Pressure measurement is one of the most critical parameters in industrial automation, machine engineering, environmental systems, energy plants and process applications. Selecting the correct pressure transmitter directly affects measurement accuracy, process reliability, equipment safety and long-term operational performance.
The BD|SENSORS DMP 331 and DMK 331 industrial pressure transmitters are designed for demanding industrial pressure measurement tasks. Although both devices are used for pressure monitoring and process control, they are optimized for different application conditions. DMP 331 is a stainless steel sensor pressure transmitter for low-pressure industrial applications, while DMK 331 uses a ceramic sensor and is especially suitable for pasty, polluted or aggressive media.
What Is DMP 331?
The DMP 331 is an industrial pressure transmitter designed for low-pressure applications. It uses a stainless steel sensor and is suitable for industrial areas where the process medium is compatible with stainless steel 1.4404 / 316L or 1.4435 / 316L.
Its modular structure allows different stainless steel sensors, electronic modules, electrical connections and mechanical connections to be combined. This makes DMP 331 a flexible pressure measurement solution for a wide range of industrial applications.
Typical areas of use include plant and machine engineering, environmental engineering such as water, sewage and recycling systems, and the energy industry.
DMP 331 Technical Highlights
The DMP 331 covers nominal pressure ranges from 0–100 mbar up to 0–60 bar. It offers standard 4–20 mA two-wire output, with optional 0–20 mA and 0–10 V three-wire outputs.
According to IEC 61298-2, the standard accuracy is 0.35% FSO for nominal pressure ranges from 0.4 bar and above. Optional accuracy versions of 0.25% FSO and 0.1% FSO are also available. For nominal pressure ranges below 0.4 bar, the standard accuracy is 0.50% FSO.
The transmitter offers excellent long-term stability, specified as ≤ ±0.1% FSO per year at reference conditions. Response time is fast, with ≤10 ms for two-wire output and ≤3 ms for three-wire output.
Strong Thermal Behavior and Long-Term Stability
One of the key strengths of DMP 331 is its thermal performance. The product is designed for reliable pressure measurement in low-pressure ranges where temperature changes can have a significant influence on measurement accuracy.
With its stable stainless steel sensor structure, DMP 331 provides dependable long-term operation in industrial process environments. This makes it suitable for applications where repeatable pressure data is required over long operating periods.
DMP 331 for Low-Pressure Applications
Low-pressure applications require sensitive and stable measurement technology. DMP 331 is specifically positioned for this need. Its available measuring ranges start from 100 mbar, making it suitable for applications such as level measurement, water systems, air pressure monitoring, environmental processes and low-pressure machine systems.
The pressure port option G 1/2" flush from 100 mbar is also an important feature for applications where a flush diaphragm connection is preferred.
Optional Versions of DMP 331
DMP 331 can be supplied with several optional versions. An intrinsically safe Ex ia version is available for gas and dust atmospheres. A SIL 2 version according to IEC 61508 / IEC 61511 is also available for safety-related applications.
Other options include welded pressure sensor versions, customer-specific versions and drinking water certification according to DVGW and KTW. The welded version is available for selected pressure ports and pressure ranges, supporting applications where elastomer sealing is not preferred.
What Is DMK 331?
The DMK 331 is an industrial pressure transmitter with a ceramic sensor. It is designed especially for pasty, polluted or aggressive media, as well as oxygen applications in low-pressure ranges.
The ceramic sensor technology makes DMK 331 suitable for processes where the measured medium may not be ideal for conventional stainless steel sensor designs. Its construction provides a reliable solution for difficult fluids, contaminated media and selected aggressive applications.
Typical areas of use include plant and machine engineering, energy industry, environmental engineering such as water, sewage and recycling, and medical technology.
DMK 331 Technical Highlights
The DMK 331 covers nominal pressure ranges from 0–400 mbar up to 0–600 bar. It offers standard 4–20 mA two-wire output, with optional 0–20 mA and 0–10 V three-wire outputs.
