Telaire RH, RHT Specifications

RH/RHT Series

Amphenol

®

Relative Humidity and
Temperature Transmitters

The Relative Humidity (RH) and Temperature
transmitters are designed for continuous
monitoring of relative humidity (RH) or relative
humidity and temperature (RHT). They provide
accurate and reliable measurement for building
automation and environmental control systems.
The units feature very low profile sensor
enclosures that are virtually unnoticeable in most
installations.

The RH and RHT transmitters are available
with ±2%, ±3%, and ±5% RH accuracy (20%
to 95% RH). For monitoring and controlling in
critical environments, the units can be precision
calibrated to 1% accuracy within a specified RH
range.

The RH and RHT transmitters provide a linear
output of 4-20 mA corresponding to 0 to 100%RH.
The RHT transmitter also provides a 4-20 mA
signal corresponding to any of the selected
standard temperature ranges specified.

Features

• Space, Duct, and Outside Air Configurations

• Durable Industrial Enclosures

• Low Profile

• Compact

• Replaceable, Plug-in Bulk Polymer Resistance

RH Sensor

• Resistant to Contamination

• Temperature Compensation

Advanced Sensors

Sensor Enclosure

The relative humidity and temperature sensors are
housed in heavy duty, compact, locking enclosures.
Enclosures may be removed and painted, which further
helps blend them into any environment.

Sensor

The RH sensor incorporates a bulk polymer resistive
element. The polymer is impervious to most
contaminants and, since it is a bulk resistance device,
surface contamination such as dust will not alter the
accuracy of the readings. Imbedded in the polymer is
an interdigitated grid which senses resistance change
as the polymer absorbs or emits molecules of water.

Transmitter

The electronics are contained in a rugged pressure­cast aluminum weatherproof housing designed
for maximum protection. Continuous temperature
compensation adjusts for temperature-induced change
in the RH sensor output. The compensation provides
high measurement accuracy over the entire operating
range of the instrument.

Mounting Template

Dimensions and Mounting

RH and RHT Duct Mount

Mounting Template

(Side View)

RH and RHT Outside Air Mount

Mounting Template

RH Space Mount

2

Wiring Guidelines

Outputs: Relative Humidity

4·20 mA Current Output

The 4-20 mA transmitters will provide a linear
proportional signal with 4 mA corresponding to 0%
RH and 20 mA to 100% RH. These are loop powered
devices; therefore, only two wires are required.

0-5 Volt Voltage Output

The 0 to 5 volt transmitters provide a linear
proportional output at terminal “O” with 0 volts
equivalent to 0% RH and 5 volts to 100% RH.

The voltage output transmitters can be wired as a
three wire transmitter or as a four wire transmitter to
eliminate the effects of wire length. The output voltage
is with respect to Terminals “N” (power supply return)
and/or “G” (signal ground) which are common at the
transmitter.

Wiring Diagram Current Unit

Output: Temperature (Optional)

The temperature option (if ordered) is a separate circuit
board but mounted in the same housing along with the
relative humidity transmitter.

The 4·20 mA transmitters output is linear and
proportional to the range specified when the
transmitter was ordered. The low range temperature
(4 mA) is marked on the ZERO pot and the high range
temperature (20 mA) is marked on the SPAN pot.
Standard range is - 20° to 140°F (this range is supplied
when no range is specified at time of ordering).

The temperature transmitters are entirely separate
circuits from the RH transmitters. Transmitters are
loop powered devices. Therefore, only two wires are
required. One wire may be common with the RH
transmitter.

Wiring

Wiring for the transmitter should be twisted pair(s)
16·22 AWG approximately 2 turns per inch. In
installations near electric motors or sensitive electronic
equipment, use shielded cable. Wiring should be run
through conduit using the 1/2” EMT compression fitting
supplied on the unit.

Wiring Diagram Voltage Unit

3

RH/RHT Specifications

Humidity

Sensing Element

Resistance change of bulk polymer sensor

Performance

Accuracy at 77°F (25°C)

±2% RH, 20-95% RH
±3% RH,, 20-95% RH
±5% RH, 20 -95% RH
including hysteresis, linearity and repeatability

Mechanical: Case Material

Space: ABS Flame Retardant
Duct: Galvanized Steel
Outside Air: Pressure Cast Aluminum and Galvanized
Steel

Mounting Configurations

Space, Duct, Outside Air

Temperature Effect

Less than 0.06% per °F (0.11% per °C)

Sensor Interchangeability

±3% nominal

Operating Range

RH Sensor: 0%-99%, RH, non·condensing.

-40°F to +170°F (-40°C to +76°C)
Electronics: 0%-95% RH, non.condensing.

-40°F to +130°F (-40°C to +54°C)

Max. Air Velocity

10,000 ft/min

Output Range

2·wire. isolated loop, powered 4-20 mA, 0-100% RH
(standard)

Adjustment

Zero: ±20%. non·interactive
Span: ±10%, non·interactive
Long Term Stability: Less than 1 % drift/year typical

Power

Sensitivity

0.1% RH

Repeatability

0.5% RH

Linearity

See Accuracy

Hysteresis

Less than 1%

Supply Voltage

12-36 VDC

Max Load

W = Supply · 10 VDC

0.02 A

Storage Temperature

-85°F to +158°F (-65°C to +70°C)

4

RH/RHT Specifications

Temperature

Sensing Element

Platinum RTD, 4 wire measurement

Performance

Accuracy at 77°F (25”C)

±0.5°F (±0.3°C)

Temperature Effect

Less than 0.01% per °F (0.02% per°C)

Sensitivity

0.1% RH

Repeatability:

0.1% RH

Linearity

Better than 0.1 %

Hysteresis

Less than 0.01%

Optional

0°F to +150°F (-18°C to +66°C)
0°F to +100°F (-18”C to +38°C)
+32°F to +132°F (0°C to +55°C)
+50°F to +130°F (+7°C to +54°C)

-40°F to + 140°F (-40”C to +60°C)
Custom range

Adjustment

Zero: ±10%. non·interactive
Span: ±10%. non-interactive
Long Term Stability: Less than 1% drift per year, typical

Humidity affects you and your operations. Our local
representative Is ready to help in your application. Call
to discuss the proper selection of a humidity device
from the world’s largest selection.

Specifications are subject to change without notice.

Sensor Interchangeability

±0.5°F (±0.03°C)

Output Ranges

4·20 mA

- 20°F to + 140°F (-29°C to +60°C)

5

Ordering Information

Amphenol

Model RH

Code

T with Temperature
Code Accuracy

2 2%
3 3%
5 5%

Code Output

I 4 - 20 mA Current
V 0-5 Volltage DC
Code Temperature Channel Range (optional)
1 -20°F to 140°F (Standard)
2 0°F to 150°F
3 0°F to 100°F
4 +32°F to +132°F
5 +50°F to +130°F
6 -40°F to +140°F
7 Custom Range
Code Mounting Configuration
S Space
D Duct
O/A Outside Air

Model RH - - - -

Example 1: To specify an RH transmitter. order: RH-2-I-S.
Exomple 2: To specify an RH transmitter with optional temperature
sensor with standard range (-20°F to + 140°F), order: RHT-2-I-S.

Options

Special calibration to ± 1% accuracy (20% RH span in 20%·- 95% RH range)

www.telaire.com

Advanced Sensors

www.amphenol-sensors.com

© 2014 Amphenol Corporation. All Rights Reserved. Specifications are subject to change without notice.

Other company names and product names used in this document are the registered trademarks or

trademarks of their respective owners.

AAS-920-509A-04/2014