Samson 4763 - Electrical Connection

EB 8359-2 EN 5-11
Installation
b) Actuator with “actuator stem
retracts” (FE) fail-safe action
When using an actuator with fail-safe action
"actuator stem retracts", the diaphragm
chamber must be pressurized with a signal
pressure that is high enough to tightly close
the valve against the upstream pressure in
the plant.
Î Operating direction <<: Upper range
value of set point 20mA
Î Operating direction <>: Lower range val-
ue of set point 4mA
The required signal pressure is either indicat-
ed on the positioner label or it can be rough-
ly calculated as described in section5.4.2.
Starting point, e.g. 20mA
1. Set the input signal at the ammeter to
20mA.
Turn the zero adjustment screw (4) until
the plug stem just starts to move out of its
initial position.
2. Increase the input signal and slowly re-
duce it again to 20mA. Check whether
the plug stem starts to move at exactly
20mA.
Correct any deviation at the zero adjust-
ment screw (4). Turning it counterclock-
wise causes the plug stem to move from
its end position earlier; turning it clock-
wise causes it to move from its end posi-
tion later.
Upper range value (span), e.g. 4 mA
3. Once the starting point has been set, in-
crease the input signal to 4mA at the
ammeter.
At exactly 4mA, the plug stem must
stand still, having moved through 100%
travel (watch the travel indicator at the
valve).
4. If the upper range value is incorrect,
move the pin (2) to correct it. Readjust
20mA and turn the zero adjustment
screw (4) until the pressure gauge indi-
cates the required signal pressure.
If no pressure gauge has been installed,
set the starting point to 19.5mA instead.
5.7 Electrical connection
For electrical installation, observe the rele-
vant electrotechnical regulations and the ac-
cident prevention regulations that apply in
the country of use. In Germany, these are
the VDE regulations and the accident pre-
vention regulations of the employers’ liability
insurance.
Incorrect electrical connection will render
the explosion protection unsafe.
Î Adhere to the terminal assignment.
Î Do not undo the enameled screws in or
on the enclosure.
WARNING
!