Optidew Vision Precision Dew-Point Hygrometer

This product has now been replaced by our new Optidew 401 and will be withdrawn from the market on 1st July 2018. Orders will only be accepted for this model up to 30th June 2018.

The Optidew Vision precision dew-point meter is based on the proven, fundamental optical dew-point measurement principle, giving long-term drift-free performance. It offers a wide measurement range from the equivalent of <0.5 to 100% RH at ambient temperature (dew point range: -40 to +90°C (-40 to +194°F), and up to +130°C (+266°F) with high temperature option).

The Optidew is an excellent entry level calibration reference, supplied as standard with a fully traceable in-house calibration or optional UKAS-certified calibration. Its simple operation makes it possible for anyone to use with minimum training. Simply connect the instrument, power it up and measurement will begin automatically.

Product Features

  • Fundamental drift-free dew-point measurement
  • Measurement range: <0.5 to 100% RH from -40 to +90°C ambient
  • ±0.2°Cdp (±0.36°Fdp) accuracy; optional higher accuracy available
  • High temperature sensor option to +130°C (+266°F)
  • Rugged NEMA 12 bench-top housing
  • High pressure sensor option to 25 MPa (250 barg/ 3626 psig)
  • Purpose-designed climatic chamber reference sensor option
Optidew Vision

Technical Specification

Measurement Accuracy* ±0.2°Cdp (±0.36°F)
±0.15°Cdp (±0.27°Fdp) accuracy optional
±0.1°C (±0.18°Fdp) temperature
Measurement Units °C, °F dew point; %RH; °C, °F temperature; g/m3; g/kg; aW; ∆ (t-t dew point)
Response Speed 1°C/sec (1.8°F/sec) plus settling time (dew point dependant)
Power Supply 90 to 264 V AC or 127 to 370 V DC, 47 to 440 Hz, 20 W max. internally fused, 4A quick blow
Dew-Point Sensor
Sensor1 Stage2 StageHigh temperature PEEKClimatic or Aluminum head
Dew-Point Range-30°Cdp @ sensor temp of 20°C
+90°Cdp @ sensor temp of 90°C
-40°Cdp @ sensor temp of 20°C
+90°Cdp @ sensor temp of +90°C
-40°Cdp @ sensor temp of 20°C
+130°Cdp @ sensor temp of 130°C
-10°Cdp @ sensor temp of +20°C
+130°Cdp @ sensor temp of +130 °C
Temperature Range-40 to +90°C
(-40 to +194°F)
-40 to +90°C
(-40 to +194°F)
-40 to +130°C
(-40 to +266°F)
-40 to +130°C
(-40 to +266°F)
%RH Range<2 to 100%<0.5 to 100%<0.5 to 100% 10 to 100%
Min Measured Dew Point @ +20°C (+68°F)-30°C (-22°F)-40°C (-40°F)-40°C (-40°F)-10°C (+14°F)
Mirror Material Options Gold plated copper (standard)
Gold stud
316 stainless steel stud**
Platinum stud**
Sensor Body Material Options Acetal (standard)
High temperature PEEK
316 stainless steel**
Anodized aluminum**
Temperature Measurement 4 wire Pt100, 1/3 DIN class B
Sample Flow 0.1 to 2 Nl/min (0.2 to 4 scfh) (in sampling block)
Maximum Velocity 10 m/sec (32.8 f/sec) direct insertion
30 m/sec (98.4 f/sec) with sintered guard
Pressure Standard unit: 2 Mpa / 20 barg (300 psig) (max)
Ingress Protection: IP66
High Pressure version: 25 Mpa / 250 barg (3626 psig) (max)
Ingress Protection: IP65
Sensor cable Standard cable: PVC insulator material, +70°C (+158°F) max temperature
High temperature cable: Silicone insulator material, +180°C (+356°F) max temperature
Cable Length 2m (6.56'); 50m (164') up to 250m (820') on special request
Remote PRT
Temperature Measurement 4-wire Pt100 1/10 DIN class B
Sensor cable Standard cable: PVC insulator material, +70°C (+158°F) max temperature
High temperature cable: PTFE insulator material, +250°C (+482°F) max temperature
Cable Length 2m (6.56'); 50m (164') maximum up to 250m (820') on special request
Transmitter Electronics
Resolution 0.1 for °C, °F and %RH
0.01 for g/m3 and g/kg
Outputs Analog: 4–20 mA or 0–20 mA over user-settable output, Accuracy: ±0.2°C (±3.6°F); 500 Ω maximum load resistance
Digital: RS232 @ 9600 baud rate
Alarm: Volt free contact, 2 A @ 30 V DC, 0.5 @ 120 V AC
Status LEDs DCC / Alarm Status
Operating Temperature -20 to +50°C (-4 to +122°F) ambient
Environmental conditions Up to 98% RH non-condensing
Enclosure Standing case with carry handle, Panel mounting kit optional
Ingress Protection IP54 (NEMA 2)
Cable Pack Mains, RS232 cable and output connector
Calibration 4-point traceable in-house calibration as standard, UKAS accredited calibrations optional – please consult Michell Instruments
*Measurement accuracy means maximum deviation between instrument under test and corrected reference. To this must be added the uncertainties associated with the calibration system and the environmental conditions during testing and subsequent use
** Recommended for special applications only, consult Michell Instruments before ordering

Related Products

Chilled Mirror Reference Instruments

S8000 Remote S8000 Remote
The S8000 Remote provides accurate measurement of dew-point, temperature and relative humidity and is designed for environmental monitoring.
Optidew Optidew
The Optidew is Michell Instruments high performance industrial chilled mirror hygrometer supplied in a rugged IP66, NEMA4 wall-mount enclosure.
S8000 Integrale S8000 Integrale
Features an integrated sensor head allowing measurement in the range of -60°Cdp to +40°Cdp, combining the measurement sensitivity and ±0.1°C dew point accuracy of the RRS system.
S4000 Remote S4000 Remote
The S4000 RC provides accurate measurement of dew-point, temperature and % RH from -85°C to +80°C dew point. The remote sensor is ideal for environmental monitoring.
S4000 TRS S4000 TRS
The S4000 TRS is Michell Instruments' industry proven chilled mirror reference hygrometer providing accurate measurement of dew point to -100°C.

Calibration Instruments

HG-10 HG10
The HG10 is an automatic temperature and humidity calibration system with a wide humidity generation range.
HG-1 HG1
The HG1 is a low-cost, transportable calibrator for dew-point and relative humidity sensors with built in cooled mirror reference.
OptiCal OptiCal
The OptiCal is a premium transportable calibration solution for humidity sensors with built in cooled mirror reference.
The DCS system is a premium customisable rack-mounted dew-point calibration station with cooled mirror reference.
DG2, DG3, DG4 and VDS3 Dew-Point Generators
A range of dew-point generators offering ease of use and fast response to humidity step changes.
Pressure Swing Dryers Pressure Swing Dryers
A source of very dry compressed air for use as a zero gas in humidity calibration systems, or for general laboratory applications.
HygroCal100 HygroCal100 - Humidity Validator
A complete, compact, portable system for automated validation of relative humidity probes.