Senseca

HD402 Pressure Transmitter

Relative and differential pressure transmitter and relay switch for air and dry gases.

Ranges from ±50 Pa up to ±200 kPa, with a temperature-compensated piezoresistive sensor
Output by model: 0…10 V, 0/4…20 mA, 2-wire 4…20 mA, RS485 Modbus-RTU or SPDT relay
Optional 4-digit LCD, IP65 ABS housing and installation in any position

Quantity

Overview

The Senseca HD402 series consists of pressure transmitters and pressure ON/OFF relay switches for relative pressure (to atmosphere) or differential pressure measurement in air and non-aggressive dry gases. Depending on the model, it covers ranges from 50 Pa up to 200 kPa and uses a high-stability silicon piezoresistive sensor with temperature compensation for excellent linearity, repeatability and long-term stability.

The series is factory-calibrated and ready to use, and is available with several output types: 0…10 V and 0/4…20 mA active, 2-wire 4…20 mA, RS485 Modbus-RTU, or an ON/OFF relay switch with SPDT contact. A 4-digit LCD is optional for local reading, and the relay switch versions always include the display, a front red LED and an internal buzzer. The IP65 ABS housing is insensitive to mounting orientation and can be wall-mounted in any position.

Typical applications

HVAC pressure monitoring
Clean air applications
Dry gas applications
Industrial environments (wall mounting)

Key Features

Relative (to atmosphere) or differential pressure measurement
Ranges from ±50 Pa up to ±200 kPa, depending on the model
Piezoresistive sensor with temperature compensation
Output by model: 0…10 V, 0/4…20 mA, 2-wire 4…20 mA, RS485 Modbus-RTU or SPDT relay
Optional 4-digit LCD (always included on relay versions)
Relay versions with front red LED and internal buzzer for alarm signalling
Configuration by PC connection, dip switches or internal buttons (relay models)
Auto-zero on the low-range relay model HD402TR1L

Benefits

Stable readings over time, thanks to the temperature-compensated sensor and long-term stability specifications
The output can be matched to your controller, PLC or BMS, from analog to Modbus-RTU or relay
Factory-calibrated and ready to use, with quick configuration by PC or dip switches
Insensitive to mounting orientation, so it can be installed in any position

Specifications

MEASUREMENT
Sensor	Piezoresistive, high stability
Measuring range	±50 Pa up to ±200 kPa, depending on the model (see Measuring ranges)
Resolution	See Measuring ranges
Response time	0.5 s for the display updating. Configurable 0.125, 1, 2 or 4 s for analog and RS485 output
Zero calibration	Automatic for HD402TR1L, manual for the other models

ACCURACY
Accuracy basis	FSS = nominal range (= 2 x f.s. high range)
HD402TR1	±(0.8% measure + 0.5 Pa) @ 0…50°C
HD402xT1	±1.5% FSS @ 25°C / ±3% FSS @ 0…50°C
HD402xx2	±0.75% FSS @ 25°C / ±1% FSS @ 0…50°C
HD402xx3/4/5	±1% FSS @ 0…50°C
Long-term stability, HD402TR1 (1000 h @ 25°C)	±0.2 Pa with auto-zero
Long-term stability, HD402xT1 / HD402xx2	±0.5% FSS
Long-term stability, HD402xx3	±0.35% FSS
Long-term stability, HD402xx4/5	±0.25% FSS
Overpressure limit, HD402xx1/2/3	50 kPa
Overpressure limit, HD402xx4	200 kPa
Overpressure limit, HD402xx5	400 kPa

MEASURING RANGES
HD402...1	±50 / 100 / 250 Pa, resolution 0.1 Pa
HD402...2	±250 / 500 / 1000 Pa, resolution 1 Pa
HD402...3	±2.5 / 5 / 10 kPa, resolution 0.01 kPa
HD402...4	±25 / 50 / 100 kPa, resolution 0.1 kPa
HD402...5	±50 / 100 / 200 kPa, resolution 0.1 kPa
Other units	For the corresponding measuring ranges and resolution in mmH₂O, inchH₂O and mbar, refer to the manual

OUTPUT
HD402T…	0…10 Vdc or active 0/4…20 mA
HD402AT…	2-wire 4…20 mA
HD402ST…	RS485 Modbus-RTU
HD402TR…	ON/OFF relay switch with SPDT contact
Alarm (HD402TR only)	Front red LED and internal buzzer
Analog output models	Selectable full scale (high / intermediate / low range) and unipolar (0…+f.s.) or bipolar (-f.s…+f.s.) output scaling
Connection to PC	Modbus model: RS485 serial port, connection to a USB port using an RS485 adapter. All other models: RS232 serial port, connection to a USB port using the CP27 cable

POWER REQUIREMENT
HD402T…	24 Vac ±10% or 18…40 Vdc
HD402AT… and HD402ST…	12…30 Vdc
HD402TR…	24 Vac ±10% or 15…36 Vdc
Absorption	<1 W @ 24 Vdc (HD402T…, HD402AT…, HD402TR…)
Electrical connections	Screw terminal block, max 1.5 mm², PG9 cable gland

ENVIRONMENTAL
Operating conditions	-10…+60°C / 0…95 %RH
Storage temperature	-20…+70°C
Compatible media	Only air and non-aggressive dry gases
Protection degree	IP65

MECHANICAL
Materials	Housing: ABS. Pressure connections: nickel-plated brass
Pressure connections	Ø 6 mm
Dimensions	See drawing
Mounting	Two Ø 3 mm rear holes, any installation position

ORDERING CODES
Code structure	HD402 + measuring range (1…5) + type of output (T, AT, ST, TR) + display (blank or L)
Display	Blank = without LCD (except HD402TR…). L = with LCD
Measuring range 1	±250 Pa / 25 mmH₂O / 1 inchH₂O / 2.5 mbar
Measuring range 2	±1000 Pa / 100 mmH₂O / 4 inchH₂O / 10 mbar
Measuring range 3	±10 kPa / 50 mmHg / 1.5 PSI / 100 mbar
Measuring range 4	±100 kPa / 500 mmHg / 15 PSI / 1000 mbar
Measuring range 5	±200 kPa / 1000 mmHg / 30 PSI / 2000 mbar
Type of output	T = 0…10 V and 0/4…20 mA active analog output. AT = 2-wire 4…20 mA analog output. ST = RS485 Modbus-RTU digital output. TR = ON/OFF relay switch output
Supplied with	2 m of silicone tubing (Ø 5 mm internal / Ø 8 mm external) and two plastic fittings for ducts
Ordered separately	PC connecting cable