The Fischer Mess DE49B20040BH00MW is a specialized explosion-proof digital differential pressure transmitter belonging to the heavy-duty DE49 Series manufactured by FISCHER Mess- und Regeltechnik GmbH (Germany) – a world-renowned leader in precision instrumentation for hazardous and demanding operating environments. The instrument is engineered specifically to measure positive overpressure, negative under-pressure, and differential pressure in gaseous media across explosive atmospheres certified under ATEX / IECEx guidelines (Zone 1, Zone 2 for gas environments; Zone 21, Zone 22 for combustible dust atmospheres).

At the heart of the transmitter is a highly sensitive piezoresistive silicon measuring cell designed to ensure exceptional measurement accuracy, rapid response dynamics, and outstanding zero-point long-term stability across its bidirectional symmetrical span of -25 mbar to +25 mbar (-2.5 kPa to +2.5 kPa). The transmitter outputs an intrinsically safe 4-20 mA analog signal via a 2-wire loop-powered configuration, enabling seamless deployment through certified Zener barriers or galvanic isolators into hazardous zones. A key feature of model DE49B20040BH00MW is the integration of an industrial M12 circular connector, which delivers vibration-proof electrical contact, simplified field cabling, and complete elimination of spark risks. Encased in a rugged, anti-static housing rated to IP65 ingress protection standards, it represents the ultimate instrumentation choice for combustible dust extraction systems, solvent-processing cleanrooms, paint spray booths, and explosion-proof HVAC/AHU ventilation systems.

• Manufacturer: FISCHER Mess- und Regeltechnik GmbH
• Brand Origin: Germany
• Full Order Code: DE49B20040BH00MW
• Product Classification: Explosion-Proof Digital Differential Pressure Transmitter (DE49 Series)
• Explosion Protection Certification: ATEX / IECEx certified for hazardous environments (Gas Zone 1, Zone 2; Combustible Dust Zone 21, Zone 22)
• Explosion Protection Type: Intrinsic Safety Ex ia (Ex ia IIC T4 Gb / Ex ia IIIC T125°C Db)
• Sensing Principle: High-precision Piezoresistive Silicon Sensor Bridge
• Pressure Modes: Bidirectional differential pressure, positive gauge pressure, negative gauge pressure
• Service Media: Air and non-corrosive, neutral industrial gases in explosive process environments
• Nominal Measuring Range: -25 mbar to +25 mbar (-2.5 kPa to +2.5 kPa bidirectional span)
• Analog Output Signal: 4 – 20 mA (Intrinsically safe 2-wire loop-powered configuration)
• Operating Power Supply: DC 24V (Operating supply via barrier: 14 – 30 V DC)
• Measurement Accuracy: ±0.5% F.S. (Non-linearity, hysteresis, and repeatability combined)
• Long-Term Stability: ≤ ±0.2% F.S. / year
• Maximum Overpressure Proof: Proof pressure rating up to 500 mbar (50 kPa) without zero-point shift
• Process Pressure Connections: Pneumatic push-on tube connectors for 6 mm outer-diameter tubing (Ø 6 mm / 6/4 mm hose)
• Electrical Connection: Industrial M12 circular plug connector (4-pin/5-pin standard)
• Ingress Protection Rating: IP65 (Total dust protection and resistance against water jets)
• Housing Construction: Die-cast aluminum coated with epoxy finish or impact-resistant anti-static engineering polymer
• Wetted Materials: Silicon sensor element, Al2O3 aluminum oxide, chemical-resistant FKM / NBR elastomer seals
• Operating Ambient Temperature: -10°C to +60°C (Compliant with ATEX temperature class limits)
• Storage Temperature Range: -20°C to +70°C
• Mounting Configuration: Direct wall/panel mounting or specialized bracket for DIN rail/pipe mounting
• Typical Applications: Combustible dust filter differential pressure monitoring, solvent-handling cleanrooms in pharmaceutical production, explosion-proof HVAC/AHU systems, chemical storage tank ventilation, and oil & gas refinery skids