Rosemount 1199 - Calibrating a One-Seal System With Suppressed Zero

3-3
Calibration
FIGURE 3-1. Transmitter Mounted Below the High Side Tap.
1. Calculate the amount of zero suppression by multiplying the
distance between the process connection and the transmitter (h) by
the fill fluid specific gravity (s
f
).
American Units Zero Suppression= (h)(s
f
)
= (40 inches) (0.93 inH
2
O/inch) = 37.2 inH
2
O
2. Calculate the span by multiplying the maximum process fluid
height (H) by the specific gravity of the process liquid (s
p
).
Step 2 Span = (H)(s
p
)
= (120 inches) (1.2 inH
2
O/inch) = 144 inH
2
O
3. Calibrate the transmitter using the following equation:
Step 3 Calibration = Zero Suppression to (Zero Suppression + Span)
= 37.2 to (37.2 + 144 inH
2
O)
Step 4 = 37.2 to 181.2 inH
2
O
SI Units
Calibration
Summary Therefore, in this example, a Model 3051C Range 2, URL = 250 inH
2
O
(620 mbar), Model 1151Range 5, URL = 750 inH
2
O (1,9 mbar), or Model
2088 Range 0, URL = 220 inH
2
O (550 mbar) transmitter is required.
NOTE
Calibrating a One Seal System With Suppressed Zero
(Transmitter Mounted Below the High Side Tap)
H
h
Given:
DC 200 fill fluid
(s
f
) = 0.93 in H
2
O/inch
(h) = 40 inches
(s
p
) = 1.2 in H
2
O/inch
(H) = 120 inches
Given:
Fill fluid
(r
f
) = 930 kg/m
3
(h) = 1 meter
(r
p
) = 1 200 kg/m
3
(H) = 3 meters
(g) = 9,81 m/s
2
4mA
20mA
Zero Suppression ρ
f
gh⋅⋅ 930 9 81,
1
100
---------
mbar⋅⋅ 91 2, mbar== =
Span H ρ
p
g⋅⋅
3
100
---------
1200 9 81 mbar,⋅⋅ 353 mbar== =
4mA Zero Suppression
91 2 mbar,
==
20m
A
Zero Suppression= Span+
91 2 mbar, 353 mbar+=
444 2 mbar,
=
1mbar
100
-----------------------
1kg m
3
⁄()1m s
2
⁄()1m()⋅⋅1N m
2
⁄==
1199-0160J
Step 1
Step 2
Step 3
Step 1