Dew Point Sensor-AMT-Ex Dewpoint Transmitter

A robust solution for continuous moisture measurement in process gases and compressed air, featuring ultra-high capacitance aluminium oxide sensing technology. Certified intrinsically safe to ATEX and IECEx standards for use in hazardous areas.

Our AMT-Ex Dewpoint Transmitter is a compact 3-wire, 4-20 mA transmitter that offers continuous online moisture measurement across various dewpoint ranges from -120 °C to +20 °C — accurate to ±2 °C (±3.6 °F) dewpoint.

Its advanced RISC microprocessor circuitry provides high resolution and sophisticated self-diagnostics. Equipped with a unique AutoCal span correction feature, the AMT-Ex Dewpoint Transmitter facilitates field calibrations and span checks, ensuring optimal accuracy between laboratory calibrations. The rugged stainless steel construction provides protection to IP66 / NEMA 4X, with the transmitter’s electrical connections made via a secure industrial connector.

Key features

Certified intrinsically safe to IECEx and ATEX standards for use in potentially hazardous/explosive atmospheres

Ultra-high capacitance aluminium oxide sensing technology for exceptional sensitivity, speed of response, accuracy, repeatability and stability

Factory configured for output in various moisture units: °C or °F dewpoint, ppm(V), ppb(V), g/m³, and lb/MMSCF

Withstands a maximum pressure of 35,000 kPa (350 bar), allowing use in extreme environmental conditions

Easy installation and operation with minimal maintenance requirements

Optional sensor holder/sample cell for optimal sampling conditions and easy removal for annual calibration without process interruption

Supplied with a calibration certificate traceable to National and International Humidity Standards, ensuring reliability and compliance

For flexible installation, the hygrometer can be sited up to 1000 metres away from the dewpoint transmitter

Compatible with the DS1200 and DS4000 hygrometer displays

 

General

Sensor/Transmitter Type               3 Wire 4-20 mA Intrinsically Safe Dewpoint Transmitter

Documentation Instruction manual, calibration certificate

Sensor

Sensing Element               Ultra-High Capacitance – Aluminium Oxide Type

Dewpoint Range               Overall range offered between -120 °C to +20 °C (-184 °F to +68 °F) dewpoint.

-120 °C to +20 °C (-184 °F to +68 °F)

-110 °C to -20 °C (-166 °F to -4 °F)

-100 °C to 0 °C (-148 °F to +32 °F)

-100 °C to +20 °C (-148 °F to +68 °F)

-80 °C to -20 °C (-112 °F to -4 °F)

-80 °C to 0 °C (-112 °F to +32 °F)

-65 °C to +20 °C (-85 °F to +68 °F)

Certification        IECEx, ATEX

Approvals            CE, UKCA

Automatic Calibration     Span check and correction are performed using two buttons on the transmitter body.

Factory Calibration           Supplied with a calibration certificate traceable to National and International Humidity standards.

Accuracy              ± 2 °C (±0.36 °F) dewpoint

Resolution           0.016 mA

Repeatability      Better than ±0.3 °C dewpoint

Operating Temperature -20 °C to +60 °C

Storage Temperature      -20 °C to +70 °C

Response Times Dry to wet: -100 °C to -20 °C (-148 °F to -4 °F)

- Instantaneous; in less than 5 seconds

Wet to dry: 0 °C to -60 °C (14 °F to -76 °F)

- less than 120 seconds

Sample Flow Rate             Flow independent, ideally 2 - 5 L/m. Max: 20 L/min

Temperature Coefficient Temperature compensated

Calibration Warranty      12 months from date of dispatch

Electrical

Electromagnetic Compatibility (EMC)      Complies with BS EN IEC 61326-1

Warm Up Time  10 seconds

Fault Conditions               Open circuit/under range: output drives to 20.5 mA

Short circuit/over range: output drives to 20.75 mA

Isolation               Sensing element connected to the 4-20 mA loop but isolated from the transmitter body

Output Signal     Linear 4-20 mA with selectable engineering units and fault indication

Operating Voltage            12-28 V DC reverse polarity protected

Maximum Series Resistance         (= {40 x (Supply Voltage – 7)} ohms)

Power Supply     12-28 Vdc Reverse Polarity Protected

Engineering Units             C dewpoint, °F dewpoint, ppm(V), ppb(v), g/m³ and lb/MMSCF

Mechanical

Operating Pressure          From 1 kPa (0.01 bara) to Maximum 35,000 kPa (350 bara)

Operating Humidity (External)    Maximum 95% RH Non-Condensing

Cable Terminations          IP66 / NEMA 4X rated, size C, DIN EN 175301 connector at the Transmitter and other end terminated with bootlace ferrules

Cable     IS (blue) standard cable. Nominal diameter 4.5 mm, 92 ohms/km at +20°C

Enclosure/Body 316 stainless steel

Sensor Protection            316 sintered stainless steel filter – 50 micron

Probe Material (Wetted Parts)    316 stainless steel

Weatherproof Classification         IP66 / NEMA 4X when Connector coupled to Transmitter

Mechanical Connection ¾” UNF (16 TPI) with integral Viton “O” ring seal

Mechanical Warranty     12 months in case of defective parts or faulty workmanship

Dimensions (mm)            180 (H) x 30 (W) x 30 (D) (Short sensor guard)

Weight  234g