7.7
External setting of the air volume
If the function blocks Fb39 and Fb13 are activated, i.e.
variable air volume control
and
ex-
ternal demand for operation
are configured, a potentiometer at input F12 can be used to
trigger an external demand for operation and the air volume can be set. The air volume can
be predetermined between the value
Minimum air volume (MIN AA) and 100 %. The input
F12 is evaluated as follows:
4
Resistance 1000 to 2000
Ω
:
System operation required. Minimum air volume determined by the potentiometer
(potentiometer setting 2000
Ω
equals 100 %).
4
Resistance
∞
(= BE1 open):
System operation according to the times-of-use. Minimum air volume determined by the
controller setting.
Functions
WE
Configuration
External demand of operation with BE1 and
BE4
OFF
Fb13 = ON
Request for externally required signal
OFF
Fb20 = OFF
Variable air volume control over AA
OFF
25 %
0.0
Fb39 = ON
MIN AA (min. air volume) / 0 to 100 %
K
P
(Factor of change)/ 0.0 to 10.0*
* Factor of change for cascade contro only
7.8
External demand for operation
The operation of the ventilation can be controlled with the binary inputs BE1 and BE4.
If the operating mode switch is set to automatic operation (
), the binary inputs BE1 and
BE4 have the following effect:
4
BE1 and BE4 = OFF: Operation of the system corresponding to the times-of-use
4
BE1 = ON, BE4 = OFF: Operation of the system, even outside of the times-of-use
4
BE1 = OFF, BE4 = ON: System out of operation, even within the times-of-use
If the operating mode switch is set to reduced operation (
), only BE1 is relevant for the ex-
ternal demand for operation:
4
BE1 = OFF: System out of operation
4
BE1 = ON: Operation of the system corresponding to the times-of-use
The system starts to run, if necessary, taking into account the system start-up function.
Function
WE
Configuration
External demand for operation with BE1 + BE4 OFF
Fb13 = ON
EB 5477 EN
71
System-wide functions