Distributed I/O System ET 200S

SSI
The transfer of path information takes place synchronously according to the SSI protocol
(Synchronous Serial Interface). The SSI protocol is used with absolute position sensors.
Glossary
SSL (System Status List)
The System Status List SSL describes the current status of the automation system: It gives
an overview of the setup, the current parameter settings, the actual statuses and processes
in the CPU and the assigned modules.
The data of the SSL can only be read and not modified.
Stationary wiring
All the wiring-carrying elements (terminal modules) are mounted on a rail. The power and
electronic modules are plugged onto the terminal modules.
Switch
SYNC
PROFIBUS is a linear network. The communication nodes are connected with one another
by means of a passive line - the bus.
By contrast, the Industrial Ethernet consists of point-to-point connections: each
communication node is directly connected to exactly one communication node.
If a communication node is connected with several communication nodes, this
communication node is connected to the port of an active network component - the switch.
Additional communication nodes (including switches) can now be connected to the other
ports of the switch. The connection between a communication node and the switch remains
a point-to-point connection.
A switch also has the task of regenerating and distributing received signals. The switch
"learns" the Ethernet address(es) of a connected PROFINET device or other switches and
only forwards signals, which are destined for the connected PROFINET device or the
connected switch.
A switch has a specific number of ports. You connect at most one PROFINET device or
additional switch to each port.
This is a control command of the DP master to a group of DP slaves.
With the SYNC control command the DP master prompts the DP slave to freeze the statuses
of the outputs at the value at that moment. With the subsequent frames, the DP slave stores
the output data, but the statuses of the outputs remain unchanged.
After each new SYNC control command, the DP slave sets the outputs that it has stored as
output data. The outputs are not cyclically updated again until the DP master sends the
UNSYNC control command.
Technological modules
Modules which are equipped with technological functions, e.g. counting pulses, positioning
functions, control of step-action motor power sections.
ET 200S
Manual, 12/2005, A5E00514527-03 Glossary-9