Samson foundation 3787, Mounting And Operating Instructions, Page: 31 / 96

4.4.2 Initialization
After connecting the supply air and electri-
cal connections to the bus cable, initializa-
tion must be started. During initialization,
the positioner adapts itself optimally to the
friction conditions and signal pressure re-
quirements of the control valve.
Caution!
Initialization takes several minutes to
complete. During this time, the con-
trol valve moves. Therefore, never in-
itialize while a process is running,
but only during the start-up phase
when the shut-off valves in the plant
section are closed. Alternatively,
remove the control valve with posi-
tioner from the plant and initialize
on a test bench.
Enter data on valve and actuator under
"Start-up" in the operating software.
Set "Type of initialization" to "Rated
range", select "Maximum range" only
for three-way valves.
Start initialization.
A successful initialization is indicated in the
operating software and over the LEDs (see
chapter 4.1).
Carry out the configuration suitable for
the valve type.
The following setting is recommended:
Fail-safe position "Actuator stem ex-
tends":
Direction of action: increasing/increas-
ing (>>), the globe valve opens with in-
creasing reference variable
Final position at a reference variable
less than 1% (tight closing),
Dimensions
Fig. 11
⋅
View of the positioner cover open
GW1
GW2
3785
LED 1 LED 2
0
PE
IEC 1158-2
S
NC
-5
2
+5
1
-42
+4
1
-86
+85
-82
+81
0N
0FF 0FF
Caution! V
alve actuates
Init/Zero
SERIAL INTERF
ACE
FOUNDA
TION
Fieldbus
Simulation enable Write protection
GW2
GW1
Arrow for mounting
position
Manual operation
Zero switch
Pointer
Adjustment screws for
limit switches
Key for initialization
and zero calibration
Metal tags
LED
Serial interface Simulation switch
Write protection
switch
EB 8383-1 EN
31