March 2019 - Professional Partner for Measure & ControlProfessional Partner for Measure & Control

The SMT3151DP Smart Differential Pressure Transmitter utilizes a single-crystal silicon sensor with German MEMS technology, offering higher measurement accuracy. It outputs standard signals (e.g., 4-20mA, 0-5V) and can also be configured with RS485 Modbus RTU or HART protocols.

The single-crystal silicon sensor core features a dual-beam suspension design, significantly improving accuracy and resistance to unilateral and bilateral overload. A built-in intelligent signal processing module achieves perfect integration of static pressure and temperature compensation. This enhances measurement accuracy and long-term stability across a wide range of static pressure and temperature variations.

Sino-Inst offers a variety of smart differential pressure sensors for industrial pressure measurement. If you have any questions, please contact our sales engineers.

More DP Transmitters

Features
Specifications
Datasheet
Order Guide

Features

Blue and white custom housing smart differential pressure transmitter

Output signal 4-20mA output+RS485/HART communication;
0.075%FS high accuracy, millisecond-level ultra-fast response;
Built-in three-button quick operation for on-site adjustment;
Self-diagnosis capability;
Range coverage is 0-0.1KPa~41.0MPa;
Good stability, high precision, adjustable damping, strong resistance to one-way overload.
Explosion-proof housing structure.
LCD display;
IP67 protection rating;
Intelligent static pressure compensation and temperature compensation protect the transmitter from the effects of temperature, static pressure, and overpressure, controlling the overall measurement error at the site within the specified parameters;
High static pressure resistance, up to 40MPa;

Extended reading: How to calibrate HART pressure transmitters

Technical Specifications

Measurement Range	1KPa, 4KPa, 40KPa, 100KPa, 400KPa, 4MPa, 40MPa
Single-Side Overpressure	16MPa
Dual-Side Static Pressure	16MPa 25MPa 40MPa
Measurement Accuracy	±0.075%, ±0.1%, ±0.5% (including linearity, hysteresis, and repeatability from zero)
Measured Medium	Gas, Liquid, Steam
Output Signal	4~20mA DC+RS485/HART protocol
Power Supply	General 10.5~45VDC, intrinsically safe explosion-proof 10.5-26VDC
Power Line Spacing	15cm and above (avoid parallel wiring)
Saturation Current	Upper limit 20.8mA, lower limit 3.8mA
Alarm Current	Upper limit 22.8mA, lower limit 3.6mA (mode adjustable)
Adjustment Function	Zero and full-scale points can be adjusted locally via the three buttons on the top of the casing or remotely via configuration software
Zero Shift	Can be shifted within the range of -20% to +20% of the maximum range
Output Method	Linear output Square root output (can be remotely adjusted via configuration software)
Operating Temperature	-40~85℃
Measured Medium Temperature:	-40℃~120℃ (High temperature customizable)
Diaphragm Material	316L stainless steel/Hastelloy alloy/Tantalum diaphragm/Gold-plated diaphragm
Position Effect	Approximately 200Pa between horizontal and vertical positions
Response Time	10ms
Static Pressure Effect	< 0.05%FS/10MPa
Overpressure Effect	< 0.05%FS/10MPa
Stability	≤0.03%FS/year
Power Supply Effect	< 0.005%FS/V
Explosion-Proof Rating:	Exd Ⅱ CT6 Gb, Exia Ⅱ CT6 Ga
Enclosure Protection Rating:	IP67

SMART Differential Pressure Transmitter Datasheet

SM3151DP-Differential-Pressure-Transmitter Download

Order Guide

Use object: liquid, gas, or steam

Model	Transmitter type
DP	Pressure transmitter
HP	Absolute pressure transmitter
Code	Scale range
2	0-0.10～3.5kPa(0-10～350mmH2O)
3	0-0.8～8.0kPa(0-80～800mmH2O)
4	0-4.0～40kPa(0-400～4000mmH2O)
5	0-20～200kPa(0-2000～20000mmH2O)
6	0-70～700kPa(0-0.7～7kgf/cm2)
7	0-210～2100kPa(0-2.1～21kgf/cm2)
8	0-700～7000kPa(0-7.0～70kgf/cm2)
9	0-2.1～21MPa(0-21～210kgf/cm2)
0	0-4.1～41MPa(0-41～4100kgf/cm2)
Code	Output form
E	Linear output 4-20mAdc
SF	Linear/square root output 4-20mAdc +HART signal,，Full function buttons on site
F	MODBUS-485 signal

Structural materials	Flange connector	Exhaust/Drain valve	Isolation diaphragm	Filling liquid
22	316 Stainless steel	316 Stainless steel	316 Stainless steel	Silicone oil
23	316 Stainless steel	316 Stainless steel	Hastelloy C	Silicone oil
24	316 Stainless steel	316 Stainless steel	Monel	Silicone oil
25	316 Stainless steel	316 Stainless steel	Tantalum	Silicone oil
33	Hastelloy C	Hastelloy C	Hastelloy C	Silicone oil
35	Hastelloy C	Hastelloy C	Tantalum	Silicone oil
44	Monel	Monel	Monel	Silicone oil
Code	Shell material	Conduit inlet dimensions
A	Low copper aluminum alloy polyurethane coating	M20×1.5
B	Low copper aluminum alloy polyurethane coating	1/2-14 NPT
C	Stainless steel	M20×1.5
D	Stainless steel	1/2-14 NPT

