72 EB 8389-1S EN
Valve dead band
START-UP
Step response settings: Lower range value, Stop, Tolerance limit, Settling time
before starting test, Waiting time after step change, Sampling time, Number of
step responses
* Note! The positioner is write-protected when tests are performed according to a schedule (local operation and operating software).
Activate ramp function
â
â â
100
90
No Yes
100
90
â
Ramp time (increasing)
Ramp time (decreasing)
â
Canc
elation conditions
Max. test
duration
Max. break-
away time
P
erm. time until
step end
x monitoring value
Δp out moni
-
toring value
PST tolerance
band
Status classication (NE 107)
PST/FST
Max. test
duration
exceeded
â
The valve has
not moved
before
reaching the
max.
breakaway
time.
â
The valve has
not reached
the 'Stop'
position
before 'Perm.
time until
step end' has
elapsed.
â
The valve
position has
fallen below
the
monitoring
value.
â
The signal
pressure
change has
exceeded or
fallen below
the
reference
value.
â
The valve
position
deviation
exceeds the
PST tolerance
band.
â
â
Observe start conditions
(see
Table 4
)
â
Test interval
â â
Test start
â â
Immediately
Time-con
-
trolled*
â
PS
T start
â â
Other cancelation causes: solenoid valve trig-
gered/forced venting active; Supply pressure too
low; Too much friction; Step start too large;
Change in set point; Current too low
First PST after dening parameters =
Reference
Other cancelation causes: solenoid valve trig-
gered/forced venting active; Supply pressure too
low; Too much friction; Step start too large;
Change in set point; Current too low
TEST/PROCESS
â
Start further PST
â â â â â â â
Analysis (NE 107)/logged by operating hours counter
PST/FST
â
Reset 'PST parameters'
Partial stroke test (PST)
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