3.6 Characteristics
Actual value signal
Fig. 11: Characteristic of the actual value signal 0–10 V
The actual value volume flow rate can be tapped as a
voltage signal at the terminal (U). The measuring range
is factory-adjusted to the size of the VAV terminal unit,
so that the respectively rated nominal volume flow rate
(V
Nom
) always corresponds to an actual value signal of
10 V DC. The current actual value volume flow rate can
be calculated from the measured voltage at the output
(U) using the formula below.
Setpoint value signal
Fig. 12: Characteristic of the reference signal 0–10 V
In order to specify a volume flow rate setpoint value to
the Easy controller, a DC voltage signal in the range of
0–10 V DC must be applied to terminal (w).
The relationship between the nominal volume flow rate
and the associated voltage signal can be calculated
from the formula below. The setting of the potentiome-
ters V
min
and V
max
must be taken into account.
The default settings of the working range V
min
= 40 %
and V
max
= 80 % can be easily changed by the cus-
tomer.
Calculation example:
V
nom
of the VAV terminal
unit:
- 800 m³/h
V
min
- should be 200 m³/h
V
max
- should be 600 m³/h
At a setting of V
min
= 0 % and V
max
= 100 %, the control-
ling unit can specify the entire nominal volume flow rate
range of the VAV terminal unit as a setpoint value.
If V
min
and V
max
are set to only a partial range of the
nominal volume flow rate range; a higher resolution for
the control input signal is available for this work area. In
the first case, the limitation of the setpoint signal to the
work area must be taken into account by the superordi-
nate rule instance,
Chapter 6.1.1 ‘Control ranges of
VAV terminal units’ on page 22
Structure and functional description
Characteristics
Control component Easy for VAV terminal units
16
