TotalFlow XRC6490, Руководство пользователя

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B-37
TERM DEFINITION
Proportional, Integral,
Derivative PID Controllers are designed to eliminate the need for continuous operator
attention. An example would be the cruise control in a car or a house
thermostat. These controllers are used to automatically adjust some variable to
hold the measurement (or process variable) at the set-point. The set-point is
where you would like the measurement to be. Error is defined as the difference
between set-point and measurement.
Propylene (C3H6) A saturated hydrocarbon (Alkane) gas, the molecule of which is composed of
three carbon and six hydrogen atoms. At room temperature and pressure,
propylene is a gas. It is colorless, highly flammable, and has a odor similar to
garlic. It is found in coal gas and can be synthesized by cracking petroleum.
The main use of propylene is as a monomer, mostly for the production of
polypropylene.
Protocol A formal set of conventions governing the formatting and relative timing of
message exchange between two communicating systems.
PSI Pounds per Square Inch.
PSIA Pounds per Square Inch Absolute. Absolute pressure uses a perfect vacuum as
the zero point. A perfect vacuum is 0 PSIA.
PSIA=PSIG + Atmospheric Pressure.
PSID Pounds per square inch differential. Pressure difference between two points.
PSIG Pounds per Square Inch Gauge. Gauge pressure uses the actual atmospheric
pressure as the zero point.
PSIS Pounds per square inch standard. Pressure referenced to a standard
atmosphere.
PTB Physikalisch Technische Bundesanstalt (Federal Physical Technical Office) or
Technical Institute for Certification.
PTC See Positive Temperature Co-efficient Fuse.
Pulse Input Any digital input to a meter (usually a turbine) that is used to measure pulses
over a time period. This calculates volume and flow rate for each period of time.
Pulse Mode An operational mode used by the LevelMaster for measuring single float levels
by transmitting a pulse to the primary windings, reading the voltage level on
both the primary and secondary windings and using a calculation whereby one
is subtracted from another to determine the single fluid level.
Pulse Output Any digital output that is used to measure pulses over a period of time.
Frequency of Pulses in a predetermined time frame represents a value to be
used in calculating volume and flow rate.
Radio Frequency RF for short. That part of the spectrum from approx. 50kHz to gigahertz.
Radio Frequency
Interference Electromagnetic radiation which is emitted by electrical circuits carrying rapidly
changing signals, as a by-product of their normal operation, and which causes
unwanted signals (interference or noise) to be induced in other circuits.
RAM See Random Access Memory.
RAM Disk A lithium backed storage chip. Also see Random Access Memory.
RAMS Acronym for Remote Alarms Monitoring System.
Random Access Memory Onboard read/write volatile memory, generally used for application variables
and the file system. Data stored is lost if power is removed (volatile).
Range Those values over which a transducer is intended to measure, specified by its
upper and lower limits.
Rangeability The ratio of the maximum flowrate to the minimum flowrate of a meter.
Rated Capacity The number of ampere-hours a cell/battery can deliver under specific
conditions (rate of discharge, cut-off voltage, temperature).
Raw Gas Natural gas that has not been processed.