HK Instruments DPT-Dual-MOD-AHU Series Installation Instructions

INTRODUCTION
Thank you for choosing an HK Instruments DPT-Dual-MOD-AHU
series differential pressure transmitter. DPT-Dual-MOD-AHU is es-
pecially designed for air handling units, combining two differential
pressure transmitters into one device. It offers a possibility to meas-
ure pressure from two different points. One of the measurements
can be set to show the air flow rate. DPT-Dual-MOD-AHU has a
Modbus interface and an Input terminal.
The Input terminal enables reading of multiple other signals such as
temperature or control relays over Modbus. The Input terminal has
two input channels designed to accept 0−10 V, NTC10k, Pt1000,
Ni1000/(-LG), and BIN IN (potential free contact) signals.
APPLICATIONS
DPT-Dual-MOD-AHU series devices are commonly used in HVAC/R
systems for:
• air flow monitoring across centrifugal fans and blowers
• in-duct air flow monitoring
• VAV applications
• fan, blower and filter monitoring
• pressure and flow monitoring
• valve and damper control
• pressure monitoring in cleanrooms
SPECIFICATIONS
Performance
Accuracy (from applied pressure):
Sensor A (-700...7000 Pa):
Pressure < 125 Pa = 1.5 % + ±2 Pa
Pressure > 125 Pa = 1.5 % + ±1 Pa
Sensor B (-250...2500 Pa):
Pressure < 125 Pa = 1 % + ±2 Pa
Pressure > 125 Pa = 1 % + ±1 Pa
(Including: general accuracy, linearity, hysteresis, long
term stability and repetition error)
Input accuracy:
<0.5%
Response time:
1...20 s selectable via menu
Overpressure:
Proof pressure: 25 kPa
Burst pressure: 30 kPa
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:
1 start bit
8 data bits, least significant bit sent
first
1 bit for parity
1 stop bit
Baud rate: selectable in configuration
Modbus address: 1−247 addresses selectable in
configuration menu
Zero point calibration options:
• Manual pushbutton
• Via Modbus write coil
Copyright HK Instruments 2023
DIFFERENTIAL PRESSURE TRANSMITTERS
DPT-Dual-MOD-AHU
• 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
Technical Specifications
Media compatibility:
Dry air or non-aggressive gases
Measuring units on display (Selectable via menu):
Pressure: Pa, kPa, mbar, inchWC, mmWC, psi
Flow: m /s, m /hr, cfm, l/s, m/s, ft/min
3 3
Measuring element:
MEMS, no flow-through
Environment:
Operating temperature: -20...50 °C
Temperature compensated range 0...50°C
Storage temperature: -40...70 °C
Humidity: 0 to 95 % rH, non-condensing
Physical
Dimensions:
Case: 102.0 x 71.5 x 36.0 mm
Weight:
150 g
Mounting:
2 each 4.3 mm screw holes, one slotted
Materials:
Case: ABS
Lid: PC
Pressure inlets: Brass
Tubing: Silicone
Protection standard:
IP54
Display:
2-line display (12 characters/line)
Line 1: active measurement, inlet A
Line 2: active measurement, inlet B
If inputs are selected, the lines show also input
information (for example temperature)
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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 Connections:
4+4 spring load terminals, max 1.5 mm
Cable Entry: M20
Pressure fittings:
Male 5.2 mm
+ High pressure
- Low pressure
Electrical
Supply voltage:
24 VAC or VDC ± 10 %
Power consumption:
< 1.3 W
Output signal:
via Modbus
Input signals:
2 x input (0...10 V, NTC10k, Pt1000, NI1000/(-LG), or
BIN IN)
Conformance
Meets requirements for:
EMC:
RoHS:
WEEE:
INSTALLATION
INSTRUCTIONS
2
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 1.0 2023
RoHS
COMPLIANT