Emerson Model 1700 Manuel D’Utilisation
Effect of Flow Direction on the mA output: Lower Range Value < 0
Figure 4-2:
Flow Direction = Forward
mA output
-x
0
x
Reverse flow
Forward flow
20
12
4
Flow Direction = Reverse, Negate Forward
mA output
-x
0
x
Reverse flow
Forward flow
20
12
4
Flow Direction = Absolute Value, Bidirectional,
Negate Bidirectional
Negate Bidirectional
mA output
-x
0
x
Reverse flow
Forward flow
20
12
4
•
Lower Range Value
=
−x
•
Upper Range Value
= x
Example: Flow Direction = Forward and Lower Range Value = 0
Configuration:
•
Flow Direction
= Forward
•
Lower Range Value
= 0 g/sec
•
Upper Range Value
= 100 g/sec
Result:
•
Under conditions of reverse flow or zero flow, the mA output is 4 mA.
•
Under conditions of forward flow, up to a flow rate of 100 g/sec, the mA output
varies between 4 mA and 20 mA in proportion to the flow rate.
varies between 4 mA and 20 mA in proportion to the flow rate.
•
Under conditions of forward flow, if the flow rate equals or exceeds 100 g/sec, the
mA output will be proportional to the flow rate up to 20.5 mA, and will be level at
20.5 mA at higher flow rates.
mA output will be proportional to the flow rate up to 20.5 mA, and will be level at
20.5 mA at higher flow rates.
Example: Flow Direction = Forward and Lower Range Value < 0
Configuration:
•
Flow Direction
= Forward
•
Lower Range Value
=
−100 g/sec
•
Upper Range Value
= +100 g/sec
Result:
•
Under conditions of zero flow, the mA output is 12 mA.
•
Under conditions of forward flow, for flow rates between 0 and +100 g/sec, the mA
output varies between 12 mA and 20 mA in proportion to (the absolute value of) the
flow rate.
output varies between 12 mA and 20 mA in proportion to (the absolute value of) the
flow rate.
Configure process measurement
Configuration and Use Manual
41