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 ( 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 one of the digital inputs (must be pro-

grammed 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 con-

nected).

NB!

If Sleep Mode is to be based on No Flow Detection/Minimum Speed, remember to choose Sleep Mode [1] in

Function

Destage at No-Flow

If par. 25-26,

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*

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,

desired reference and feed back signals.

Example: Boost system.

178

, is set for Enabled (see separate

No Flow Detection

MG.11.C5.02 - VLT

VLT

VLT HVAC Drive Programming Guide, MG.11.Cx.yy

Configuration Mode

, must be set for Closed Loop and the PI Controller configured for

is a registered Danfoss trademark