Despatch P1400+ Temperature Controller - Manual (Page 87)

81
Overlap/Deadband Type: Controller Parameter
Defines the portion of the primary and secondary proportional bands (Pb_P + Pb_S ) over which
both outputs are active (Overlap), or neither is active (Deadband). It is adjustable in the range -20%
to +20% of the two proportional bands added together. Positive values = Overlap, negative values =
Deadband.
This parameter is not applicable if the primary output is set for On-Off control or there is no
Secondary Output. If the Secondary Output is set for On-Off, this parameter has the effect of moving
the Differential band of the Secondary Output to create the overlap or deadband. When
Overlap/Deadband = 0, the “OFF” edge of the Secondary Output Differential band coincides with the
point at which the Primary Output = 0%. ).
Display code =
ΟΛ ΟΛ ΟΛ ΟΛ
, default value = 0%.
Also refer to Differential , On-Off Control , Primary Proportional Band and Secondary Proportional
Band .
Figure 37. Overlap/Deadband
Overlap/Deadban
Output 1
Output 1
Output 2
Output 2
Output 2
Process Variable
Process Variable
Process Variable
Proportional Band 1
Proportional
Band 1
Proportional
Band 1
Proportional Band 2
Proportional
Band 2
Proportional Band 2 = 0
Output 1
Output 1
Output 1
Output 1
Output 2
Output 2
Output 2
Overlap
(positive value)
Deadband
(negative value)
Negative values Positive values
OVERLAP WITH
PID
DEADBAND WITH
PID
OVERLAP &
DEADBAND WITH
ON/OFF
O
u
tp
u
t
P
o
w
e
r
(%
)
O
u
tp
u
t
P
o
w
e
r
(%
)
O
u
tp
u
t
P
o
w
e
r
(%
)
O
u
tp
u
t
2
O
N
O
u
tp
u
t
2
O
F
F
ON/OFF Differential