Key Features: Fischer DE91 Differential Pressure Transmitter

The Fischer DE91 is a high-accuracy digital differential pressure transmitter designed to measure positive pressure, negative pressure and differential pressure in air and neutral gases, especially in applications requiring the measurement of very small pressure differences.

Available in single-channel and dual-channel versions, it offers measuring ranges from 25 Pa up to 25 kPa, providing excellent long-term stability and high overload resistance.

The transmitter features a full-graphic LCD display with RGB colour-changing backlight, allowing operators to identify process status immediately. It can be configured with up to four alarm outputs, one or two analogue outputs, Modbus RTU or IO-Link communication, and a USB OTG interface for parameterisation using Fischer inTouch software.

Its high accuracy, flexible configuration and rugged IP65 enclosure make the DE91 an advanced solution for cleanrooms, filter monitoring, HVAC systems, airflow measurement and industrial automation.

As a Fischer distributor, Garma Electrónica highlights the DE91 as one of the most complete solutions available for low differential pressure measurement with digital communication, configurable alarms and excellent measurement stability.

Main Specifications: Fischer DE91 Differential Pressure Transmitter

• Measuring range: from 25 Pa up to 25 kPa, with unidirectional and bidirectional versions.
• Measured variable: differential pressure, positive pressure and negative pressure.
• Medium: air and neutral gases.
• Channels: single-channel and dual-channel versions.
• Analogue outputs: 0(4)-20 mA, 0-10 V, 2-10 V and 1-5 V, depending on version.
• Industrial communication: RS485 Modbus RTU or IO-Link 1.1.
• Switching outputs: up to 4 configurable outputs.
• Display: full-graphic LCD with RGB colour-changing backlight.
• Parameterisation: USB OTG interface using Fischer inTouch software.
• Linearisation: table with up to 30 points for airflow applications.
• Protection rating: IP65.
• Certification: optional ATEX approval for Zones 2 and 22.
• Maintenance: rugged, stable and maintenance-free design.

Applications and Benefits: Fischer DE91 Differential Pressure Transmitter

Cleanroom and Laboratory Pressure Monitoring

The DE91 accurately monitors extremely small pressure differences between rooms, airlocks and classified areas, helping maintain stable pressure cascades in pharmaceutical, electronics and food production facilities.

Intelligent HVAC Filter Monitoring

Its high sensitivity detects the progressive pressure drop across HEPA and process filters, enabling predictive maintenance and improving the energy efficiency of HVAC installations.

Airflow Measurement

When combined with Pitot tubes, orifice plates or other primary flow elements, the DE91 provides accurate differential pressure measurement for airflow calculation in ventilation and air-conditioning ducts.

Industrial Automation and Building Management

Modbus RTU and IO-Link communication, together with multiple analogue and alarm outputs, allow the DE91 to be integrated into PLC, SCADA and BMS systems for advanced monitoring, diagnostics and maintenance.

Competitive Advantages

With high-accuracy measurement from 25 Pa, single-channel and dual-channel versions, a colour-changing graphical display, up to four configurable alarm outputs, digital communication and optional ATEX approval, the Fischer DE91 is one of the most advanced solutions available for high-precision differential pressure applications.

Its combination of accuracy, flexibility, rugged construction and industrial communication makes it an excellent choice for HVAC, cleanrooms, industrial automation and critical process monitoring.