Main Menu - Cascade Controller - Group - Danfoss VLT Series Programming Manual

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:
Con guration mode (P 1-00):
Cascade controller (P 25-00):
Motor start (P 25-02):
Pump cycling (P 25-04):
Fixed lead pump (P 25-05):
Number of pumps (P 25-06):
Lead pump alternation (P 25-50):
Alternation Event (P 25-51):
Alt. if capacity<50% (P 25-55):
Staging mode at alternation (P 25-56):
®
VLT HVAC Drive Programming Guide
Con g. of cascade controller
Open Loop
Disabled
Direct on line
Disabled
No
2
O
At
staging
Disabled
Slow
®
MG.11.CC.02 - VLT is a registered Danfoss trademark
Closed Loop
Enabled
Soft Starter
Enabled
Yes
2 3
At At staging
or
command
command
Alt. timer
Sleep
External interval
mode
P 25-52
Enabled
Quick
3 3
Prede ned
timer
P 25-54
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