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BCU 460, BCU 465 · Edition 11.19
114
Parameters
11 .16 Functions of inputs at terminals 1 to 7
and 35 to 41
The BCU has multiple physical and logical interfaces
to receive its input signals and set output signals. Pa-
rameters I061 to I074 are used to define which input
signals can be received at the various terminals (1 to 7
and 35 to 41).
Sensors (pressure switches and POC switches) can be
connected to inputs 36, 37 and 38 depending on the
parameter setting.
BCU . .E0
Input 35 is reserved for the safety interlock function. All
other inputs can also be parameterized for the safety
interlock function (I061 = 4).
11 .16 .1 Function of input 1
Parameter I061
To define the input signal for terminal 1.
Parameter I061 = 0: Off. The input has no function.
Parameter I061 = 4: safety interlocks. The “safety inter-
locks” signal can be applied via the input and/or Safe-
tyLink. No start-up is commenced if there is no signal at
the input. If the signal drops out during operation, the
gas valves are closed immediately (< 1 s).
Parameter I061 = 5: air. The BCU receives the signal for
controlled air flow or for external air actuator control
through the input.
Parameter I061 = 6: cooling air. The BCU receives the
signal to actuate the cooling air actuator through the
input.
Parameter I061 = 7: air actuator R1. The BCU receives
the feedback signal for the ignition position from actua-
tor IC 40 through the input.
Parameter I061 = 8: air actuator R2. The BCU receives
the feedback signal for the High position from actuator
IC 40 through the input.
Parameter I061 = 9: start 1. The BCU receives the start-
up signal (start 1) through the input.
Parameter I061 = 11: reset. The BCU receives the signal
for a remote reset through the input.
Parameter I061 = 12: purge. The BCU receives the
purge signal through the input.
Parameter I061 = 13: LDS start-up conditions. The BCU
does not perform a burner start-up, restart or start-up
attempt until the central actuator is in ignition position,
see the application example on page 18 (Modulating
burner control). To ensure that the burners only start
with the start fuel flow rate, the higher-level control
system sends a signal to start the burner through the
terminal to the BCU.
Parameter I061 = 14: high temperature operation. This
input is used to signal to the burner control unit that the
furnace system is in High temperature mode (HT). The
burner control unit switches to High temperature mode
when the HT input is activated. It operates without eval-
uating the flame signal and its internal flame control
system is non-functional.