Basic Documentation

8.7 3-position output (3-POINT)
8.7.1 Purpose and activation
The 3-POINT (3-position output) function block controls a modulating controlling
element (valve) with a 3-position actuator (open / standstill / close). This requires 2
switching outputs (open / close).
Purpose of 3-POINT
You can only activate the 3-position output in the RLU202 and RLU222 universal
controllers. To do so, make setting "3P" on the configuration menu.
Activation
Relays Q1 and Q2 must not be occupied by other functions.
L
G
G
G0
G0
N
3101A14
AC 230 V AC 24 V
Q24
Q23
Q12 Q14
Q11
N1
N2
N1
Y1 Y2
N
Y
Connection diagram
For 3-position control of a controlling element operating on AC 230 V, you must
activate the interference suppression element in the controller. To do so, connect
terminal N1 to the neutral conductor, and install a wire link between N1 and N2.
Note
8.7.2 Operating principle
The controller uses the duration of the open and close commands and the entered
actuator running time (ACTTIME) to calculate the actuator's present position
(stroke model). This is compared with the present positioning setpoint. If the result
is a deviation, the controller issues an open or close command.
Calculation of
positioning signal
When the actuator reaches the end positions (fully closed or fully open), the
controller synchronizes the actuator with the stroke model (end position
synchronization). To do so, the controller issues the appropriate positioning
command for a period 1.5 times the entered actuator running time (ACTTIME).
Synchronization
If the actuator shall maintain the end position, end position synchronization (see
above) is repeased at 10-minute intervals.
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Siemens Universal Controllers RLU2… CE1P3101en
Building Technologies Aggregates 29.08.2008