VEGA VEGAMET 391 4 … 20 mA_HART User Manual
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8 Application examples
VEGAMET 391 • 4 … 20 mA/HART
36032-EN-130701
•
Pump control 1: The upper switching point determines the switch-
off point for the relay, whereas the lower switching point deter-
mines the switch-on point
•
Pump control 2: The upper switching point determines the switch-
on point for the relay, whereas the lower switching point deter-
mines the switch-off point
Two pumps should empty the vessel when a certain level is reached.
At 80 % filling, the pump with the shortest running time should switch
on. If the level nevertheless increases, a second pump should switch
on at 90 %. Both pumps should switch off again at 10 % filling.
Select in the DTM navigation section the menu items "Meas. loop -
Outputs - Relay".
•
Set mode "Pump control 2" for relay 1 and 2.
•
Enter the switching points for the affected relays as follows:
– Relay 1 upper switching point = 80.0 %
– Relay 1 lower switching point = 10.0 %
– Relay 2 upper switching point = 90.0 %
– Relay 2 lower switching point = 10.0 %
The function of pump control 2 is shown in detail in the following dia-
gram. The previously described example is used as a basis.
Rel. 1: 80% On
On
Off
Off
On
Rel. 2: 90% On
Rel. 1, 2: 10% Off
10
30
20
20
15
t [h]
5
Rel. 1
Rel. 2
Fig. 14: Example of pump control 2
When pump control is activated, the assigned relays and possible
pump malfunctions are also displayed in the measured value indica-
tion.
Example
Setup
Display indication