Samson 3730-3 Operating Instructions Manual page 54

Statistical information
− Required transit time OPEN (Code 21):
Variable
− Required transit time CLOSED (Code 22):
Variable
Based on the operating point, the test is per-
formed with a change in travel of less than
1 % to find the change in drive signal (∆y).
The changes in drive signal ∆y are classified
according to the valve position x in the valve
position classes. The average value ∆y per
valve position class is calculated from all the
values and plotted in a graph (Measure-
ment).
Note
− If the test is started in manual mode using
the setting 'Enable time distance' = 'User
defined' and another test is active at the
time selected, the hysteresis test starts 30
seconds after the active test ends.
− A straight line from the average reference
data is shown in cases where no data
could be compiled for valve working rang-
es which were not covered by the long-
term monitoring.
− If the hysteresis test could not be completed
because the valve position is at the top or
bottom limit of the working range, the po-
sitioner generates the message (Test infor-
mation) 'Test at operating point not possi-
ble'.
Short-term monitoring
To provide a short-term trend, the last ten
valve positions x and the associated changes
in drive signal (∆y) values are saved in the
'Short-term' folder.
54
Requirements
1. A single-acting actuator is mounted on
the valve.
2. No booster is mounted on the control
valve.
3. The valve operates as a control valve.
4. A reference test has been performed (see
section 2.4.1).
Settings > Identification > Positioner > Actu-
ator
1. − Model: Single acting, [-/-]
2. − Booster: Not present, [-/-]
Start-up
3. − Application type
valve]
Setting cannot be made in Type 3730-4. In
1)
this case, the application type = Control valve
Defining parameters
1. Select classification for status messages.
2. Set cancellation condition (see sec-
tion 4.7.1).
3. Define start conditions.
4. Start hysteresis test.
The 'Test information' status indicates
'Running test'. 'd5' and 'tESt' are indicat-
ed in alternating sequence on the posi-
tioner display. 'Function check'
vated as the condensed state.
Types 3730-2/-3/-4/-5 (1.5x) and Type 3731-3:
(Code 49 - h0): [Control
1)
is acti-
EB 8389 EN