Festo FB16, Electronic Manual, Page: 120 / 190

Shutdown behaviour of outputs
(HOLD/STOP)
In normal operation the valve terminal outputs
behave in accordance with the commands from
the PLC program. At the end of each operating
cycle they will be set/reset in accordance with
the values sent by the application program.
However, a number of events can occur during
operation which require to be differentiated:
•
STOP - the outputs of the valve terminal are
switched off on every event (error).
•
HOLD - in certain cases the outputs retain
their current status.
The following table shows the events on which a
HOLD operation is possible:
Event Shutdown behaviour
FIPIO bus interruption optional shutdown of output (STOP)
or
maintenance of the last value received
(HOLD)
Internal fault in the valve terminal
•
Module fault
•
Output short circuit/overload
Device to STOP
Fig. 4/16: Output shutdown behaviour
VIFB16 - 03/05 4. Commissioning
4-38
0506b