IC 40 · Edition 07.18
48
Function
3 .8 Inputs
3 .8 .1 Digital
In the basic setting, the two digital inputs oper-
ate as universal inputs. If a voltage of 24 V DC or
100 – 230 V AC is applied to the input, this is recog-
nized as “On” signal (positive logic).
Switching logic
The switching logic can be inverted for each individual
digital input. An applied voltage is then recognized as
“Off” signal while no voltage results in an “On” signal
(negative logic). Inversion of the input switching logic
in conjunction with the operating modes provides new
options for defining the behaviour of the actuator.
3 .8 .2 Analogue
The actuator can approach corresponding intermedi-
ate positions via a current signal to the additional input.
This function can be used only if an actuator IC 40 with
4 – 20 mA analogue input is connected (option). The
switch-on and switch-off threshold of the analogue in-
put is defined at approx. 3 mA.
The assignment of current value to position can be free-
ly defined via 5 pairs of values (interpolation points).
Each of the interpolation points at 4, 8, 12, 16 and 20
mA can be assigned a position which the actuator ap-
proaches when the corresponding current signal is
applied. The position is interpolated on the basis of a
linear function in each case between the interpolation
points.
In the case of operating modes 25 and 26, 2 character-
istic curves, each with 5 interpolation points, can be de-
fined. In this case, the digital inputs define which char-
acteristic curve currently applies. This allows the same
current signal to be used to run through two different
capacity ranges, for example for lambda adjustment
or for hot-air compensation, see page 38 (2-point
operation with characteristic curve switchover I) and
page 40 (2-point operation with characteristic curve
switchover II).