Smart Differential Pressure Transmitter

The WH3051 miniaturized series pressure/differential pressure transmitter uses a capacitive sensor core from Dongfang Wanhe Instruments, which is widely used and technologically mature. It features high-precision manufacturing processes and technology, producing this new series of pressure/differential pressure transmitters. The modular design and full surface-mount packaging make the product more sophisticated.

The WH3051 series pressure/differential pressure transmitter offers two specifications to meet the requirements of different domestic users: Type N (analog) and Type S (smart). The smart series allows for on-site zero adjustment or re-calibration of the range via an on-site button, and also allows for passive calibration and data configuration via a hand-held device or communication software. According to user's special needs, the intelligent series can achieve a wide range ratio (100:1) and high accuracy (0.1%).

☆ Increased flexibility and enhanced functionality due to the use of a microprocessor; it has strong self-diagnostic capabilities.
☆ Wide range coverage: 0~0.2kPa~41.37MPa
☆ Accuracy better than 0.1 grade, can reach 0.075 grade, range ratio better than 40:1
☆ Zero point and range adjustments do not affect each other.
☆ Features both remote and local range and zero point adjustment.
☆ With HART protocol
☆ Sensor includes non-volatile memory.
☆ Good stability, high accuracy, adjustable damping, and strong resistance to unidirectional overload.
☆ No mechanical transmission parts, less maintenance work, and robust and anti-vibration.
☆ All general-purpose components; the sensor and electronic board are interchangeable without affecting the transmitter characteristics, making maintenance more convenient.
     

★ Oil/Petrochemical/Chemical
★ Power/City Gas/Others
★ Pulp and Paper
★ Iron and Steel/Non-ferrous Metals/Ceramics
★ Machinery/Shipbuilding

Product Features

• Increased flexibility and enhanced functionality due to the use of a microprocessor;
• Possesses strong self-diagnostic capabilities;
• Wide measurement range coverage0~0.2kPa~41.37MPa；
• Accuracy better than0.1grade, measurement range better than40：1；
• Features both remote and local range and zero-point adjustment;
• Two-wire, compliant withHART^®protocol, can perform digital communication withROSEMOUNT275type andHK-HART375type hand-held devices without interrupting analog output;
• Sensor includes non-volatile memory;
• Good stability, high accuracy, adjustable damping, strong resistance to unidirectional overload;
• No mechanical transmission parts, less maintenance, robust and vibration resistant;

Working Principle

WH3051The transmitter consists of two parts: a sensor and an electronic circuit board. The sensor part includes: sensitive element, direct digital capacitance circuit, temperature sensor and characterizationEEPROMetc.; the electronic circuit board part includes: microprocessor, analog-to-digital/signal converter, digital communication and memoryEEPROMetc., completing the conversion of pressure signals to4~20mAThe above is a simple explanation of its principle:

                            WH3051Principle Diagram

Sensor Part

    Sensitive Element:The medium pressure is transmitted to theδmeasurement diaphragm at the center of the chamber through an isolation diaphragm and filling oil. This measurement diaphragm is a tight elastic element used to detect the differential pressure on the measurement diaphragm. The displacement of the measurement diaphragm is proportional to the differential pressure, with a maximum displacement0.004inch（0.10mm）。The position of the measurement diaphragm is detected by a direct digital capacitance circuit through the capacitive fixed plates on both sides of it.

    Direct Digital Capacitance Circuit:This circuit is used to convert the pressure applied to the sensitive element into a frequency signal, and to make this frequency signal proportional to the pressure signal, forCPUsampling.

    Temperature Sensor:Used to measure the working medium temperature of the pressure sensor and convert it into a digital signal for digital temperature compensation by the microprocessor.

    CharacterizationEEPROM：Stores transmitter temperature compensation, sensor characteristic curves and characteristic data, and digital fine-tuning data, etc. Even if the power is turned off, the data can still be completely stored in the memory.EEPROMTotal Storage Capacity512bytes.

Electronic Circuit Board Part

    HART^®Communication:The digital communication circuit provides an interface between the transmitter andHK-HART375the hand-held device or control system. This circuit detects the superimposed4~20mAloopFSK(Frequency Shift Keying) signal, and the sending part superimposes the signal on the4~20mAloop in the same way.

Technical Performance

Target Application:Liquids, Gases

Output Signal:4~20mAOutput superimposedHART^®protocol digital signal (two-wire)

Power Supply:External power supply24VDC，(Power range12V~45V)

Load Characteristics:The allowable load resistance Rmax of the load resistance loop is (E-12)/0.02(Ω), as shown in the figure

Migration Characteristics:Regardless of the output, after positive and negative migration, the upper and lower limits of its range must not exceed the range limits.

Temperature Range:Medium Temperature -40～104℃

            Storage Temperature -40～85℃

            Overall Operating Temperature -40～85℃

                            -20～70℃ (with digital display)

Relative Humidity:  0～100%

Volume Change:Less than 0.16cm³

Damping:  Time constant adjustable0.2between ～32.0s

Start-up time:  3s, no warm-up required

Pressure connection:  Flange¹/₄-18NPT (tapered pipe thread)

　　　　　　 Connector¹/₂-14NPT (tapered pipe thread)

Electrical connection:  Using¹/₂-14NPT threaded conduit and terminals with matching test piece

Weight:  3.5kg (transmitter body excluding options)

Wiring diagram

Dimensions

Installation connection Size drawing