Siemens LMS14 User Manual

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Building Technologies Division User Manual LMS14... CC1U7471en
6 The settings in detail 07.05.2014
6.10.2 Mixing valve control
Line no. Operating line
2130 Mixing valve boost
To ensure accurate control, the flow temperature delivered by the boiler must be higher
than the flow temperature setpoint demanded downstream from the mixing valve. For
this reason, the controller generates the boiler temperature setpoint based on the
mixing valve boost set here and the current flow temperature setpoint.
Line no. Operating line
2132 Actuator type
2-position
3-position
The selected type of actuator determines the control action of the mixing valve actuator
used.
2-position
The controller drives the actuator via one relay output. When a control signal is
delivered, the valve opens. When there is no control signal, the valve closes
automatically (thermal or mechanical action).
Note!
The control employs a 2-position controller with an adjustable switching differential. If
the flow temperature lies more than half the switching differential below the setpoint,
relay Mixing valve Open is energized to remain energized until the flow temperature
reaches a level half the switching differential above the setpoint.
3-position
The controller drives the actuator via 2 relay outputs. One of the outputs is used for
opening the valve, the other for closing it. If none of the relays is energized, the
actuator maintains its present position.
Note!
The control employs a PID controller whose proportional band (Xp) and integral
action time (Tn) can be parameterized. The actuator’s running time can also be
adjusted. The controller’s neutral zone is ±1 K. The control parameters can be
matched to the requirements of difficult controlled systems.
Line no. Operating line
2133 Switching differential 2-pos
With 2-position actuators, the 2-position switching differential must be adapted also.
This is not required with 3-position actuators.
Line no. Operating line
2134 Actuator running time
Setting the running time of the actuator used with the mixing valve.
Line no. Operating line
2135 Mixing valve Xp
By setting the right proportional band Xp, the control action of the mixing valve’s
actuator is matched to the behavior of the plant (controlled system).
The proportional band influences the controller’s P-control action.
Mixing valve boost
A
ctuator type
Switching differential
2-pos
A
ctuator running time
Mixing valve Xp

Siemens LMS14 Specifications

General

Brand	Siemens
Model	LMS14
Category	Control Unit
Language	English