Product guide

37
Humidity and Dew-Point Instruments
Please note: Michell Instruments adopts a continuous development program which sometimes
necessitates specifi cation changes without notice. Please contact us for latest version.
www.michell.com
HVAC / Environmental Control
WM33 & 52
Relative Humidity and Temperature Transmitter, Wall Mount
The WM Series are wall-mounted units that have the ability
to display and provide an output signal of % RH, dew point
or absolute humidity and temperature. The WM Series offers
excellent measurement accuracy and stability wherever a
wall-mounted sensor is required.
Highlights
• WM33 is designed for low cost HVAC applications
• WM52 has digital technology and is designed for accurate
measurements in a controlled environment
• Easy to re-calibrate to maintain high accuracy
Technical Specifi cations
Performance
Measurement range (RH) 0–100% RH
Measurement range (T) -20 to +80°C (-4 to +176°F)
Accuracy at 23°C (73°F)
Humidity
WM52: <±2% RH (10–90% RH)
WM33: <±3% RH (30–80% RH)
Accuracy at 23°C (73°F)
Temperature
WM52: ±0.2°C (±0.36°F)
WM33: ±0.3°C (±0.54°F)
Stability – RH Sensor ±1% RH/year
Response time – RH Sensor <10 sec typical without fi lter (for 90% of
the step change)
Electrical output/input
Output signal 4–20 mA, 0–1, 0–5, 0–10 V
Supply voltage 14–30 V DC (for 0-5 / 0-10 V output)
5–30 V DC (for 0–1 V & 4-20 mA output)
Operating conditions
Operating temperature
Probe, Housing
Storage
-30 to +85°C (-22 to +185°F)
-40 to +85°C (-40 to +185°F)
PRT
Measurement range Pt100/1000:
-50 to +200°C (-58 to +392°F)
Accuracy Pt100/1000: ±0.15°C
Mechanical specifi cation
Housing material White molded polymer
Weight 82g (2.89oz)
Electrical connections Screw terminals
Alternative outputs
Dew point -40 to +60°C (-40 to +140°F)
Absolute humidity 0–200g/m
3
(0-87.4gr/ft
3
)
Dimensions
Issue No: WM33 & 52_97183_V2_UK_1110
Accessories and Spare Parts
19mm (0.75”) Slotted protection cap white A000001
19mm (0.75”) PVDF fi lter A000014
19mm (0.75”) PVDF fi lter with protection cap white A000016
19mm (0.75”) Mesh fi lter with protection cap black A000021
19mm (0.75”) Arrow stainless steel sintered fi lter
5/10/20 m
A000025/26/27
19mm (0.75”) Foil fi lter 2m with protection cap white A000041
19mm (0.75”) Oleophobic foil fi lter 0.7m with
protection cap white
A000043
19mm (0.75”) Foil fi lter 1.5m with protection cap white A000045
You can check your hygrometer with the Control Kit HKC
which is based on the principle of non-saturated salt
solutions. Refer to technical data sheet CONTROL KIT
HKC