Synchronize And Freeze - Danfoss FC 300 Profibus Manual

FC 300 Profibus
How to Control the FC 300

Synchronize and Freeze

The control commands SYNC/UNSYNC and FREEZE/UNFREEZE are broadcast functions.
SYNC/UNSYNC is used to synchronize control commands and/or speed reference to all the connected slaves
(FC 300 Series).
FREEZE/UNFREEZE is used to freeze the status feedback in the slaves to get synchronized feedback from all
connected slaves.
The synchronize and freeze commands affect only process data (the PCD part of the PPO).
SYNC/UNSYNC
SYNC/UNSYNC can be used to obtain simultaneous reactions in several slaves, for example synchronized
start, stop or speed change. A SYNC command will freeze the relevant control word and speed reference.
Incoming process data will be stored but not used until a new SYNC command or a UNSYNC command
is received.
An UNSYNC command stops the synchronisation mechanism and enables normal DP data exchange.
FREEZE/UNFREEZE
FREEZE/UNFREEZE can be used for simultaneous reading of process data, for example output current,
from several slaves.
A FREEZE command will freeze the actual values and upon request the slave will send back the value that
was present when the FREEZE command was received.
Upon receipt of an UNFREEZE command the values will once again be continuously updated and the slave will
return a present value, i.e. a value generated by conditions at present time.
The values will be updated when a new FREEZE or UNFREEZE command is received.
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MG.33.C2.02 - VLT is a registered Danfoss trademark