HK Instruments RHT Series Installation Instructions

INTRODUCTION

Thank you for choosing an HK Instruments RHT series relative hu-
midity transmitter. The RHT series is intended for use in commercial
environments in HVAC/R applications.
The RHT series measures relative humidity (rH) and temperature (T).
Each measurement parameter (rH, T) has a separate field configur-
able output.
The RHT series relative humidity transmitters are available with
Modbus configuration, relay and touchscreen display.

APPLICATIONS

RHT series devices are commonly used to monitor:
• humidity and temperature levels in offices, public spaces, hospitals,
meeting rooms and classrooms

SPECIFICATIONS

• humidity and temperature in various commercial applications
• humidity and temperature in HVAC/R environment
SPECIFICATIONS
Performance
Measurement ranges:
Temperature: 0...50 °C
Relative humidity: 0–100 %
Accuracy:
Temperature: <0.5 ºC
Relative humidity: ±2...3 % at 0...50 °C and 10–90 % rH
Total error band includes accuracy, hysteresis and
temperature effect over 5...50 °C and 10–90% rH.
Technical Specifications
Media compatibility:
Dry air or non-aggressive gases
Measuring units:
°C and % rH
Measuring element:
Temperature: Integrated
Relative humidity: Thermoset polymer capacitive
sensing element
Environment:
Operating temperature: 0...50 °C
Storage temperature: -20...70 °C
Humidity: 0 to 95 % rH, non condensing
Copyright HK Instruments 2021
HUMIDITY TRANSMITTERS
RHT Series
• READ THESE INSTRUCTIONS CAREFULLY BEFORE
• Failure to observe safety information and comply with
• To avoid electrical shock or damage to equipment, disconnect
• To avoid potential fire and/or explosion do not use in potentially
• Retain these instructions for future reference.
• This product, when installed, will be part of an engineered
Physical
Dimensions:
Case: 99 x 90 x 32 mm
Weight:
150 g
Mounting:
3 screw holes slotted, 3.8 mm
Materials:
Case: ABS
Protection standard:
IP20
Display (Optional)
Touchscreen
Size: 77.4 x 52.4 mm
Electrical connections:
Power supply:
5-screw terminal block
(24 V, GND, rH, T, Max value)
0.2–1.5 mm (12–24 AWG)
2
Relay out:
3-screw terminal block
(NC, COM, NO)
0.2–1.5 mm (12–24 AWG)
2
www.hkinstruments.fi
WARNING
ATTEMPTING TO INSTALL, OPERATE OR SERVICE THIS
DEVICE.
instructions can result in PERSONAL INJURY, DEATH AND/OR
PROPERTY DAMAGE.
power before installing or servicing and use only wiring with
insulation rated for full device operating voltage.
flammable or explosive atmospheres.
system whose specifications and performance characteristics
are not designed or controlled by HK Instruments. Review
applications and national and local codes to assure that the
Installation will be functional and safe. Use only experienced and
knowledgeable technicians to install this device.
Electrical
Input: 24 VAC or VDC, ±10 %
Current consumption: max 90 mA (at 24 V) +
10 mA for each voltage output or 20 mA for each
current output
Temperature output signal:
0–10 V, R>1 kΩ
2–10 V, R>1 kΩ
4–20 mA, R<500 Ω
Relative humidity output signal:
0–10 V, R>1 kΩ
2–10 V, R>1 kΩ
4–20 mA, R<500 Ω
Relay out:
SPDT Relay, 250 VAC / 30 VDC / 6 A
Adjustable switching point and hysteresis
Conformance
Meets requirements for CE marking:
EMC Directive 2014/30/EU
RoHS Directive 2011/65/EU
LVD Directive 2014/35/EU
WEEE Directive 2012/19/EU
COMPANY WITH
MANAGEMENT SYSTEM
CERTIFIED BY DNV GL
= ISO 9001 = ISO 14001 =
INSTALLATION
INSTRUCTIONS
(optional voltage output, display required)
(optional voltage output, display required)
RoHS 2
2011/65/EU
Installation version 7.0 2021