Application Data - Honeywell ST 3000 Specification And Model Selection Manual

Application Data*

Liquid Level: Closed Tank
Determine the minimum and
maximum pressure differentials to
be measured (Figure 18).
P Min = (SG p x a) – (SG f x d)
= LRV when HP at bottom
of tank
= –URV when LP at
bottom of tank
P Max = (SG p x b) – (SG f x d)
= URV when HP at bottom
of tank
= –LRV when LP at bottom
of tank
Where:
Minimum level at 4 mA
Maximum level at 20 mA
a = distance between bottom
tap and minimum level
b = distance between bottom
tap and maximum level
d = distance between taps
SG f = Specific Gravity of capillary
fill fluid (see page 11 for
values)
SG p = Specific Gravity of
process fluid
* Contact STC-Phoenix concerning
applications for model STR13D.
Max
Level
b
Min
Level
Transmitter above datum
Max
Level
b
Min
Level
Transmitter at datum
Max
Level
b
Min
Level
Transmitter below datum
Figure 18—Closed tank liquid level measurement distances.
LP
HP
a
LP
HP
a
LP
HP
a
34-ST-03-64
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