70
EB 8389S EN
Tests
4.4.1
Start triggered by the
set point
The partial stroke test of on/off valves is trig-
gered when the set point w moves in the
range between 25 and 50 % of the travel
and remains there for longer than six sec-
onds. See
u
Section 3.1.
'Step start' must be within the range of the
defined position ± 'Tolerance limit of step
response' for the partial stroke test to start.
The test and its cancelation are described in
u
Section 4.4, while the test assessment is
described in
u
Section 4.4.3.
4.4.2
Start triggered by the
binary input
If the positioner is fitted with the optional bi
-
nary input, the partial stroke test can be
started by the binary input when the condi-
tions to start the partial stroke test are met:
−
A control valve is in the manual mode.
−
An on/off valve is in the manual or auto-
matic mode. In automatic mode, the test
is only started when the 'Fail-safe refer-
ence value' is greater than the 'Limit fail-
safe position' (Code 49 - h2). In manual
mode, the test is only started when 'Tar-
get PST testing mode' = 'PST Man'.
The test and its cancelation are described in
u
Section 4.4, while the test assessment is
described in
u
Section 4.4.3.
It is important to make sure that the diag-
nostic parameter 'Step start' of the partial
stroke test is within the range of the 'Fail-
safe reference value' ± 'Tolerance limit of
step response'.
Settings > Positioner > Options
−
Action at active binary input:
Start partial stroke test (PST)
−
Edge control binary input:
[On: open switch/Off: closed switch], On:
closed switch/Off: open switch
−
Fail-safe reference value: 0.0 to 100.0 %,
[50.0 %]
−
Configuration binary input: [Active], Passive
Note:
Further details on optional binary in-
put
u
Section 6.
4.4.3
Analysis and monitoring
The analysis of the last three partial stroke
tests are saved with a time stamp in the
Analysis of measured data
folder. A graph
of the last partial stroke test is shown in the
Partial stroke test
folder.
Test completed successfully
When a partial stroke test has been complet-
ed successfully, the analyzed parameters are
displayed separately for the increasing and
decreasing characteristics.
Analysis of measured data (step response
test):
−
'Overshoot' (relative to the step height)
[%]
−
'Dead time' [s]
−
'T63' [s]
−
'T89' [s]
Содержание TROVIS SAFE 3731 Series
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