Application Note

Automated field calibration for
the oil and gas industry
How to save time and money and reduce risk:
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Technicians that maintain and
troubleshoot process automa-
tion systems used in refineries,
pipeline custody transfer appli-
cations, or pumping operations
know that there are thou-
sands of sophisticated devices
required to perform countless
critical operations ceaselessly,
accurately, and reliably. Those
devices require regular inspec-
tion, testing, calibration, and
repair to protect the health and
safety of the public. Businesses
and governments require highly
specific documentation of those
maintenance and calibration
tasks performed on these critical
assets.
Traditional calibration and
documentation practices are
labor-intensive and in today’s
downsized environment there
simply aren’t the resources to
keep up. However, automated
calibration practices are prov-
ing a practical alternative
because they require smaller
teams, increase productivity and
operational reliability at a lower
overall cost.
Increased safety and
productivity. Reduced costs
Whether you’re installing a
new device, changing the set-
tings of an existing device, or
reinstalling a repaired device,
calibration is the only way to
ensure that the device meets
performance requirements. This
is important for:
• Safety. When valves and
gauges are not regularly cali-
brated, they can fail, cause
an unsafe condition possibly
leading to an explosion, loss of
life and cause great damage to
infrastructure.
• Quality. To perform at the
highest efficiency and quality,
equipment must be well main-
tained and adjusted.
• Revenue. Calibration of the
devices that make custody
transfer measurements, are nec-
essary to insure that purchased
products, such as gasoline or
natural gas, are measured and
taxed correctly.
• Compliance. Government
regulation and enforcement
agencies often require cali-
bration and documentation to
verify that devices conform
to rules and standards. Poor
calibration documentation can
put the manufacturer at risk of
government fines and loss of
production.
• Cost savings. With automated
calibration and documenta-
tion a lean team can complete
twice as many calibrations in
the same amount of time, which
lowers the cost per calibration
significantly. Regular calibra-
tion can also reduce the risk
of lost revenue from accidents;
if a disaster strikes, good cali-
bration records can support a
strong defense against legal
action.
Dispelling myths
In the oil and gas industry there
is a widespread belief that field-
bus (digital) field devices do not
require calibration. This is not
true. A fieldbus signal provides
diagnostic information; it does
not provide information about
the accuracy of the device, nor
does it verify that the device is
reporting the process accurately
and precisely.
For example, a Foundation
fieldbus differential pressure
transmitter can report diagnostic
information about the transmit-
ter, but it cannot report on the
physical condition of the orifice
plate across which it is mea-
suring pressure. Consequently,
even if the electronics are oper-
ating perfectly, the flow reading
transmitted may be inaccurate.
Calibration is required to ensure
the flow reading is accurate.
Addressing documentation
challenges
Traditionally, documenting a
calibration has meant hand
writing the results on a clip-
board or in a log book. Pencil-
and-paper documentation both
produces and perpetuates
errors. The data in handwrit-
ten records is often illegible
or insufficient. And, facilities
that use a computerized main-
tenance management system
(CMMS), must allot additional
time to manually enter the