TotalFlow XRC6490, Руководство пользователя

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B-34
TERM DEFINITION
Ole for Process Control This is a data interchange format and supporting software. Typically, vendors
(such as ABB) write OPC server drivers which can talk to their devices. SCADA
system vendors (again like ABB) write OPC clients that can gather data from
OPC Servers. The idea is to provide a universal way to collect data into a
SCADA system regardless of the equipment vendor. This standard was
developed and is maintained by the OPC Foundation. The Totalflow Driver,
TDS32, supports OPC.
Ole for Process Control
Database
A programming interface to databases. IVision supports the OLEDB interface.
OLEDB See Ole for Process Control Database.
Olefins Basic chemicals made from oil or natural gas liquids feedstocks; commonly
used to manufacture plastics and gasoline. Examples are ethylene and
propylene.
OOP Object-Oriented Programming. The XFC/XRC architecture incorporates an
object-oriented approach.
OPC See Ole for Process Control.
Open Circuit A complete break in a metal conductor path.
Open Circuit Voltage The difference in potential between the terminals of a cell/battery when the
circuit is open (no-load condition).
Open Collector A single NPN transistor with the base connected to the logic driving circuitry
and with the emitter grounded. The collector is the output pin of the gate.
Open Database
Connectivity A widely accepted application-programming interface (API) for database
access. It is based on the Call-Level Interface (CLI) specifications from X/Open
and ISO/IEC for database APIs and uses Structured Query Language (SQL) as
its database access language. Using ODBC, you can create database
applications with access to any database for which your end-user has an
ODBC driver. This allows access for authorized users to databases over any
network, including the Internet. The iVision SCADA system provides an ODBC
driver, making the database accessible to authorized users anywhere on a
corporate network, or even over the Internet if the network is properly
configured.
Operating System Base-level software that controls a computer, runs programs, interacts with
users, and communicates with installed hardware or peripheral devices.
Optional Equipment Unit Totalflow enclosure designed to house optional power and communication
devices.
Orifice Meter Device to record differential pressure measurement which uses a steel plate
with a calibrated hole or orifice to generate a drop in pressure between the two
sides of the plate. Also the primary element of the meter run.
Orifice Plate A plate of non-corrosive material which can be fastened between flanges or in a
special fitting perpendicular to the axis of flow and having a concentric circular
hole. The primary use is for the measurement of gas flow.
ORing Boolean algebra logical function. Described as the addition or summing of
switches or inputs, in the case of Boolean elements, the 0 and 1 represent two
possible states of a premise or hypothesis: True or False, On or Off. When
adding Boolean elements not real numbers, you will find these results:
1 or 1 = 1
1 or 0 = 1
0 or 1 = 1
0 or 0 = 0
O-Ring A flat ring made of rubber or plastic, used as a gasket.
Output That part of a circuit where the processed signal is available.
Output Impedance The resistance as measured on the output terminals of a pressure transducer.