ProSoft Technology inRAx 3170-PDP, Руководство пользователя

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Glossary 3170-PDP ♦ FLEX Platform
FLEX I/O™ PROFIBUS Adapter
ProSoft Technology, Inc. Page 135 of 152
August 23, 2007
LED
Light-emitting diode.
link layer
defines a hybrid method for accessing the communication medium (bus) with
master/active stations or slave/passive stations.
Local Station Manager
Rockwell Automation PC program that runs under Microsoft Windows version
3.1. This program transfers data (FDL,CRL, OD, station address, communication
rate, and maximum station address) between the PC and the coprocessor over
RS-232.
logical module
DP protocol describes I/O data exchanged between a PLC master and a slave
device as a set of logical modules (up to 64, but 32 preferred) each one featuring
up to 16 bits maximum of inputs, outputs or a combination of both. The actual
structure of exchanged input and output frames is deduced from this description.
lower layer interface (LLI)
in FMS, responsible for interfacing the FMS layer 7 with FDL layer 2. LLI
manages connections
LSAP or SAP
Link layer Service Access Point. A logical sub-addresses within devices that
allow the distribution of communication flow over dedicated tasks, depending on
the required processing. FMS uses LSAPs indifferently to define generic
communication relationships between two devices (logical communication
channels). DP uses predefined LSAPs to access specific functions or services
between masters and slaves.
master
initiates transfer of messages without any prior remote request. The right to
access the bus (token) is circulated among the master stations. Management of
this logical token ring is performed automatically by the masters (such as startup,
removal or insertion of masters). Also referred to as
active stations or scanner
.
module
any of the plug-in hardware devices that are located in the 1771 I/O chassis:
processor, coprocessor, power supply or I/O module
module slot
location in the I/O chassis for installing a module. Each module slides into a
module slot that lines up with the backplane connector. Also referred to as
slot
.