Cascade Controller - Danfoss FC 102 Design Manual

Application Examples
Start
command
Stop
command
Event 4 False (0)
Action 4 No Action (1)
Illustration 7.6 Set Event and Action
Set the Smart Logic Control in 13-00 SL Controller Mode to
ON.
Start/stop command is applied on terminal 18. If stop
signal is applied the frequency converter will ramp down
and go into free mode.

7.1.8 Cascade Controller

Constant Speed
Pumps (2)
Variable Speed
Pumps (1)
Motor starter
Illustration 7.7 A Pump Application
The Cascade Controller is used for pump applications
where a certain pressure ("head") or level needs to be
maintained over a wide dynamic range. Running a large
pump at variable speed over a wide for range is not an
MG11BC02
Design Guide
Event 1 True (1)
Action 1 Select Preset (10)
State 0
Event 3 Time Out (30)
State 2
Action 3 Select Preset ref. (11)
Pressure Sensor
Frequency Converter
with
Cascade Controller
Danfoss A/S © Rev. 06/2014 All rights reserved.
Event 2 On Reference (4)
Action 2 Start Timer (29)
State 1
ideal solution because of low pump efficiency and because
there is a practical limit of about 25% rated full load speed
for running a pump.
In the Cascade Controller the frequency converter controls
a variable speed motor as the variable speed pump (lead)
and can stage up to 2 additional constant speed pumps
on and off. By varying the speed of the initial pump,
variable speed control of the entire system is provided.
This maintains constant pressure while eliminating
pressure surges, resulting in reduced system stress and
quieter operation in pumping systems.
Fixed Lead Pump
The motors must be of equal size. The Cascade Controller
allows the frequency converter to control up to 5 equal
size pumps using the frequency converters 2 built-in relays
and terminal 27, 29 (DI/DO). When the variable pump
(lead) is connected directly to the frequency converter, the
other 4 pumps are controlled by the two built-in relays
and terminal 27, 29 (DI/DO). Lead pump alternation cannot
be selected when lead pump is fixed.
Lead Pump Alternation
The motors must be of equal size. This function makes it
possible to cycle the frequency converter between the
pumps in the system (when 25-57 Relays per Pump =1,
maximum pump is 4. When 25-57 Relays per Pump =2,
maximum pump is 3). In this operation, the run time
between pumps is equalized reducing the required pump
maintenance and increasing reliability and lifetime of the
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