Assortment / System Description

18
Limitation of sequence with PI control action per controller. Min / max limitation can
be configured. The limitation acts on a single sequence (e.g. heat recovery anti-
icing protection or maximum limitation of air heating coil’s return temperature).
Digital input (heating limit switch of a heating controller) for changeover of control
strategy (room-supply air cascade) is configurable.
This controller controls the mixed air temperature via the air dampers.
Individually adjustable heating and cooling setpoints (or maximum and minimum
setpoints) for Comfort and Economy mode.
Predefined setpoint via the absolute remote setpoint adjuster (active or passive).
Setpoint compensation as a function of some other measuring variable and with
adjustable start and end points.
Preselection with setpoint adjuster, absolute in °C (active and passive), or relative
in K (passive only), or setpoint predefined via the room unit. Room temperature
setpoint with summer and/or winter compensation
The operating mode is predefined via digital input D1 or D2 (e.g. by external time
switch or manual switch). The current operating mode is displayed (Comfort
,
Economy
, Protection ).
2-phase frost protection function (modulating/2-position frost protection) or frost
protection thermostat. Heating sequences at 100% output, fault relay for
deactivating the fans (RLU220 only display).
100 %
0 %
Xp
5 %
Xp/2
2 K
SET-ON
TFrst
3101D13en
On
Off
Heat valve
Heating coil pump
Frost alarm
Frost protection function also remains
active when plant is off
Control of pumps: Permanently on at low outside temperatures, on after load
sequence controller (not RLU220). Periodic activation of pump (pump kick).
Maximum selection is possible in connection with a maximum of 2 RLU-internal
load signals and the external load signal. Example: The external load signal from
an external dehumidification controller (acting on the chilled water cooling coil) is
combined with the RLU-internal temperature controller. The external load signal is
also used as a control signal to control multistage aggregates.
Minimum and maximum limitation of positioning signal and positioning signal
invertible (not possible with RLU202). Minimum limitation at low outside
temperatures. Startup function at low outside temperatures.
Control of mixed air dampers or of the heat recovery system via maximum
economy changeover (not possible with RLU202).
Changeover of control
strategy
Mixed air temperature
controller
Setpoints
Sequence controller
Room temperature
Operating mode
Open loop
control functions
Frost protection
Pump control
External load signal
Positioning signal
(DC 0...10 V)