Differential pressure transmitter
First, the product introduction
TC-3351/3051 intelligent differential pressure transmitter mainly measures the differential pressure, pressure, liquid level and density of liquid, steam and gas, and then converts it into 4-20mA·DC signal for output. The differential pressure transmitter has DP type (differential pressure type), HP type (high static pressure differential pressure) and DR type (differential pressure). It can communicate with each other through the HART protocol's handheld communicator for setup and monitoring.
HP type is often seen on petrochemical and power plant high-pressure devices. The pressure resistance of this product can reach 32MPa. It is not easy to damage when subjected to single overload pressure. Therefore, it is commonly used in measuring the differential pressure of high-pressure system.
DR type differential pressure transmitter can convert tiny differential pressure signal into 4-20mA·DC signal. The design adopts special bead temperature compensation process, so the performance is stable. It is used to monitor the furnace chamber micro-pressure, once, Ideal for secondary air volume and airflow loss.
Second, the working principle
Capacitive pressure and differential pressure transmitters are mainly composed of chamber-sensitive components that implement pressure/capacitance conversion and convert the capacitor into a two-wire 4-20 mA DC electronic circuit board. (See the figure below)
When the process pressure is applied from both sides (or one side) of the measuring chamber to the isolating diaphragm, it is transferred to the central diaphragm of the chamber through the silicone oil filling solution. The central diaphragm is an edge-tensioned diaphragm. Under the action of pressure, the corresponding displacement (up to about 0.1mm) is generated, which can form a differential capacitance change, and is converted into a two-wire 4-20mA·DC signal output through the adjustment, vibration and amplification of the electronic circuit board. The current is proportional to the magnitude of the process pressure.
Third, the assembly exploded view
Adapted to DP, HP, DP And DR type transmitter
Fourth, technical parameters and performance
1, the output signal: 4-20mA · DC two-wire system;
2, power supply; 12-45V · DC;
3, power supply impact: <0.05%>0.05%>
4, load impact: when the power supply voltage is stable, no load impact;
5. Migration characteristics: the maximum positive migration amount is 500%, and the minimum negative migration amount is 600%;
● The absolute value of the negative migration is not more than one engineering atmospheric pressure;
● The absolute values of the upper and lower limits after migration do not exceed the upper limit of the maximum measurement range;
● Migration of differential pressure flow transmitter will destroy the square root characteristics, so migration cannot be performed;
● Absolute pressure transmitters cannot perform negative migration;
6, damping: usually adjustable between 0.2 ~ 1.67 seconds, when filling the inert liquid or with a remote transmission device, the time constant will increase;
7, start-up time: <2 seconds,="" no="" need="" to="">2>
8, explosion-proof type: explosion-proof ExdIIBT4-6 intrinsically safe type ExiaII CT5;
9, indicator table (%); ammeter, scale length 44.5mm, accuracy ± 2%, liquid crystal display, accuracy ± 0.2%;
10. Vibration effect: ±0.005%/g when vibrating in 200HZ in any direction;
11, installation position: the diaphragm is not installed vertically, can produce less than 0.24KPa;
12, temperature effect: ± 0.2%;
13. Static pressure effect: ±0.5%;
14. Accuracy: ±0.25 grade, ±0.5 grade;
15, weight: 5.4Kg (excluding accessories);
Five, capacitive differential pressure transmitter selection