Siemens ET 200pro Operating Instructions Manual page 536

Glossary
SYNC
Control command that the DP master sends to a group of DP slaves.
The DP master outputs a SYNC control command to the DP slave in order to freeze the
slave's outputs at the current value. The DP slave stores the output data contained in the
next frames, but does not change the state of its outputs.
After each new SYNC control command, the DP slave sets the outputs it saved as output
data. The outputs are not updated cyclically again until the DP master has sent a UNSYNC
control command.
Terminating module
The ET 200pro distributed I/O system is terminated with a terminating module. An ET 200pro
is not ready for operation without an inserted terminating module.
WAN
Wide Area Network; extends beyond LAN limits and allows worldwide communication. Legal
rights do not belong to the user, but to the provider of the WAN networks.
536
ET 200pro distributed I/O system
Operating Instructions, 03/2013, A5E00335544-08