KONGSBERG GT300 pressure transmitter

3.2 Pressure and Electrical Interface

Pressure interface: The pressure connection located at the lower end of the transmitter complies with the ISO228 standard and mainly provides two specifications of cylindrical threads, G1/2A and G1/4A. These threads are usually sealed with sealing gaskets (such as Viton seals provided with the goods).

Electrical interface: The upper end adopts a connector that complies with DIN 175301-803 standard. This type of connector is commonly known as the "Hirschman connector" or "square plug" in the industrial field, with convenient and reliable wiring. Users can choose the appropriate cable gland based on the outer diameter of the cable, such as M16 or M20 specifications.

Chapter 4: Electrical Characteristics and Installation Specifications

4.1 Power Supply and Load Capacity

The electrical design of GT300 follows the principle of two-wire circuit power supply. The load resistance capability depends on the magnitude of the supply voltage. As shown in Figure 1 (original Fig.1 in the manual), the allowable load resistance is proportional to the power supply voltage. For example, when powered by 24V, it can drive loads up to about 600 Ω (excluding the minimum operating voltage of the transmitter itself), making it easy to work with PLC analog input modules or digital display instruments.

4.2 Wiring Details

When wiring, attention must be paid to polarity and shielding layer handling:

Terminal definition: Terminal 1 is connected to the positive pole (+) of the power supply, and terminal 2 is connected to the negative pole (-) of the signal output.

Cable requirements: Copper screened cable with shielding layer must be used, and the cable cross-sectional area is recommended to be no less than 2 x 0.5 mm ².

Grounding principle: In order to prevent electromagnetic interference (EMI) from affecting the measurement signal, the shielding layer must be single ended grounded on the monitoring system side (i.e. PLC or control cabinet side).

4.3 Fault safety logic

GT300 has a fault self diagnosis function. When there is a malfunction inside the sensor (such as component damage or disconnection), the output current will drop below 3.6mA or rise above 22mA. This "transmitter fault current" mechanism helps the control system identify sensor abnormalities and avoid misoperations caused by incorrect readings.

Chapter 5: Installation Practice and Precautions

Although the GT300 is designed to be sturdy and durable, proper installation is a prerequisite for unleashing its performance.

5.1 Installation direction

The manufacturer recommends installing vertically. This is not only beneficial for mechanical stability, but also reduces zero offset caused by the self weight of the membrane or the deposition of small particles in the medium.

5.2 Installation method

Direct installation: It can be welded directly onto the base of the measuring point through bolts.

Remote installation: Introduce pressure into the transmitter through a pressure conduit. For steam or high-temperature media, the pressure pipe can also play a role in heat dissipation and buffering, preventing high temperatures from directly impacting the sensor electronic unit.

5.3 Environmental Requirements

Despite having IP56 protection, the electronic part of the sensor should be avoided from being exposed to severe thermal radiation or strong electromagnetic interference sources during long-term use. If the temperature of the measured medium changes dramatically, damping or buffering devices can be added within the allowable range of the process.

Chapter 6: Selection Guide and Order Code Interpretation

Understanding the ordering code of GT300 is crucial for proper procurement. According to the "Ordering key" on page four of the manual, we can deconstruct it as follows:

Model example: GT300 C 0 0 C G 1 0 G 0 E05 XXX

GT300: Basic series number.

Pressure Connection:

V=G1/2A, AISI 316L material, Viton seal.

B=G1/4A, AISI 316L material, Viton seal.

OUTPUT SIGNAL:

0 = 4-20mA， Second line system.

Application:

0=General/engine compartment.

Accuracy:

C=0.5% accuracy, temperature compensation range 0-60 ° C.

ZERO POINT:

G=4mA corresponds to atmospheric pressure (zero point of gauge pressure).

K=4mA corresponds to -1 bar gauge (for vacuum or negative pressure measurement).

RANGE AND OVERLOAD PRESSURE:

This is a combination code, for example, 10 corresponds to a range of 0-10 bar and overload of 20 bar; 60 corresponds to a range of 0-60bar, overload of 100bar, etc.

CABLE GLAND:

1=M16 (applicable for cable diameters of 3.5-8mm)

2=M16 * (applicable cable diameter 6-10mm)

3=M20 (applicable cable diameter 7-13mm)

CABLE (cable option):

E05=with 5-meter cable (EFTE oil resistant material)

E10=with 10 meter cable

XXX=Special Customization

Chapter 7: Performance Comparison and Industry Development Trends

7.1 Ceramic Sensor vs. Diffuse Silicon Sensor

In the field of industrial pressure measurement, diffusion silicon sensors and ceramic sensors are the two mainstream technologies. The diffusion silicon sensor has extremely high sensitivity and is suitable for micro pressure measurement, but its PN junction is easily affected in high temperature environments and must rely on a filling liquid isolation medium. Although ceramic sensors (such as those used in GT300) have slightly lower sensitivity than silicon, their characteristics of no hysteresis, overload resistance, and corrosion resistance make them have a longer service life and stability under harsh working conditions. The 0.5% accuracy of GT300 is considered excellent in the general industrial field, while its long-term drift is controlled at an extremely low level through digital compensation.