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3.6.11 General Description
The Cascade Controller software runs from a single VLT Automation VT Drive with the Cascade Controller option card installed. This frequency converter
is referred to as the Master Drive. It controls a set of pumps each controlled by a frequency converter or connected directly to mains through a contactor
or through a soft starter.
Each additional frequency converter in the system is referred to as a Follower Drive. These frequency converters do not need the Cascade Controller
option card installed. They are operated in open loop mode and receive their speed reference from the Master Drive. The pumps connected to these
frequency converters are referred to as Variable Speed Pumps.
Each additional pump connected to mains through a contactor or through a soft starter is referred to as a Fixed Speed Pump.
Each pump, variable speed or fixed speed, is controlled by a relay in the Master Drive. The frequency converter with the Cascade Controller option card
installed has five relays available for controlling pumps. Two (2) relays are standard in the FC and additional 3 relays are found on the option card MCO
101 or 8 relays and 7 digital inputs on option card MCO 102.
The Cascade Controller is capable of controlling a mix of variable speed and fixed speed pumps. Possible configurations are described in more detail in
the next section. For simplicity of description within this manual, Pressure and Flow will be used to describe the variable output of the set of pumps
controlled by the cascade controller.
3.6.12 Extended Cascade Control MCO 101
The MCO 101 option includes 3 pieces of change-over contacts and can be fitted into option slot B.
Electrical Data:
Max terminal load (AC)
240 V AC 2A
Max terminal load (DC)
24 V DC 1 A
Min terminal load (DC)
5 V 10 mA
Max switching rate at rated load/min load
6 min
-1
/20 sec
-1
Illustration 3.25: Mounting of B-options
Automation VT Drive FC322 Design Guide
3 VLT Automation VT Drive Selection
MG.20.X1.22 - VLT
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is a registered Danfoss trademark
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