HK Instruments RHT-MOD Duct Series Installation Instructions

INTRODUCTION
Thank you for choosing an HK Instruments RHT-MOD Duct se-
ries relative humidity transmitter with Modbus interface. The RHT
-MOD Duct series is intended for use in commercial environments
in HVAC/R applications.
RHT-MOD Duct is a relative humidity transmitter with temperature
output installed in air ventilation duct. In addition to these measured
values, RHT-MOD Duct calculates various parameters such as dew
point, mixing ratio, enthalpy and absolute humidity. Illuminated dis-
play ensures easy readability also from a distance. The RHT-MOD
Duct has a screwless lid and an easily adjustable mounting flange
that make the installation of the device easy.
APPLICATIONS
RHT-MOD Duct series devices are commonly used to monitor and
control:
• Relative humidity and temperature levels of incoming and return air
SPECIFICATIONS
in ventilation system
SPECIFICATIONS
Performance
Measurement ranges:
Temperature: -30...80 °C, sensor
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: NTC10k
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-MOD Duct 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: 119 x 95.5 x 45 mm
Probe: L=188 mm, d=12 mm
Mounting:
With flange, adjustable 40...155 mm
Weight:
150 g
Materials:
Case: ABS
Cover: PC
Probe: ABS
Mounting flange: LLPDP
Protection standard:
IP54
Electrical connections:
4 spring loaded terminals
Power supply:
(24 V and GND)
0.2–1.5 mm (16–24 AWG)
2
Modbus RTU:
A and B line
0.2–1.5 mm (16–24 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
Supply voltage: 24 VAC or VDC ±10 %
Current consumption: max 90 mA (at 24 V) + 10 mA for
each voltage output
Communication
Protocol: MODBUS over Serial Line
Transmission Mode: RTU
Interface: RS485
Byte format (11 bits) in RTU mode:
Coding System: 8-bit binary
Bits per Byte:
Baud rate: selectable in configuration
Modbus address: 1−247 addresses selectable in
configuration menu
Conformance
Meets the requirements for:
EMC:
RoHS:
WEEE:
INSTALLATION
INSTRUCTIONS
1 start bit
8 data bits, least significant bit sent
first
1 bit for parity
1 stop bit
CE: UKCA:
2014/30/EU S.I. 2016/1091
2011/65/EU S.I. 2012/3032
2012/19/EU S.I. 2013/3113
Installation version 7.0 2021
RoHS
COMPLIANT