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 e.g. an electro-mechanical flow
switch to detect a no flow condition and activate Sleep
Mode, the action takes place at raising edge of the
external signal applied (otherwise the frequency converter
would never come out of Sleep Mode again as the signal
would be steady connected).
NOTE
If Sleep Mode is to be based on No Flow Detection/
Minimum Speed, remember to choose Sleep Mode [1] in
.
If
is set for Enabled, activating
Sleep Mode will send 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
Local Control Panel shows Sleep Mode.
See also signal flow chart in
3.20.1 22-2* No-Flow Detection
.
There are three different ways of using the Sleep Mode
function:
130BA255.11
P
f
o
pSL
FC
S
1) Systems where the integrated PI controller is used for
controlling pressure or temperature e.g. boost systems
with a pressure feed back signal applied to the frequency
converter from a pressure transducer.
must be set for Closed Loop and the PI Controller
configured for desired reference and feed back 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
If no flow is detected, the frequency converter will increase
the set point for pressure to ensure a slight over pressure
in the system (boost to be set in
).
The feedback from the pressure transducer is monitored
and when this pressure has dropped with a set percentage
below the normal set point for pressure (Pset), the motor
will ramp up again and pressure will be controlled for
reaching the set value (Pset).
External PID
controller
FC
130BA256.11
P
P
System
P
Set
f
Out
f
Ref
2) In systems where the pressure or temperature is
controlled by an external PI controller, the wake up
conditions can not be based on feedback from the
pressure/temperature transducer as the setpoint is not
known. In the example with a boost system, desired
pressure Pset is not known.
must
be set for Open Loop.
Example: Boost system.
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG.11.CC.02 - VLT
®
is a registered Danfoss trademark
151
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