VEGA VEGAMET 391 With SIL qualification User Manual
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9 Application examples
VEGAMET 391 • With SIL qualification
38704-EN-130228
triggered after the enquiry period. The enquiry period is started as
described above when the relay is switched on.
Switch on reaction of the pump control 2
When the signal conditioning instrument is switched on, the relays are
at first in a switched-off status. Depending on the input signal and the
switched-on period of the individual relays, the following relay switch-
ing conditions can occur after the start procedure:
•
Input signal is higher than the upper switching point -> Relay with
the shortest switch on period is switched on
•
Input signal is between lower and upper switching point -> Relay
remains switched off
•
Input signal is smaller than the lower switching point -> Relay
remains switched off