76
EB 8389-1S EN
Partial stroke test (PST)
−
Cancel internal solenoid valve/forced
venting: The test was canceled by the ac-
tivation of the solenoid valve/forced
venting function.
−
Canceled by control loop error: A control
loop error has occurred.
−
Set point start difference too high: During
the step change, 'Lower range value' is
outside the range (operating point ± 'Tol
-
erance limit').
−
Set point change: Time-controlled start of
the test. Due to a set point change before
the step change, 'Lower range value' is
outside the range (operating point + 'Tol
-
erance limit').
−
Current too low
−
Supply pressure too low
−
Electric current change: The partial stroke
test of a control valve is canceled when
the change in electric current ≥ 'Tolerance
band' (Code 19) arises.
The partial stroke test of an on/off valve
is canceled when the valve moves from
the operating position to the fail-safe po-
sition or from the fail-safe position to the
operating position due to a change in
electric current.
Note:
The 'Measured data storage out of
memory' reading (Failure) is generat-
ed when the 'Sampling time' is too
low. After recording 100 measured
values per variable, logging is
stopped, but the test continues until it
is completed.
After the partial stroke test is canceled, the
'PST status' reading indicates 'Not success
-
ful'. The reason for cancelation is marked by
the 'Failure' message in the
Measured data
assessment
folder (> Current test).
Defining parameters
1.
Define parameters for the partial stroke
test. See also
. (The de-
fault settings partly depend on the clos-
ing position ATO/ATC.)
2.
Define parameters for cancelation condi
-
tions.
3.
Select classification for status messages.
4. Start the partial stroke test.
The 'Test information' status indicates
'Test active'. 'D4' and 'TEST' are indicat
-
ed in alternating sequence on the posi-
tioner display. 'Function check'
is ac-
tivated as the condensed state.
1.
Diagnostics > Monitoring/tests > Dynamic
tests > Partial stroke test (PST)
−
Lower range value (Code 49 - d2): 0.0 to
100.0 %, [ATO: 100.0 %; ATC: 0.0 %]
−
Stop (Code 49 - d3): 0.0 to 100.0 %
[ATO: 90.0 %; ATC: 10 %]
−
Tolerance limit: 0.1 to 10.0 %, [2.0 %]
−
Activate ramp function (Code 49 - d4):
[Yes], No
−
Settling time before starting test
(Code 49 - d7): 1 to 240 s, [2 s]
−
Waiting time after step change
(Code 49 - d8):
1.0 to 240.0 s, [2.0 s]
−
Sampling time (Code 49 - d9):
0.2 to 250.0 s, [0.8 s}
