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VLT® HVAC Drive Programming Guide
Parameter Description
3.23 Main Menu - Cascade Controller - Group 25
Parameters for configuring the Basic Cascade Controller for sequence control of multiple pumps. For a more application
oriented description and wiring examples, see Chapter Application Examples, item Basic Cascade Controller in the Design
Guide, MG20NXYY.
To configure the Cascade Controller to the actual system and the desired control strategy, it is recommended to follow the
below sequence, starting with parameter group 25-0* System Settings and next parameter group 25-5* Alternation Settings.
These parameter can normally be set in advance.
Parameters in 25-2* Bandwidth Settings and 25-4* Staging settings, will often be dependent on the dynamic of the system
and final adjustment to be done at the commissioning of the plant.
NOTE
The Cascade Controller is supposed to operate in closed loop controlled by the built-in PI controller (Closed Loop selected
in 1-00 Configuration Mode). If Open Loop is selected in 1-00 Configuration Mode, all fixed speed pumps will be destaged, but
the variable speed pump will still be controlled by the frequency converter, now as an open loop configuration:
Configuration mode (P 1-00):
Open Loop
Closed Loop
Cascade controller (P 25-00):
Disabled
Enabled
Direct on line
Motor start (P 25-02):
Pump cycling (P 25-04):
130BA279.12
Config. of cascade controller
Soft Starter
Disabled
Enabled
Fixed lead pump (P 25-05):
No
Yes
Number of pumps (P 25-06):
2
Lead pump alternation (P 25-50):
Off
At
staging
Alternation Event (P 25-51):
2
At
command
External
Alt. if capacity<50% (P 25-55):
Staging mode at alternation (P 25-56):
3
At staging
or
command
Alt. timer
interval
P 25-52
Disabled
Enabled
Slow
Quick
MG11CD02 - VLT® is a registered Danfoss trademark
Sleep
mode
Predefined
timer
P 25-54
175
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