IC 40 · Edition 07.18
9
Application
1 .1 .5 Continuous control with defined ignition position
The central control system starts the pre-purge. Input
DI 2 is activated via the air valve output of the BCU and
the butterfly valve BVA is set to the pre-purge position.
In the event of a temperature demand, the burner con-
trol unit BCU activates input DI 1 via the valve output
V1 and moves the butterfly valve to the ignition position
(precondition: the IC 40 must have reached the ignition
position on the instant of ignition). The burner starts.
The BCU activates DI 2 via the air valve output. This
enables the analogue input IN on the actuator IC 40.
Depending on the capacity demand of the temperature
controller, the butterfly valve BVA moves steplessly to
the position between the low-fire rate and the high-fire
rate as specified by the analogue input IN (see Operat-
ing mode 27, 2-stage operation with two digital inputs
and variable adjustment angle for the open position).
DI 1/V1 DI 2/air valve IC 40 position
Valve position
Off
Off
closed
Closed
On
Off
low
Ignition position/low-fire rate
On
On
analogue chart 1
In acc. with chart 1
Off
On
high
Pre-purge/high-fire rate
BVA
VAG
IC 40
12
26
L1, N, PE
9
18
IN
4
7
5
3
BIO/
BIC
µC
V1
M
mA
DI 1
DI 2
BCU 460..L
4
18
19
16
17
22
P
P
µC
VAG
VAS
PLC