Festo HGPPI Series, Instructions Manual

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4. Commissioning
4−31
Festo P.BE−HGPPI−PB−E N en 0605NH
4.5.6 FREEZE and SYNC
The HGPPI−... supports the PROFIBUS control commands
SYNC and FREEZE. If a PROFIBUS master sends these control
commands, the internal I/Os, which are used for communica
tion, are handled as follows:
C au tion
In the following cases, the FREEZE or SYNC mode will auto
matically be reset:
Switching the HGPPI−... on/off
Stopping the fieldbus master
The FREEZE mode will also be reset automatically in the
following case:
When the bus connection to the HGPPI−... is interrupted
(watchdog monitoring active).
FREEZE All inputs of the HGPPI−... are frozen.
The HGPPI−... now sends a constant image of all the inputs
to the master. With each further FREEZE command, the input
image is updated and is constantly resent to the master.
Return to normal operation: UNFREEZE command
SYNC The outputs of the master are mapped on internal inputs of
the fieldbus module (= setpoint values). With this control
command the internal inputs can be frozen." The HGPPI−...
then no longer reacts to modifications to the output image
in the master. The following SYNC command causes the out
put image of the master to be updated.
Return to normal operation: UNSYNC command