Siemens SIMATIC ET 200M Manual page 227

Glossary
STEP 7
Programming language for developing user programs for SIMATIC S7 PLCs.
Substitute value
Substitute values are values that are issued to the process in the event of failed
signal output modules or that are used in the event of failed signal input modules
in the user program instead of a process value. The substitute values must be
specified by the user (e. g. retain the old value).
SYNC
This is a control command of the DP master to a group of DP slaves.
By means of the SYNC control command the DP master causes the DP slave to
freeze the current statuses of the outputs. In 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.
Terminating resistor
This is a resistor required for the purpose of adaptation on the interconnecting
cable; terminating resistors are always required at the end of cables and
segments.
In the case of the ET 200, the terminating resistors are switched on and off in the
³ bus connector.
Time stamp
This is the date and time specified for a message.
Glossary-10
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Distributed I/O Device ET 200M
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