The AcuDew dewpoint transmitter is fully compatible with the new range of single channel displays: AcuLoop plug in signal indicator for local display; the panel mount AcuVu with 4-20 mA retransmission and fully programmable alarms; and the AcuTrak with additional onboard pressure dewpoint calculations and RS485 communications, as well as the existing SU4 sample system.

SHAW Model AcuDew high performance dewpoint transmitter. A new, robust and reliable, 2 wire, 4-20 mA loop powered transmitter.

Utilising the ultra high capacitance SHAW moisture sensing technology, the AcuDew offers superior sensitivity, accuracy, repeatability and speed of response.

This dewpoint transmitter incorporates the SHAW AutoCal feature, thereby allowing users to check the span of the instrument and correct for any deviation between annual laboratory calibrations. Notably, AutoCal can be carried out in situ and without the need for skilled personnel or special equipment.

Built of a robust stainless-steel construction and an industrial M12 connector. The SHAW dewpoint transmitter can withstand extreme environmental conditions and is suited to harsh environments providing a protection rating of IP66 (NEMA 4X). The M12 connector reduces setup time by saving time installing and maintaining wiring systems.

AcuDew dewpoint transmitter provides a linear, 4 – 20 mA, signal over the chosen measurement range and is loop powered by a 7 – 28 V DC source (24 V option available). When installed in remote locations, the 4 – 20 mA signal can be transmitted to a control system over distances of up to 1,000 metres (3,280 feet).

Easy to operate, the SHAW AcuDew can be installed directly in to the process line or as part of a sample conditioning system and requires little or no maintenance. This new dewpoint transmitter has been tested to withstand pressures up to 35,000kPA (350 bar) and consequently can be directly connected into pipelines. Another key point, when installed correctly, there are no controls to operate during normal use because the AcuDew is designed for long term unattended operation.

Supplied ready to use with a Certificate of Calibration traceable to National and International Humidity Standards, instruction manual and two metres of cable.

Key features of Model AcuDew

• 2 wire, loop powered, 4-20 mA dewpoint transmitter
• Shaw brand accurate held hygrometer
• Various ranges: overall range -120 °C to +20 °C (-148 °F to +68 °F) dewpoint
• Shaw brand accurate held hygrometer
• Accuracy ±2 °C (±3.6 °F) dewpoint
• Shaw brand accurate held hygrometer
• Output configurable in °C dewpoint, °F dewpoint, ppm(v), ppb(v), g/m³ and lb/MMSCF
• AutoCal calibration feature
• Shaw brand accurate held hygrometer
• Open/short circuit detection
• Shaw brand accurate held hygrometer
• Weatherproof rating IP66 (NEMA 4X)
• Shaw brand accurate held hygrometer
• Fully compatible with the single channel displays: Model AcuLoop, Model AcuVu, Model AcuTrak and SU4 Sample System

Various Ranges

Various dewpoint ranges are available covering an overall range from -120 °C to +20 °C (-148 °F to +68 °F) dewpoint and output units are configurable in °C dewpoint, °F dewpoint, ppm(v), ppb(v), g/m³ and lb/MMSCF.

Automatic calibration

The most important and unique feature of the SHAW system is the automatic calibration facility… (read more)

The most important and unique feature of the SHAW system is the automatic calibration facility. Each SHAW Dewpoint Sensor is precisely manufactured to saturate with water vapour at its design maximum. Hence, when the dew point sensor is exposed to moisture above its maximum operating range, it will rapidly come into equilibrium and cease to respond to any further increase in moisture. This forms the basis of automatic calibration (AutoCal).

The SHAW dewpoint sensor can be checked by simply exposing it to any atmosphere which is wetter than the operating range of the dewpoint sensor (usually room air is sufficient) by raising the desiccant chamber and performing the AutoCal feature on the instrument. The dewpoint sensor is now set up with the instrument and ready for use. Automatic calibration of SHAW dewpoint instruments allows user to ensure accuracy between laboratory calibrations by checking the span of the hygrometer instrument and correcting for any deviation.

Automatic calibration can be carried out in-situ and without the need for any special equipment or skilled personnel. The net result is reduced downtime, minimal calibration costs and immediate verification of the dewpoint system. AutoCal can be performed every two to three months but should not replace true calibration against a known standard

To learn more, watch this helpful video