2.19.3. 22-4* Sleep Mode
If the load on the system allows for stop of the motor and the load is monitored, the motor can
be stopped by activating the Sleep Mode function. This is not a normal Stop command, but ramps
the motor down to 0 RPM and stops energizing 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 or via
an external signal applied to one of the digital inputs (must be programmed via the parameters
for configuration of the digital inputs, par.5-1* selecting Sleep Mode).
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).
If par. 25-26,
Destage at No-Flow
, is set for Enabled activating Sleep Mode will apply a command
to the cascade controller (if enabled) to start destaging 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 section 22-2*
No Flow Detection
.
There are three different ways of using the Sleep Mode function:
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. Par. 1-00,
Configuration Mode
, must be set for Closed Loop and the PI Controller
configured for desired reference and feed back signals.
Example: Boost system.
VLT
®
AQUA Drive Programming Guide
2. Parameter Description
MG.20.O2.02 - VLT
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is a registered Danfoss trademark
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