HK Instruments DPT-MOD Series Installation Instructions

INTRODUCTION
Thank you for choosing an HK Instruments DPT-MOD series dif-
ferential pressure transmitter. The DPT-MOD differential pressure
transmitter for air conforms to Modbus over serial line protocol,
using RTU transmission mode and RS485 interface. The digital
output signal is sent over Modbus enabling the DPT-MOD to con-
nect directly to a field communications network.
DPT-MOD requires less wiring than traditional 3-wire transmitters,
since multiple devices can be connected on serial line.
The DPT-MOD includes an Input terminal that 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 (poten-
tial free contact) signals. For example, DPT-MOD can read values
from one differential pressure measurement point and two tem-
perature measurement points.
APPLICATIONS
DPT-MOD series devices are commonly used in HVAC/R
systems for:
• fan, blower and filter monitoring
• pressure and flow monitoring
SPECIFICATIONS
• valve and damper control
• pressure monitoring in cleanrooms
SPECIFICATIONS
Performance
Accuracy (from applied pressure):
±1.5 % + 1 Pa
(Including: general accuracy, temperature drift, linearity,
hysteresis, long term stability and repetition error)
Response time:
1...20 s selectable via menu
Max pressure:
400 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 autozero
• Via Modbus write coil
Copyright HK Instruments 2014
DIFFERENTIAL PRESSURE TRANSMITTERS
DPT-MOD Series
• READ THESE INSTRUCTIONS CAREFULLY BEFORE
ATTEMPTING TO INSTALL, OPERATE OR SERVICE THIS
DEVICE.
• Failure to observe safety information and comply with
instructions can result in PERSONAL INJURY, DEATH AND/OR
PROPERTY DAMAGE.
• To avoid electrical shock or damage to equipment, disconnect
power before installing or servicing and use only wiring with
insulation rated for full device operating voltage.
• To avoid potential fire and/or explosion do not use in potentially
flammable or explosive atmospheres.
• Retain these instructions for future reference.
• This product, when installed, will be part of an engineered
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.
Technical Specifications
Media compatibility:
Dry air or non-aggressive gases
Measuring units:
Selectable via menu (Pa, mbar, inchWC, mmWC, psi)
Measuring element:
Piezoresistive
Environment:
Operating temperature: -10...+50 °C
Storage temperature: -20...+70 °C
Humidity: 0 to 95 % rH
Physical
Dimensions:
Case: 102.0 x 71.5 x 36.0 mm
Weight:
150 g, with accessories 290 g
Mounting:
2 each 4.3 mm screw holes, one slotted
Materials:
Case: ABS
Lid: PC
Pressure inlets: Brass
Duct connectors: ABS
Tubing: PVC
Protection standard:
IP54
www.hkinstruments.fi
WARNING
Display:
2-line display (12 characters/line)
Line 1: active measurement
Line 2: units
Electrical Connections:
4+3 spring load terminals, max 1.5 mm
Cable Entry: M20
Pressure fittings:
Male 5,0 mm and 6,3 mm
Electrical
Supply voltage:
24 VAC or VDC ± 10 %
Power consumption:
< 1.3 W
Output signal:
via Modbus
Conformance
Meets requirements for CE marking:
EMC directive 2004/108/EC
RoHS Directive 2002/95/EC
INSTALLATION
INSTRUCTIONS
2
Installation version 2.0 2014