VEGA VEGAMET 391 With SIL qualification - Manual (Page 25)

25
7 Setup with the integrated display and adjustment unit
VEGAMET 391 • With SIL qualification
38704-EN-130228
The relay/current outputs are arranged under "Outputs". The relays
3/4 are integrated in the SIL safety concept, hence only limited adjust-
ment options are available compared to relays 1/2.
First of all select the requested mode ("Overfill protection/Dry run
protection").
•
Overfill protection: Relay is switched off when the max. level is
exceeded (safe currentless condition), relay is switched on again
when the level falls below the min. level (switch-on point < switch-
off point)
•
Dry run protection: Relay is switched off when the level falls
below the min. level (safe currentless condition), relay is switched
on again when the max. level is exceeded (switch-on point >
switch-off point)
Due to the SIL rating, the behaviour in case of failure is fix set to "Off".
The following example shows the setting of an overfill protection.
Select the requested mode and save with [OK]. By pushing [->], you
reach the next menu item.
→
Now enter the switching points for switching the relay on and off.
The current output is used to transfer the measured value to a super-
ordinate system, e.g. a PLC, a process control system or a measured
value indication. This is an active output, i.e. the current is provided
actively. The processing must hence have a passive current input. The
current output must always be connected (see chapter "Connection
steps")
The characteristics of the current output is set to 4 … 20 mA and can-
not be changed due to the SIL rating. The behaviour in case of failure
is permanently set to 0 mA.
In the menu item "Display - Indication value", you can set the re-
quested indication value. The following options are available:
•
Percent: adjusted measured value without taking a probably
stored linearization into account
Meas. loop - Outputs
- Relay 3/4
Meas. loop - Outputs
- Current output
Display - Displayed value