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Section 4
Model 753A Gage Pressure Transmitter
Section 4—Calibration and Maintenance
General Field and Periodic Maintenance
Electronic Transmitter
The electronic transmitter circuits are basically maintenance-free and do not
require routine preventative maintenance other than a periodic check of cali
-
bration. See Calibration below for details.
Calibration
Each transmitter is calibrated at the factory prior to shipment. A 9-point cali
-
bration check is recommended upon receipt, and again before the transmitter
is operated for the first time. If "as found" values are not within the specified
range, a full calibration should be performed.
The transmitter should be recalibrated at periodic intervals, determined
primarily by the usage of the transmitter, historical performance, the desired
accuracy of the output signal, or indications that the instrument may be out of
calibration. If a transmitter is installed after an extended period of storage, a
calibration test should be performed before operating the transmitter to ensure
correct performance.
Test Equipment
To perform the calibration procedure for an instrument with 0.5% accuracy,
the test equipment should meet or exceed the requirements listed in
Table 4.1,
page 17
. For calibrating instruments, the pressure source should have at
least 4 times the accuracy of the instrument being tested. In the event equip-
ment is substituted that does not meet these requirements, the accuracy of the
recalibrated transmitter must be derated accordingly.
