Dwyer Series MSX Magnesense Differential Pressure Transmitter

Overview

The Dwyer MSX Magnesense Differential Pressure Transmitter is a compact, wall or duct-mountable instrument built to measure low differential air and gas pressures in building automation and industrial ventilation systems. It uses Dwyer’s proprietary Magnesense micro-machined silicon sensor, a technology developed to hold accuracy and long-term drift performance well beyond conventional diaphragm sensors in the low-pressure range. With 32 field-selectable ranges spanning 0.1 in w.c. up to 28 in w.c. (25 Pa to 7,000 Pa, 2.5 to 700 mm w.c.), unidirectional or bidirectional, one Dwyer MSX transmitter covers what previously required several fixed-range instruments, which simplifies spares holding and commissioning on multi-zone HVAC projects.

Seven Star LLC is an authorized supply partner for Dwyer Instruments in Oman, and stocks the Dwyer MSX Magnesense transmitter for HVAC contractors, MEP consultants, and facility engineering teams across Muscat, Sohar, Duqm, and the broader GCC. Every unit shipped from Seven Star is supported with application guidance on range selection, output configuration, and mounting orientation, so building-services and process teams get a transmitter that is set up correctly for their static-pressure or airflow-control loop from day one, not a boxed part with no local backup.

Dwyer MSX Magnesense Key Features

The Dwyer MSX Magnesense transmitter is built around a small set of features that matter most to HVAC and building-automation engineers: range flexibility, dual output, and a rugged low-drift sensor.

• 32 field-configurable ranges – selectable spans from 0.1 in w.c. to 28 in w.c., unidirectional or bidirectional, covering most duct static pressure, room pressurization, filter-differential, and fan-status applications with one part number.
• Magnesense micro-machined silicon sensor – delivers ±1% full-scale accuracy with strong long-term stability and low temperature drift compared to standard diaphragm-based low-pressure sensors.
• Dual output signal – simultaneous 4–20 mA current and 0–5 or 0–10 VDC voltage output, field-selectable, so the same unit wires into current-loop or voltage-input controllers without ordering a different model.
• Optional integral LCD display – local digital readout of the measured differential pressure in engineering units, useful for balancing and commissioning without a separate meter.
• NEMA Type 4X / IP66 enclosure – UL94 V-0 rated and UL 2043 plenum rated, suited to plant rooms, rooftop units, and mechanical spaces exposed to dust and washdown.
• Wall or duct mounting – compact footprint with a removable cover for wiring access, and pressure ports sized for standard flexible tubing.

Applications

The Dwyer MSX Magnesense transmitter is applied wherever a building or process system needs a reliable, low-range differential pressure signal: VAV and CAV duct static pressure control, air handling unit filter-clog monitoring, cleanroom and laboratory room pressurization, fan proving and fan-failure alarms, and pressure-independent damper control loops feeding a building management system (BMS). Its dual current/voltage output makes it equally suited to DDC controllers, PLC analog inputs, and legacy pneumatic-to-electric retrofit panels.

In Oman and the GCC, Seven Star LLC supplies the Dwyer MSX Magnesense to MEP contractors, hospital and hotel facility teams, and industrial plants that need dependable low-pressure monitoring under high ambient temperatures and dust loading — conditions where sensor drift and enclosure ingress protection matter more than in temperate climates. Because Seven Star holds authorized Dwyer Instruments stock locally, replacement units and range reconfiguration support are available without the long lead times of importing single pieces, which keeps HVAC commissioning schedules and critical-space pressurization compliance on track.

Installation & Configuration Notes

Commissioning a Dwyer MSX transmitter correctly starts with range and output selection before power is applied: the internal DIP-switch bank sets the active pressure span and direction, while a second set of jumpers or switches selects between the 4–20 mA and 0–10 VDC output, or enables both simultaneously where the controller supports it. Zeroing is performed with both pressure ports open to atmosphere and the zero push-button held for three seconds, after which the transmitter takes a further three seconds to process the new reference. One practical advantage of the Magnesense sensing element is that it is not position sensitive: Dwyer states that the measurement is unaffected by orientation, so the enclosure can be mounted whichever way the duct, wall or DIN rail location makes most convenient without applying a gravity offset correction. High- and low-pressure ports are clearly marked, and 1/8 in, 3/16 in, 1/4 in, 5 mm or 6 mm ID flexible tubing routes each port to its respective tap point on the duct, filter bank, or room boundary being monitored.