Code	Pressure connection
L1	1/4NPT-18 Internal thread（excluding waist joint standard）
L2	1/2NPT-14 Internal thread
L3	M20×1.5 External thread
Code	Optional parts
M4	LCD multi – power digital display head
B1	Pipe bending bracket
B2	Plate bending bracket
B3	Pipe mounting bracket
C02	M20×1.5 nut and Φ 14 pressure short tube
C12	1/2NPT-14 external thread and Φ14 pressure short tube
C22	1/4NPT-18 external thread and Φ14 pressure short tube
C32	1/4NPT-18 to M20×1.5 external thread
C42	1/2NPT-14 to M20×1.5 external thread
C43	1/2NPT-14 to 1/4NPT-18 internal thread
C44	1/2NPT-14 to 1/2NPT-14 external thread
C45	1/2NPT-14 to G1/2 external thread
D1	The side discharge valve is on the upper part
D2	The side discharge valve is on the upper part
X1	Oil ban
Da	Flameproof ExdIIBT5Gb;(explosion-proof certificate no. : CE16.1163)
Fa	Intrinsically safe ExiaIICT4/T5/T6Ga;(explosion-proof certificate no. : CE15.2354X)

Working principle of SMART differential pressure transmitter

The intelligent differential pressure transmitter uses a single-crystal silicon piezoresistive sensor as its core component. When pressure is applied to the sensor, the resistance of the single-crystal silicon changes, which is converted into an electrical signal by the circuit, and then digitally processed to output a standard signal (such as 4-20mA or a digital signal).

Its intelligent feature lies in its built-in microprocessor, which can perform temperature compensation, linear correction, and fault diagnosis, ensuring high measurement accuracy and stability.

The SMT3151DP intelligent differential pressure transmitter integrates differential pressure measurement, display, and signal output functions. This intelligent differential pressure transmitter is used to measure the level, density, flow rate, and pressure of liquids, gases, or vapors.

Smart Differential Pressure Transmitter Applications

SMT3151DP smart differential pressure transmitter is suitable for applications like:

Flow measurement;
- The differential pressure transmitter is combined with the throttling device (like the orifice plate). To convert the flow rate according to the differential pressure value, generated before and after the throttling device.
Level monitoring;
- Measuring the height of the liquid by the pressure difference, generated by the gravity of the liquid itself.
Steam measurement;
Filter or pump differential pressure;
For Monitoring Hydronic HVAC Systems.
Critical process monitoring.

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Generally used in liquid, gas or steam differential pressure, flow measurement. The medium temperature is not too high, corrosion is not strong, viscosity is not high, not easy to crystallize and other environments.

If the working static pressure exceeds 16MPa, a high static differential pressure transmitter should be selected.

FAQ

Help Center

Smart transmitters work on the function of microprocessors for signal transmission.

Smart pressure transmitter consists of two parts: smart sensor and smart electronic board.

The intelligent sensor part includes: capacitive sensor, measuring diaphragm detection circuit, temperature sensor and temperature compensation circuit.

The part of the intelligent electronic board includes: a microcomputer controller and peripheral circuits. It completes the conversion of the pressure signal to 4-20mA dc.

Extended Reading: Digital Pressure Sensor-RS485

Depending on the type of pressure to be measured:

Pressure transmitter types include gauge pressure, absolute pressure, and differential pressure. Gauge pressure refers to the pressure that is less than or greater than atmospheric pressure based on the atmosphere. Absolute pressure refers to the absolute zero pressure as the reference and is higher than the absolute pressure. Differential pressure refers to the difference between two pressures.

According to the working principle of the pressure transmitter:

Strain Gauge Pressure Transducers
Capacitance Pressure Transducers
Potentiometric Pressure Transducers
Resonant Wire Pressure Transducers

Extended reading: Silicon Pressure Sensor

Simply put, a differential pressure transmitter is a device that measures two opposing pressures in a pipe or vessel. Differential Pressure (DP) transmitters measure the difference between two pressures. They use a reference point called the low-side pressure and compare it to the high-side pressure. Ports in the instrument are marked high-side and low-side. The DP reading can be either negative or positive depending on whether the low-side or high-side is the larger value. A DP transmitter can be used as a gauge pressure transmitter if the low-side is left open to the atmosphere.

Extended reading: Featured Diaphragm Seal Pressure Transmitters

The most common and useful industrial pressure measuring instrument is the differential pressure transmitter. This equipment will sense the difference in pressure between two ports and produce an output signal with reference to a calibrated pressure range.

The differential pressure transmitter can be used in combination with other accessories and can be used to measure liquid level and flow.

Differential pressure transmitters and pressure transmitters have many similarities. It can be mixed and used most of the time. As long as it is within the range of the differential pressure transmitter, it can measure not only positive pressure but also negative pressure. When measuring positive pressure, the negative port is open to atmosphere, and when measuring negative pressure, the positive port is open to atmosphere.

Differential pressure transmitters can also measure flow, pipeline pressure difference, tank liquid level, bubble water level, dust, or medium that is easy to crystallize and viscous and fluidity is not good.