Field bus specific terms and abbreviations – Festo Контроллеры двигателя SFC-LAC User Manual

Page 21

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Contents and general instructions

XIX

Festo GDCP−SFC−LACI−DN−EN en 0812NH

Field bus specific terms and abbreviations

Term / abbreviation

Meaning

0x1234 or 1234h

Hexadecimal numbers are marked by a prefixed 0x" or by a suffixed h"

ATTR

ATTRibute number

BCD

Binary coded decimal

Bit strobe

All slaves are scanned by the master with a command. Serves for
transmitting small amounts of data between a master and one or several
slaves, e.g.Ăfor synchronizing input or output data (is not supported by
the SFC−LACI−DN).

CI

Command Interface

CLS

CLasS, object classification

COS/Cyclic

The messages are sent either by the master or by the slave cyclically (at a
fixed time interval), or when there is a change of state. In COS messaging,
a message is generated cyclically" if no status change occurs within a
certain time; for this reason COS and Cyclic are often treated as a single
message type.

EDS

Electronic Data Sheet; contains the specific properties of the slave
(e.g.Ănumber of I/Os, parameters, etc.).

Explicit Messaging

Direct connection. Explicit Messaging constitutes an (acyclic)
point−to−point communications connection with low priority between two
devices, and is typically used for configuration and diagnostic purposes.
Explicit messages contain the address and value of an attribute and a
Service Code that describes how these data are to be treated.

I/O messaging (implicit
messaging)

I/O data transfer I/O Messaging" is used for the exchange of
time−critical data (e.g. process data). An I/O message contains
exclusively data. All information about how the data are to be treated are
stored in the Connection" object that is assigned to this message.

I/O polling

The slaves are interrogated by the master.
The master sends a polling command to a slave; data for the slave are
transmitted together with this. If the slave has on its part any data for the
master, then it sends them to the master. If a slave does not answer a
polling request from a master, then this results in a timeout.

INST

INSTance number

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