Seven Star’s technical team assists Oman-based contractors with range selection at the quotation stage, so the Dwyer MSX Magnesense arrives on site pre-configured for the specified pressure band wherever the project schedule allows, reducing commissioning time for large HVAC rollouts and hospital or data-center pressurization cascades.

Dwyer MSX Magnesense Specifications

Key specifications of the Dwyer MSX Magnesense Differential Pressure Transmitter:

• Service: Air and non-combustible, compatible gases
• Pressure ranges: 32 field-selectable ranges, 0.1 to 28 in w.c. (25 to 7,000 Pa; 2.5 to 700 mm w.c.), unidirectional or bidirectional
• Accuracy: ±1% of full scale output
• Long-term stability: ±1% FSO per year
• Response time: instantaneous by default, 3 s selectable
• Operating temperature: -20 to 70°C (-4 to 158°F)
• Weight: 230 g
• Output signal: 4–20 mA (2-wire), 0–5 VDC or 0–10 VDC (3-wire), field-selectable, with simultaneous current and voltage output supported
• Loop resistance: 0 to 1250 Ω maximum on current output; 1 kΩ minimum load on voltage output
• Power supply: 10–36 VDC for 2-wire 4–20 mA operation; 17–36 VDC or 21.6–33 VAC for 3-wire voltage output
• Power consumption: 21 mA maximum (0.5 W DC / 0.5 VA AC)
• Enclosure rating: NEMA Type 4X / IP66, UL94 V-0 rated, UL 2043 plenum rated
• Maximum operating pressure: 3.6 psi on the lower range groups, 6 psi on the higher range groups; burst pressure 6 psi
• Process connection: two stepped barbed ports accepting 1/8 in, 3/16 in, 1/4 in, 5 mm and 6 mm ID flexible tubing
• Electrical connection: 1/2 in NPS female conduit entry with screw terminal block, 26–16 AWG
• Display: optional integral LCD indicator
• Mounting: wall or duct mount
• Approvals: CE marked, UL 2043 plenum rated, UL94 V-0, BTL listed

Range Groups and Span Selection on the Dwyer MSX

The 32 selectable spans of the Dwyer Series MSX Magnesense are not one continuous list but five range groups, and choosing the right group at the order stage is what determines how much of the instrument accuracy is actually usable on a given duty. Group 0 covers 0.1 to 0.5 in w.c. (25 to 125 Pa, 2.5 to 12 mm w.c.) for the very low differentials seen in room pressurisation cascades. Group 1 extends the same low end to 1 in w.c. (25 to 250 Pa). Group 2 spans 1 to 5 in w.c. (250 to 1,250 Pa), Group 4 spans 1 to 15 in w.c. (250 to 4,000 Pa), and Group 3 reaches the top of the family at 10 to 28 in w.c. (1,000 to 7,000 Pa) for high static duct pressure and heavily loaded filter banks. Within the chosen group the span is then set in the field, unidirectional or bidirectional.

Overpressure capability follows the group as well: the two lower groups carry a maximum operating pressure of 3.6 psi while the higher groups accept 6 psi, with a 6 psi burst rating across the family. That is the number to check before a transmitter is piped across a filter bank that can be isolated and pressure-tested, or across a fan that can produce a large shut-off head. Because accuracy is quoted as ±1% of full scale output rather than of reading, and long-term stability as ±1% FSO per year, selecting the narrowest group that comfortably contains the working differential is the single most effective thing a commissioning engineer can do to tighten a control loop that uses a Dwyer MSX Magnesense as its feedback element.

Request a Quote for Dwyer Series MSX Magnesense Differential Pressure Transmitter

Seven Star LLC supplies the Dwyer Series MSX Magnesense Differential Pressure Transmitter to HVAC contractors, MEP consultants and plant engineering teams throughout Oman and the GCC. Contact the instrumentation division for a formal RFQ, to confirm current regional warehouse stock, to obtain the full Dwyer technical datasheet and installation manual, or to have our engineers recommend the correct range group, output type and mounting kit for your duct static, room pressurisation or filter-monitoring application. As an authorized Dwyer Instruments partner for Oman and the GCC, Seven Star LLC supplies genuine hardware with calibration traceability and local configuration support.

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