Siemens SIMATIC S7-300 Hardware And Installation Manual page 233

Segment
--> Bus Segment
SFB
--> System function block
SFC
--> System function
Shared data
Shared data can be addressed from any --> code block (FC, FB, OB). In detail, this
refers to memories M, inputs I, outputs Q, timers, counters and data blocks DB.
Absolute or symbolic access can be made to shared data.
Signal module
Signal modules (SM) form the interface between the process and the PLC. There
are digital and analog I/O modules (input/output module, digital or analog).
Slave
A slave can only exchange data on --> Master request.
Startup
RESTART mode is activated on a transition from STOP mode to RUN mode. Can
be triggered by the --> mode selector switch or after power on, or by an operator
action on the programming device. An S7–300 performs --> a restart.
STEP 7
Programming language for developing user programs for SIMATIC S7 PLCs.
S7-300 Programmable Controller Hardware and Installation
A5E00105492-01
Glossary
12-13