4 is CE marked and RoHS compliant. It meets the requirements of EN 60730‑1 for automatic electrical controls. The housing is IP65‑rated when the cable gland is properly sealed. The sensor is designed for indoor and outdoor installation (weather‑protected) with an altitude up to 2000 m.

Conclusion

The Siemens QBE3000-D4 differential pressure transmitter provides a reliable, linear 0‑10 V output, making it easy to integrate into PLC‑based monitoring and control systems for HVAC and industrial applications.