The system runs at an air volume of 75 % to reduce the excess temperature more quickly.
The air quality control is implemented by a PI control algorithm with the parameters
K
P
Air
quality control and T
N
Air quality control.
The operating action of the air quality input can be reversed. The default setting is an air
quality of 0 to 100 % which corresponds to an input signal of 0 to 10 V. L 0 means an insuf-
ficient air quality.
By activating the function block Fb24, the operating action is reversed: air quality 0 to
100 % then corresponds to 10 to 0 V. As a result, L 0 means a very good air quality.
Functions
WE
Configuration
Assignment of inputs AE1 to AE4
OFF
Fb18 = ON,
option:
AE4L
Request for externally required signal
OFF
Fb20 = OFF
Variable air volume control over AA
OFF
25 %
0.0
Fb39 = ON
MIN AA (minimum air volume) / 0 to 100 %
K
P
(Factor of change) / 0.0 to 10.0*
Operating action L
OFF
Fb24
* Factor of change with cascade control only
Parameters
WE
Range of values
Air quality set point
50
0 to 100
K
P
Air quality control
0.5
0.1 to 99.9
T
N
Air quality control
60 sec 1 to 999 sec
52
EB 5477 EN
Control methods and system components