Glossary
35
Stamp
The output byte 0 of a data channel is called the stamp.
Stamp = 0 indicates that the master is ready for data exchange.
If stamp = 0, output byte 2 contains information on the length of
the following user data.
Stamp
≠
0 indicates that user data now follows or that the oper-
ation is completed.
Station address
Address with which the DP master accesses the PROFIBUS
DP slave.
Status byte
→
Mirror
Step 5
Programming language used for user programs for SIMATIC S5
controllers.
Step 7
Programming language used for user programs for SIMATIC S7
controllers.
Step 7 tool
Tool for Step 7 which automates particular programming tasks.
SYNC
Control command that a DP slave receives from the DP master.
It causes the slave to store (freeze) the current states of its out-
puts. When following telegrams are received, it stores the out-
put data, but the states of the outputs remain unchanged. The
outputs are only cyclically updated again after the slave re-
ceives the UNSYNC command.
Telegram
A data flow which is sent or received through the serial interface
(SIO), e.g. when you send a text to a text display or receive a
bar code from a bar code scanner.
Telegram fragment
Part of a send or receive telegram. A telegram must be frag-
mented when it is so large that it cannot be transferred within a
single PLC cycle
Terminating resistor
Used to stop electrical reflections and thus signal distortion at
the end of the bus cable. Terminating resistors are required at
each end of the bus cable.
Tool
Software tool used to specify and change the parameters of a
parameter block.
