Rosemount 1151GP - Page 59

Reference Manual
00809-0100-4360, Rev BA
August 2008
4-9
Rosemount 1151
Low Trim (LT) = LRV + S (LRV) P
WhereLT = Corrected Low Trim Value at Atmosphere
LRV = Lower Range Value at Pressure P
S = Span Shift from Table 4-2
P = Static Line Pressure
High Trim (HT) = URV + S (URV) P
WhereHT = Corrected High Trim Value at Atmosphere
URV = Upper Range Value at Pressure P
S = Span shift from Table 4-2
P = Static Line Pressure
Example 1
A Rosemount 1151DP Range 4 transmitter is to be calibrated 0–90 inH
2
O and
used in an application where static line pressure is 1,200 psi.
Looking at Table 4-2 you see the Range 4 span is reduced by 0.90% per
1,000 psig. At 1,200 psi the span would be reduced by 1.08 percent.
0.009 X 1.2 = 1.08%
Analog Electronics
There are two ways to calibrate an analog transmitter for this application.
One method is to increase the pressure when adjusting the span. Another
method is to apply the span pressure and increase the mA output.
1. Apply 0 inH
2
O pressure and adjust the output to 4mA. then apply 90.97
inH
2
O pressure and adjust the output to 20 mA.
90 inH
2
O  1.08% =0.97 inH
2
O
90 inH
2
O ±0.97 inH
2
O = 89.03 inH
2
O
2. Apply 0 inH
2
O pressure and adjust the output to 4mA. then apply 90
inH
2
O pressure and adjust the output to 20.173 mA.
16 mA  1.08% =0.173 mA
Smart Electronics
There are also two ways to calibrate a smart transmitter for the above
mentioned application. One way is to rerange the transmitter; the other way is
to perform a sensor trim.
1. Using a Field Communicator, configure the range points to 0–89.03
inH
2
O.
2. Using a Field Communicator, perform a sensor trim. Select Hi Val and
apply 90 inH
2
O pressure. When the communicator asks what pressure
you applied enter 89.03 inH
2
O. Set the range points to 0–90 inH
2
O.
Example 2
A Rosemount 1151HP Range 5 transmitter with Alloy C-276 diaphragms is to
be calibrated at 0–220 inH
2
O and used in an application where the static line
pressure is 2,300 psi.
Looking at Table 4-2 we see the Range 5 with Alloy C-276 diaphragms span
is reduced by 0.70 percent per 1,000 psig. At 2,300 psi the span would be
reduced by 1.61 percent.
0.007  2.3 - 1.61%