FCU 500, FCU 505 · Edition 02.17
101
Parameters
12 .4 .12 Controller enable signal delay time t
RF
Parameter 44 (only on FCU..F1/F2)
The controller enable signal is delayed by 0, 10, 20 or 30
up to 250 s using parameter 44.
After the furnace control unit has checked the safety
functions, external temperature control can be enabled.
The enable signal can be delayed by up to 250 s using
parameter 44. The FCU displays program status
H8
(safety interlocks enable). After the delay time t
RF
has
elapsed, the FCU signals “Operation” status via the
24 V DC output (terminal 42) and activates the control-
ler enable output (terminal 56).
12 .4 .13 Minimum enable time
Parameter 45
On units with capacity control (FCU..F1/F2), param-
eter 45 can be used to set a minimum enable time (0 to
250 s) for the burner start during which the actuator or
frequency converter stays in the position for minimum
capacity. The minimum enable time must be selected
so that the downstream burners can be started safely.
The burner operating signal (terminal 4) is not evaluated
until the minimum enable time has elapsed if param-
eter 46 = 1.
12 .4 .14 Burner operating signal
Parameter 46
Can only be programmed on FCU..F1 and FCU..F2.
A successful burner start can be reported to the FCU
via the burner operating signal (terminal 4). As soon as
a signal is received at terminal 4 and parameter 46 = 1,
the FCU will issue the controller enable signal.
BCU
V1
BCU
V1
FCU 500..F1
µC
54 55
53
1
67
(BCU..F0)
+24V
L1
M
4
+24V
4
54 55
53
M
Parameter 46 = 0: Off
Parameter 46 = 1: On; controller enable; parameter 47 is
activated.