05-04-2012, 10:33 AM
The Application of HART Protocol in the Converter of Magnetic Flowmeter
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INTRODUCTION
MAGNETIC flowmeter is a flux instrument that has been
extensive used in domestic market because of its no
contamination. The transducer is the main components in the
magnetic flowmeter. The magnetic flowmeter possesses these
particular merits that are security, high reliability and
convenient maintenance. Now there are abundant application in
all kind of electric liquid measure field in industry. For
example, any measure of corrosive liquid such as acerbity,
alkali, and salt; any medium that could fire or explode and so
on. Yet, the trend of the intelligent of magnetic flowmeter is
being. Some famous instrument companies on board have
invented intelligent magnetic flowmeter basing on spot bus,
implementing the digital, network, aptitude.
Seventh floor: application layer. This layer is HART
repertoire. There are three species instructions, which are
current orders, ordinary orders and special orders.
The current orders are all-purpose, which fit for all
intelligent equipments defined by HART protocol in spite of
coming from any company. For example, reading the message
about the manufactories and the types, the variable and its unit,
the output of the current percentage and so on.
PRINCIPLE AND COMPOSING
A. Measuring
The principle of magnetic flowmeter is magnetic influence
law of Faraday. Electric liquid incises magnetic force line when
it flows in the magnetic field, which produces inductive voltage
E, whose extend is direct ratio to the magnetic induction
intensity B; the length of the conductor in magnetic field L, and
the speed of the conductor v. if B, L, v are vertical each other.
Its expression is written below.
DESIGNING IDEA
The theme is how to realize the intelligent magnetic
flowmeter, and achieve to connect the conversion equipment
with the meatus of HART protocol.
The communication between The handy communication
equipment with HART protocol with the MCU of the
conversion equipment in the intelligent magnetic flowmeter
could be realized by the CMOS chip HT2015.
CONCLUSION
The investigation and development of the intelligent
magnetic flowmeter with spot bus could have special meaning
to improve the correlative technology about magnetic
flowmeter in China. The developmental trend of meter is from
pneumatic meter, simulant meter and simulant/ digital HART
protocol to totally digital communication meter. So we might
think it that the spot bus would obtain more extent application
in meter and control field. HART protocol makes the
manufacturer and customer do not contain benefit from
digitally spot communication, but also hold compatibility with
primary system. The HART protocol would make an important
revolution in meter business.