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Establish optimum loop performance
To ensure any control loop is able to con-
sistently perform within required param-
eters it is necessary to establish the per-
formance requirements of the control
valve. The EnTech control valve dynamic
specification, version 3, and the ISA stan-
dard SP75.25 both detail dynamic per-
formance criteria that must be complied
with if the valve is to have a minimal
impact on process loop variability.
Criteria include non linearities, step
response and valve sizing.
Emerson has been performing dynamic
performance tests on control valves
since the early 1990s. Five PlantWeb
®
dynamic performance loops in Europe,
USA and Asia have been used to build
up an extensive knowledge base con-
cerning control valves that are most
effective in enabling process loops to
control variability. The knowledge
gained, coupled with many years of
field experience has been verified by
subjecting the valves in question to
closed loop dynamic testing to simulate
the plant environment.
All tests performed within Emerson’s
laboratories are conducted in accor-
dance with independent test specifica-
tions
1
, to ensure they are unbiased.
Control valve performance tests clearly
prove that valve type, valve design and
valve manufacturer can have a signifi-
cant impact on process performance.
Following the selection of the correct
valve design and size to match process
needs, Emerson will tune the valve
assembly to ensure optimal installed
performance. Diagnostic tests are per-
formed in manufacturing that will estab-
lish a performance benchmark.
To ensure a control loop
is able to consistently
perform within the
required parameters it is
necessary to establish
the performance require-
ments of the control
valve.
1
Flow Capacity tests performed in accordance with
IEC 60534-2-3, Noise tests in accordance with IEC
60534-8-2, Fugitive Emissions to ISO 15848-1 and
Valve Performance in accordance with control valve
dynamic specification, version 3’, from EnTech and
ISA standard SP75.25.