1151 capacitive differential pressure transmitter
First, the product introduction
The differential pressure transmitter is suitable for measuring the pressure, differential pressure, density and liquid level of a gas, liquid or vapor, and then converted to a 4-20 mA DC signal output. The 1151 differential pressure transmitter includes DP type (basic type), HP type (high static pressure) and DR (differential pressure). The above three types of transmitters can be combined with intelligent amplifier boards to form an intelligent differential pressure transmitter that can communicate with each other through a HART-compliant hand-held communicator for setup and monitoring.
DR type differential pressure transmitter can convert tiny differential pressure into 4-20mA·DC signal output. The design uses amplified circuit board and special temperature compensation technology. Therefore, the stable performance is used to detect the micro pressure of the furnace combustion chamber. Ideal for primary and secondary air volume and airflow loss.
DP type is The flow transmitter mainly receives the differential pressure signal transmitted from the throttled original, and is converted into a 4-20 mA·DC signal output proportional to the same flow rate through the “J” type electronic circuit board with the square function.
It uses an electronic switch component to switch the output current to less than 20%, which switches the output differential pressure to linearity, which reduces the instability of the output current of the product at the beginning of operation. However, below 50% of the output current, the conversion sensitivity of the flow transmitter is still above the differential pressure transmitter of the same specification, so its stability is slightly lower than that of the differential pressure transmitter.
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 the two 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 liquid, because the central diaphragm is converted into a two-wire system of 4-20 mA. DC signal output, the output current is proportional to 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 should 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%, 0.5%, 1.0%
15, weight: 5.4Kg (excluding accessories);
Five, capacitive differential pressure transmitter selection