72
EB 8389-1S EN
Valve dead band
ST
AR
T-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!
T
he posit
ioner is write-pr
otected when tests ar
e per
for
med ac
cor
ding to a schedule (local oper
at
ion and oper
at
ing softwar
e).
Activate ramp function
â
â
â
100
90
x [%]
t [s]
x [%]
No
Yes
100
90
x [%]
t [s]
â
Ramp time (increasing)
Ramp time (decreasing)
â
Cancelation conditions
Max. test
duration
Max. break-
away time
Perm. time until
step end
x monitoring value
Δp out moni
-
toring value
PST tolerance
band
Status classification (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
â
Test interval
â
â
Test start
â
â
Immediately
Time-con-
trolled*
â
PST 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 defining 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
TES
T/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)