Accuracy according to IEC 61298-2 is ≤ ±0.5% FSO. Long-term stability is specified as ≤ ±0.3% FSO per year at reference conditions. Response time is ≤10 ms for two-wire output and ≤3 ms for three-wire output.
The medium temperature range is -40 °C to +125 °C. For PVDF pressure port versions, the permissible medium temperature is -30 °C to +60 °C.
Ceramic Sensor for Difficult Media
The most important difference of DMK 331 is its ceramic diaphragm. The diaphragm material is Al₂O₃ 96% ceramic, which offers good resistance for many demanding media conditions.
This makes DMK 331 a strong option for pressure measurement in pasty, polluted or aggressive media. For aggressive media, a G 1/2" open port PVDF pressure port option is available for nominal pressure ranges up to 60 bar.
The transmitter can also be configured for oxygen applications up to 25 bar / 150 °C, using an FKM Vi 567 O-ring with BAM approval.
Special Pressure Port Options
DMK 331 provides special mechanical connection options for challenging process conditions. The G 1/2" flush pressure port is suitable for pasty and polluted media because it reduces the risk of clogging at the pressure connection.
The G 1/2" open port PVDF option is designed for aggressive media. This provides additional flexibility for chemical, wastewater, environmental and process applications where standard metallic wetted parts may not be suitable.
Shared Industrial Advantages
Both DMP 331 and DMK 331 are designed with industrial reliability in mind. They offer short-circuit protection, reverse polarity protection and electromagnetic compatibility according to EN 61326.
Both models provide strong mechanical stability, with vibration resistance of 20 g RMS from 10 to 2000 Hz and shock resistance of 500 g / 1 ms half sine according to relevant DIN EN standards.
Both transmitters also offer multiple electrical connection options, including ISO 4400, Binder series 723, M12x1 metal connector, cable outlet, cable outlet with ventilation tube and compact field housing options.
Explosion Protection and SIL Options
Both transmitters can be supplied with intrinsically safe versions for hazardous areas when configured with 4–20 mA two-wire output. The ATEX and IECEx versions support use in gas and dust atmospheres, depending on the model and pressure port configuration.
SIL 2 versions according to IEC 61508 / IEC 61511 are also available, making both transmitters suitable for safety-related pressure measurement tasks in industrial automation systems.
Choosing Between DMP 331 and DMK 331
The choice between DMP 331 and DMK 331 depends mainly on the process medium and measuring range.
DMP 331 is the right choice for low-pressure applications where stainless steel wetted parts are compatible with the medium. It offers higher optional accuracy, excellent thermal behavior and very good long-term stability.
DMK 331 is preferred when the process involves pasty, polluted or aggressive media, or when ceramic sensor technology is more suitable for the application. It also offers a much wider nominal pressure range up to 600 bar and special pressure port options such as flush and PVDF open port connections.
Typical Application Areas
DMP 331 is suitable for plant engineering, machine engineering, water systems, sewage systems, recycling applications, energy systems and general industrial pressure or level measurement tasks.
DMK 331 is suitable for plant and machine engineering, energy industry, environmental engineering, wastewater processes, aggressive media applications, medical technology and oxygen applications.
Both transmitters can be integrated into PLC systems, control panels, monitoring systems and process automation networks using analog current or voltage outputs.
Conclusion
The BD|SENSORS DMP 331 and DMK 331 industrial pressure transmitters offer reliable pressure measurement for different industrial requirements.
DMP 331 is optimized for low-pressure applications with stainless steel sensor technology, excellent long-term stability and optional high accuracy. DMK 331 is designed for more challenging media conditions, using ceramic sensor technology for pasty, polluted or aggressive media and oxygen applications.
Together, these two models provide flexible and dependable pressure measurement solutions for machine builders, process engineers, environmental systems and industrial automation applications.