Specifications

State 0
State 1
State 2
Start
command
Stop
command
Event 4 False (0)
Action 4 No Action (1)
Event 1 True (1)
Event 2 On Reference (4)
Event 3 Time Out (30)
Action 3 Select Preset ref. (11
)
Action 2 Start Timer (29)
Action 1 Select Preset (10)
130BA148.11
Illustration 6.6 Set Actions
Set the Smart Logic Control in LC-00 Logic Controller Mode
to ON.
A start/stop command is applied on terminal 18. If stop
signal is applied the frequency converter will ramp down
and go into free mode.
6.1.8 BASIC Cascade Controller
Constant Speed
Pumps (2)
Variable Speed
Pumps (1)
Motor starter
Frequency Converter
with
Cascade Controller
Pressure Sensor
130BA362.10
Illustration 6.7 BASIC Cascade Controller
The BASIC 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 range is not an 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 BASIC 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.
Fixed Lead Pump
The motors must be of equal size. The BASIC cascade
controller allows the frequency converter to control up to
3 equal size pumps using the two built-in relays. When the
variable pump (lead) is connected directly to the drive, the
other 2 pumps are controlled by the 2 built-in relays.
When lead pump alternations is enabled, pumps are
connected to the built-in relays and the frequency
converter is capable of operating 2 pumps.
Lead Pump Alternation
When the motors are of equal size, lead pump alteration
enables the frequency converter to cycle the drive
between the pumps in the system (maximum of 2 pumps).
In this operation, the run time between pumps is
equalized, reducing the required pump maintenance and
increasing reliability and lifetime of the system. The
alternation of the lead pump can take place at a command
signal or at staging (adding another pump).
The command can be a manual alternation or an
alternation event signal. If the alternation event is selected,
Application Examples VLT® HVAC Drive FC 102 Design Guide
158 MG16C102 - Rev. 2013-08-20
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