Rockwell Automation 1757-FFLD Linking Device Configuration Manual - Manual (Page 146)

Publication 1757-PM002A-EN-E - June 2006
Glossary 4
OPC (Object
Linking and
Embedding for
Process Control) Software application which allows bidirectional data flow between two separate
applications. These applications may be running on the same or on separate servers.
Output Parameter A block parameter that sends data to another block.
Physical Layer Receives messages from the Communications Stack and converts the messages into
physical signals on the fieldbus transmission medium, and vice-versa.
PID Proportional Integral Derivative.
Regulatory Control The functions of process measurement, control algorithm execution, and final control
device manipulation that provide closed loop control of a plant process.
Resource Block Describes characteristics of the fieldbus device such as the device name, manufacturer
and serial number. There is only one Resource Block (RB) in a device.
RSFieldbus A graphical environment for creating links, loops, and schedules. You can use
RSFieldbus to configure a fieldbus network and keep track of your configuration
changes.
RSLogix Software that provides a programming environment for sequential, process, drive and
motion control programming. The RSLogix environment provides an IEC61131-3
compliant interface for controls programming.
s Seconds.
Schedules Define when Function Blocks (FBs) execute and when data and status is published on
the bus.
Segment A section of an H1 fieldbus that is terminated in its characteristic impedance.
Segments can be linked by Repeaters to form a longer H1 fieldbus. Each Segment can
include up to 32 H1 devices.
Splice An H1 Spur measuring less than 1 m (3.28 ft.) in length.
Spur An H1 branch line connecting to the Trunk that is a final circuit. A Spur can vary in
length from 1 m (3.28 ft.) to 120 m (394 ft.).
Standard Function
Block (FB) Blocks built into fieldbus devices as needed to achieve the desired control functionality.
Automation functions provided by Standard FBs include Analog Input (AI), Analog
Output (AO) and Proportional/Integral/Derivative (PID) control. The Fieldbus Foundation
has released specifications for 21 types of Standard FBs. There can be many types of
FBs in a device. The order and definition of Standard FB parameters are fixed and
defined by the specifications.
Tag A collection of attributes that specify either a control loop or a process variable, or a
measured input, or a calculated value, or some combination of these, and all associated
control and output algorithms. Each tag is unique.
Tag Id The unique alphanumeric code assigned to inputs, outputs, equipment items, and
control blocks. The Tag Id might include the plant area identifier.
Terminator Impedance-matching module used at or near each end of a transmission line that has
the same characteristic impedance of the line. Terminators are used to minimize signal
distortion, which can cause data errors by converting between current variations and
voltage variations. H1 terminators also convert the current signal transmitted by one
device to a voltage signal that can be received by all devices on the network.
Topology Shape and design of the fieldbus network (for example, tree branch, daisy chain,
point-to-point, bus with spurs, etc.).
Term Definition