Functions such as return air temperature limit, summer compensation, manual set point cor-
rection or condensation detection can shift the set point.
Functions
WE
Configuration
Control method
Exhaust air control (–> page 17)
Sensor F2, exhaust air temperature
or
assignment of inputs AE1 to AE4
OFF
Fb2 = ON or
Fb18 = ON,
option:
AE3F2
Parameters
WE
Range of values
Exhaust air temperature set point
22 °C
0 to 40 °C
K
P
0.5
0.1 to 99.9
T
N
60 sec 1 to 999 sec
T
V
– – –
– – – to 999 sec
5.1.3 Exhaust air temperature cascade control
The sensor input F2 is the control variable input for the exhaust air temperature and the sen-
sor input F1 is the control variable input for the supply air temperature by default. Alterna-
tively, the exhaust air temperature can also be guided over the analog input AE3 and the
supply air temperature over the analog input AE1 to the controller.
The exhaust air temperature control loop is implemented as a P control loop with adjustable
Exhaust air temperature set point and K
P
Temperature of the master loop. The supply air tem-
perature is controlled by a PID control algorithm with adjustable
Temperature set point of
slave loop. Depending on the system code number, the supply air temperature control loop
has between 1 and 3 sequence outputs that are adapted to the dynamics of the correspond-
ing system components by means of the
K
P
, T
N
and
T
V
control parameters. The parameters -
Supply air temperature minimum limit and Supply air temperature maximum limit - restrict
the set point shift which arises when the exhaust air temperature control loop takes influence
on the supply air temperature control loop:
Each deviation in exhaust air temperature by the amount x causes a shift of the supply air
temperature set point by the amount x multiplied by the parameter
K
P
Temperature of the
master loop.
4
x = Exhaust air temperature set point – Exhaust air temperature actual value
4
Temperature set point of slave loop
calculated
=
Temperature set point of slave loop + x · K
P
Temperature master loop
Note!
If the calculated set point is not within the limit, the minimum or maximum limit applies as
the new set point.
38
EB 5477 EN
Control methods and system components