Emerson Rosemount 1199, Справочное руководство

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4.1.7 Non-zero based lower range value(balanced system with
transmitter below seals)
Figure 4-7: Remote Capillary
L
max
108 in.
SG = 0.75
P
L
min
0 in.
d = 60 in.
H
d = 180 in.
(60 +120)
L
SG = 0.934
F
d
H
= vertical distance from transmitter to high pressure seal
d
L
= vertical distance from transmitter to low pressure seal
L
max
= the maximum level of process above the high pressure seal and typically the 20
mA lower range value
L
min
= the minimum level of process above the high pressure seal and typically the 4 mA
lower range value
SG
F
= specific gravity of fill fluid
SG
P
= specific gravity of process fluid
Tank span = L
max
× SG
= 108 in. × 0.75 = 81 inH
2
O
4 mA = L
min
× SG
P
– (d
L
× SG
F
) +(d
H
× SG
F
)
= (0 in. × 0.75) – (180 in. × 0.934) + (60 in. × 0.934) = –112.08 inH
2
O
20 mA = L
max
× SG
P
– (d
L
× SG
F
) +(d
H
× SG
F
)
= (108 in. × 0.75) – (180 in. × 0.934) + (60 in. × 0.934) = –31.08 inH
2
O
Span = 81 inH
2
O (–112.08 to –31.08 inH
2
O)
Note
Silicone 200 has a specific gravity of 0.934.
Note
The transmitter location in a closed tank does not effect the 4 mA and 20 mA set points as
shown in example A, B, and C.
Reference Manual Configuration
00809-0100-4002 May 2020
Rosemount DP Level 81