Description
Product introduction:
SH2188 pressure transmitter is a device that converts pressure into a pneumatic or electric signal for control and remote transmission.
It can convert the physical pressure parameters such as gas and liquid felt by the load cell sensor into standard electrical signals (such as 4~20mADC, etc.) to supply the secondary instrument such as indicator alarm, recorder, regulator, etc. for measurement and indication. And process adjustment.
Pressure transmitter is the most commonly used sensor in industrial practice. It is widely used in various industrial self-control environments, involving water conservancy and hydropower, railway transportation, intelligent building, production automation, aerospace, military, petrochemical, oil well, electric power, ship. , machine tools, pipelines and many other industries.
Pressure transmitters are available in both electric and pneumatic versions. The electric unified output signal is a DC signal such as 0 to 10 mA, 4 to 20 mA, or 1 to 5 V. The pneumatic unified output signal is a gas pressure of 20 to 100 Pa.
Pressure transmitters can be divided into force (torque) balance type, capacitive type, inductive type, strain type and frequency type according to different conversion principles. The principle, structure and structure of several pressure (differential pressure) transmitters are briefly introduced below. Knowledge of use, overhaul and verification.
The main function of the pressure transmitter is to transmit the pressure signal to the electronic device, and then the pressure is displayed on the computer. The principle is: the mechanical signal of the pressure of the water pressure is converted into the electrical signal pressure and voltage of the current (4-20 mA) or The current magnitude is linear and generally proportional. Therefore, the voltage or current outputted by the transmitter increases as the pressure increases, thereby obtaining a relationship between pressure and voltage or current. The two pressures of the measured medium of the pressure transmitter are fed into the high and low pressure chambers. The pressure of the low pressure chamber is applied to the diaphragm on both sides of the δ element (ie, the sensitive component) by atmospheric pressure or vacuum, and is transmitted to the two sides of the measuring diaphragm through the spacer and the filling liquid in the component.
The pressure transmitter consists of a capacitor consisting of a measuring diaphragm and electrodes on the insulating sheets on both sides. When the pressures on both sides are inconsistent, the measurement diaphragm is displaced, and the displacement is proportional to the pressure difference, so the capacitance on both sides is not equal, passing through the oscillation and demodulation steps.
Working principle:
The electrical components that the pressure transmitter feels pressure are generally resistance strain gauges, which are sensitive devices that convert the pressure on the device under test into an electrical signal. The most widely used resistance strain gauges are metal resistance strain gauges and semiconductor strain gauges. The metal resistance strain gauge has two kinds of filament strain gauges and metal foil strain gauges. Usually, the strain gauge is tightly bonded to the mechanical strain matrix by a special adhesive. When the stress changes due to the force of the substrate, the strain gauges are also deformed together, so that the resistance of the strain gauge changes, thereby adding The voltage across the resistor changes.
Main performance:
1. It can measure oil, water and paste compatible with 316 stainless steel and 304 stainless steel with a wide range of anti-corrosion ability.
2, high accuracy, high stability, the use of imported original sensors, good linearity, high temperature stability;
3, small size, light weight, installation, commissioning, easy to use;
4, stainless steel fully enclosed shell, waterproof;
5. The pressure sensor directly senses the measured liquid level pressure and is not affected by the foaming and deposition of the medium.
Main feature:
1. The pressure transmitter has the characteristics of reliable operation and stable performance;
2, dedicated V / I integrated circuit, fewer peripheral devices, high reliability, simple and easy to maintain, small size, light weight, installation and commissioning is extremely convenient;
3, aluminum alloy die-casting shell, three-terminal isolation, electrostatic spray protection layer, durable;
4, 4-20mA DC two-wire system signal transmission, strong anti-interference ability, long transmission distance;
5, LED, LCD, pointer three indicator head, the field reading is very convenient. Can be used to measure viscous, crystalline and corrosive media;
6, high accuracy, high stability. In addition to the original imported sensor has been corrected by laser, the comprehensive temperature drift and nonlinearity of the whole machine in the operating temperature range are finely compensated.
Installation Notes:
Read the product sample and instruction manual before installing the pressure transmitter. The pressure interface should not leak during installation to ensure the correct range and wiring. The outer casing of the pressure sensor and transmitter should be grounded. The signal cable should not be mixed with the power cable. Strong electromagnetic interference should be avoided around the sensor and transmitter.
Use correctly:
The following conditions should be considered when using the pressure sensor:
1. Prevent the transmitter from coming into contact with corrosive or overheated media;
2. Prevent dross from depositing in the conduit;
3. When measuring the liquid pressure, the pressure tap should be opened on the side of the process pipe to avoid sedimentation;
4. When measuring the gas pressure, the pressure tap should be opened at the top of the process pipe, and the transmitter should also be installed in the upper part of the process pipe so that the accumulated liquid can be easily injected into the process pipe;
5. The pressure guiding pipe should be installed in a place with small temperature fluctuations;
6. When measuring steam or other high-temperature medium, it is necessary to add a condenser such as a buffer tube (coil), and the operating temperature of the transmitter should not exceed the limit;
7. When freezing occurs in winter, the transmitter installed outside must adopt anti-freezing measures to prevent the liquid in the pressure inlet from expanding due to the volume of ice, leading to damage to the sensor;
8. When measuring the liquid pressure, the installation position of the transmitter should avoid the impact of the liquid (water hammer phenomenon), so as to avoid the sensor over-voltage damage;
9. When wiring, pass the cable through the waterproof connector (accessory) or the winding tube and tighten the sealing nut to prevent rainwater from leaking into the transmitter housing through the cable.
