Operating instructions

NOTE
If Sleep Mode is to be based on No Flow Detection/
Minimum Speed, remember to choose Sleep Mode [1] in
par. 22-23 No-Flow Function.
If par. 25-26 Destage At No-Flow 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 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.
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 par. 22-45 Setpoint Boost).
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).
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. Par. 1-00 Configu-
ration Mode must be set for Open Loop.
Example: Boost system.
Parameter Description
VLT
®
HVAC Drive Programming Guide
144 MG.11.CA.02 - VLT
®
is a registered Danfoss trademark
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