169
[1.7 APPLICATION FUNCT.]
(FUn-)
Flow limitation
This function can be used to limit the flow of a fluid, in the case of a pump, for example.
The function uses a flow sensor assigned to an analog input, the “pulse in” input or the encoder input. It limits the frequency reference. In the
case of regulation with PID, it affects the PID regulator output reference.
• Before A – The signal on the input assigned to the flow measurement has not reached the activation threshold
[Flow.Lim.Th.Active]
(CHt)
: Flow limitation is not activated and the input reference is applied.
• A – The signal on the input assigned to the flow measurement has reached the threshold
[Flow.Lim.Th.Active]
(CHt)
: Flow limitation
is activated, the reference is limited to
[Low speed]
(LSP)
and the frequency decelerates along the ramp
[Dec. Flow. limit]
(dFL)
.
• B – The signal on the input assigned to the flow measurement has fallen below the hysteresis of the threshold
[Flow.Lim.Th.Active]
(CHt)
: The current frequency is copied and applied as the reference.
• C – The input reference has fallen below the reference B and is continuing to fall: It is applied.
• D – The input reference starts to rise again: The current frequency is copied and applied as the reference.
• E – The signal on the input assigned to the flow measurement has reached the threshold
[Flow.Lim.Th.Active]
(CHt)
: The reference
is limited to
[Low speed]
(LSP)
and the frequency decelerates along the ramp
[Dec. Flow. limit]
(dFL)
.
• F – The signal on the input assigned to the flow measurement has fallen below the hysteresis of the threshold
[Flow.Lim.Th.Active]
(CHt)
: The current frequency is copied and applied as the reference.
• After F – The signal on the input assigned to the flow measurement has fallen below the deactivation threshold
[Flo.Lim.Thres. Inact.]
(rCHt)
: Flow limitation is no longer active and the input reference is applied.
CHt
rCHt
LSP
A
B
E
D
F
C
0
0
0
dFL
dFL
Flow input
Hysteresis for CHt
Hysteresis
Flow limitation active
Frequency reference
Frequency
Ramp
Ramp
Содержание ER40-G
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