Endress+Hauser RMA 422, Operating Instructions Manual

Page: 65 / 150

The following instrumentation is suitable to solve this
application:
•
2 pressure sensors, in order to measure the head
and bottom pressure.
•
Process transmitter for the power supply of both
pressure sensors, calculation of the volume using
the pressure difference as well as the output and
monitoring the head pressure and volume.
•
2 field displays front-end indication.
Calculation of the tank volume is done in three stages:
1. Transmission of the head and base pressure to the input of
the process transmitter in pressure units. Here the scaling of
the pressure sensors is done:
2. Calculation of the differential pressure in pressure units by
the mathematics channel:
Menu group Parameter Set-up
Analogue input 1
IN1
(base pressure [bar])
Input range
RANG1
Curve
CURV1
Measured value decimal point
DIDP1
Meas. value scale 0%
DILO1
Meas. value scale 100%
DIHI1
4-20
LINAR
999,99
000,00
003,50
Analogue input 2
I
N2
(head pressure [bar])
Input range
RANG2
Curve
CURV2
Measured value decimal point
DIDP2
Meas. value scale 0%
DILO2
Meas. value scale 100%
DIHI2
4-20
LINAR
999,99
000,00
001,00
Menu group Parameter Set-up
Mathematics channel
MATH
(differential pressure [bar])
Operator
MAOP
Factor 1 decimal point
FADP1
Factor 1
FA1
Factor 2 decimal point
FADP2
Factor 2
FA2
Result decimal point
MADP
SUB
99999
00001
99999
00001
999,99
Process transmitter
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