Design And Principle Of Operation - Samson 5757-7 Mounting And Operating Instructions

Design and principle of operation

2 Design and principle of
operation
The Type 5757-7 consists of a digital con-
troller integrated into the housing of an elec-
tric actuator.
The combination is especially designed for
heating applications as well as for fixed set
point control of heating systems in small to
medium-sized buildings. It is particularly
suitable for mounting to SAMSON
Type 3222, Type 3222 N, Type 2488 and
Type 3267 Valves (DN 15 to 25) and to
special versions of Type 3226 and
Type 3260 Valves.
The digital controller is connected to a flow
sensor on the input side, which can be op-
tionally upgraded by a return flow, outdoor
or room sensor.
In addition to the Pt 1000 input, the digital
controller has a potentiometer input (1000
to 1100 Ω or 1000 to 2000 Ω) to measure
the flow temperature. This input influences
the heating characteristic in the case of out-
door temperature compensated control and
the room temperature set point in the case of
fixed set point control with room tempera-
ture influence.
Heating characteristic and set point parame-
ters can be changed over the TROVIS-VIEW
Operator Interface.
The output signal of the integrated digital
controller is applied as a three-point step-
ping signal to the synchronous motor of the
actuator. The signal is transferred over the
connected gear to the actuator stem (3) and
used as the positioning force.
The motor is switched off by torque switches
when an end position is reached or in case
the motor is overloaded. The actuator is
6
EB 5757-7 EN
mounted onto the valve using a coupling nut
(4).
When the actuator stem extends, the valve is
closed, opposing the force of the valve
spring (7). When the actuator stem retracts,
the valve is opened as the plug stem (6) fol-
lows the motion of the return spring.
The valve can be moved to any position by
the handwheel (2) when the power supply
is disconnected. Travel and direction of ac-
tion can be read off the travel indicator (5)
on the side of the actuator housing.
Stem retracts
Stem extends
2
1 Controller with
electric actuator
1.1 Connecting lead
2 Handwheel (only use
when power is dis-
connected)
3 Actuator stem
Fig. 2 · Functional diagram
5
8 1
3 5
4
7
6
4 Coupling nut
5 Travel indicator
6 Plug stem
7 Valve spring
8 Cover, serial
interface connection,
slide switch and LEDs
1.1