Basic Cascade Controller - Danfoss VLT AQUA Drive FC 202 Design Manual

Application Examples
Start/stop command is applied on terminal 18. If the stop signal is applied, the frequency converter ramps down and goes
into free mode.
Start
command
Stop
command
Event 4 False (0)
Action 4 No Action (1)
Illustration 6.6 SLC Application Example

6.1.5 BASIC Cascade Controller

The BASIC Cascade Controller is used for pump
applications where a certain pressure ("head") or level
must be maintained over a wide dynamic range. Running a
large pump at variable speed over a wide range is not an
ideal solution because of low pump efficiency at lower
speed. In a practical way, the limit is 25% of the rated full
load speed for the pump.
In the BASIC Cascade Controller, the frequency converter
controls a variable speed (lead) motor as the variable
speed pump and can stage up to two additional constant
speed pumps on and off. Connect the additional constant
speed pumps directly to mains or via softstarters. By
varying the speed of the initial pump, variable speed
control of the entire system is provided, maintaining
constant pressure while eliminating pressure surges,
resulting in reduced system stress, and quieter operation in
pumping systems.
MG20Z202
Design Guide
Event 1 True (1)
Action 1 Select Preset (10)
State 0
State 2 Event 3 Time Out (30)
Action 3 Select Preset ref. (11)
Danfoss A/S © Rev. 06/2014 All rights reserved.
Event 2 On Reference (4)
Action 2 Start Timer (29)
State 1
Constant Speed
Pumps (2)
Variable Speed
Pumps (1)
Motor starter
Illustration 6.7 BASIC Cascade Controller
Fixed Lead Pump
The motors must be of equal size. The BASIC Cascade
Controller allows the frequency converter to control up to
three equal size pumps using the frequency converter's 2
built-in relays. When the variable pump (lead) is connected
directly to the frequency converter, the 2 built-in relays
control the other two pumps. When lead pump
alternations are enabled, pumps are connected to the
built-in relays and the frequency converter can operate 2
pumps.
Pressure Sensor
Frequency Converter
with
Cascade Controller
143
6 6