Danfoss VLT HVAC Drive FC 102, Руководство по программированию, Страница: 167 / 250

stops energising the motor. When in sleep mode, certain
conditions are monitored to find out when load has been
applied to the system again.
Sleep mode can be activated either from the no-flow
detection/minimum speed detection (must be
programmed via parameters for no-flow detection, see the
signal flow-diagram in parameter group
22-2*, No-Flow
Detection ) or via an external signal applied to 1 of the
digital inputs (must be programmed via the parameters for
configuration of the digital inputs, parameter group 5-1*
selecting [66] Sleep Mode). Sleep mode is activated only
when no wake-up conditions are present.
To make it possible to use for example an electro-
mechanical flow switch to detect a no-flow condition and
activate Sleep mode, the action takes place at the raising
edge of the external signal applied (otherwise the
frequency converter would stay in sleep mode as the
signal would be steadily connected).
NOTICE
If sleep mode is to be based on no-flow detection/
minimum speed, select
[1] Sleep Mode in
parameter 22-23 No-Flow Function .
If
parameter 25-26 Destage At No-Flow
is set for
[1] Enabled
,
activating sleep mode sends a command to the cascade
controller (if enabled) to start de-staging of lag pumps
(fixed speed) before stopping the lead pump (variable
speed).
When entering sleep mode, the lower status line in the
LCP shows
Sleep Mode .
See also signal flow chart in chapter 3.20.1 22-2* No-Flow
Detection .
There are 3 different ways of using the sleep mode
function:
130BA255.11
P
f
o
pSL
FC
S
Illustration 3.51 Sleep mode function
1) Systems where the integrated PI controller is used for
controlling pressure or temperature for example boost
systems with a pressure feedback signal applied to the
frequency converter from a pressure transducer. Set
parameter 1-00 Configuration Mode for [3] Closed Loop and
configure the PI controller configured for desired reference
and feedback signals.
Example: Boost system.
p (Pressure)
Time
Time
No/Low Flow
detected
P 22-45
P 22-44
Sleep mode
activated
Boost
activated
P
Boost
P
Set
P
Wake
f
Ref
f
out
(Frequency)
P
System
130BA257.10
t
1
p
System
= p
Wake
Illustration 3.52 Boost system
If no-flow is detected, the frequency converter increases
the setpoint for pressure to ensure a slight overpressure in
Parameter Descriptions Programming Guide
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