Application: Model 1151 pressure transmitters are available in
various types and can be used for differential pressure, flow,
gauge pressure, absolute pressure, vacuum, liquid level and density
measurement occasions. Determine the model of the transmitter
according to the ordering information table, specify such as
pressure range, output mode and basic structural material of the
transmitter. In addition, options such as accessories,
certifications, special manufacturing procedures, etc. can be
selected. Working principle: During operation, the isolation
diaphragms and tank filling liquid on the high and low pressure
sides transmit the process pressure to the central tank filling
liquid, and the central tank filling liquid transmits the pressure
to the sensing diaphragm in the center of the delta-chamber sensor.
The sensing diaphragm is a tense elastic element whose displacement
varies with the differential pressure experienced (for GP gauge
pressure transmitters, atmospheric pressure acts as if it were
applied to the low pressure side of the sensing diaphragm). AP
absolute pressure transmitter, the low pressure side always
maintains a reference pressure. The maximum displacement of the
sensing diaphragm is 0.004 inches (0.10 mm), and the displacement
is proportional to the pressure. The capacitive plates on both
sides detect the sensing diaphragm. The capacitance difference
between the sensing diaphragm and the capacitive plate is converted
into the corresponding current, voltage or digital HARTR (High
Speed Addressable Remote Transmitter Data Highway) output signal.
Circuit board module (intelligent type): The transmitter circuit
board module adopts application-specific integrated circuit (ASICS)
and surface packaging technology. After the circuit block receives
the digital signal and correction coefficient from the sensor
membrane head, it corrects and linearizes the signal. The output
part of the circuit board module converts the digital signal into
an analog signal output, and can communicate with the HART
hand-held communicator. Data configuration (intelligent):
Configuration data is stored in permanent EEPROM memory on the
transmitter circuit board. The data of the transmitter can still be
saved when the transmitter is powered off, so the transmitter can
work as soon as it is powered on. D/A conversion and signal
transmission (intelligent type): Process variables are stored as
digital data, which can be accurately corrected and converted into
engineering units, after which the corrected data is converted into
an analog output signal. The HART Communicator can directly access
the digital signal of the sensor without digital/analog conversion
to achieve higher precision. Communication mode (intelligent):
Model 1151 intelligent pressure transmitter adopts HART protocol
communication, which adopts the industrial standard Bell202
frequency shift keying (FSK) technology to superimpose a high
frequency signal on the current output signal to realize remote
communication. This technology used by SEI can communicate and
output at the same time without affecting the consistency of the
loop. Software features: The HART protocol makes it easy for users
to configure, test and set up the 1151 Smart Pressure Transmitter.
