Configuring The System; Introduction; Setting Up The Cascade Parameters; Additional Configuration For Multiple Drives - Danfoss MCO 101 Manual

Extended and Advanced Cascade Controller
Option

4 Configuring the System

4.1.1 Introduction

The extended and advanced cascade controller can be quickly configured using many of the default parameters. However, it is first necessary to describe
the configuration of the adjustable frequency drives and pumps in the system, and to describe the desired level of control of the system's output.

4.1.2 Setting up the cascade parameters

Parameter groups 27-1* "Configuration" and 27-7* "Connections" are used to define the hardware configuration of the installation. Start the configuration
of the cascade controller by selecting values for the parameters in the 27-1* "Configuration" group.
Parameter no. Description
27-10 The cascade controller can be used to enable or disable the extended cascade controller. The Mixed Pump selection is the
general selection for the cascade controller. If using one drive per pump, the master/follower configuration can be selected
to reduce the number of parameters needed to set up the system.
27-11 Number of Drives
27-12 Number of Pumps - Will default to the Number of Drives.
27-14 Pump Capacity for each pump (Indexed Parameter) - If all of the pumps are the same size, the default values are to be used.
To adjust: first, choose the pump, click OK, and adjust the capacity.
27-16 Runtime Balancing for each pump (Indexed Parameter) - If the system should equally balance the running hours between
the pumps, then use the default values.
27-17 Motor Starters - all fixed speed pumps must be the same.
27-18 Spin Time for Unused Pumps - Depends on the size of the pumps.
Next, the relays used to turn pumps on and off need to be defined. Parameter group 27-7* "Connections" provides a list of all of the
available relays:
• Each follower drive in the system needs to have one relay assigned to enable/disable the drive as needed.
• Each fixed speed pump needs to have one relay assigned to control the contactor or enable the soft starter to turn the pump on/off.
• If it is necessary to have a single drive alternate between two pumps, then additional relays need to be assigned to provide this capability.
Any unused relays will be available for other functions through the parameter group 5-4* Relays.

4.1.3 Additional Configuration for Multiple Drives

When more than one adjustable frequency drive is used in the cascade controller, it is necessary for the Master Drive to tell the Follower Drives how fast
to run. This is accomplished using a digital signal between the adjustable frequency drives.
The master drive must use a digital output pin to output the required frequency for all of the adjustable frequency drives. All of the adjustable frequency
drives always run at the same speed. Par. 5-01 is set to [Output], par. 5-30 to [Pulse output] and par. 5-60 to [Cascade ref.].
Each of the follower drives must then be set to open-loop and must use a digital input as their speed reference. This can be done by setting par. 1-00
Configuration Mode to [0] Open-loop and par. 3-15 to selection [7] Frequency Input 29 and par. 5-13 to [32] Pulse input.
The 3-41 Ramp-up Time and 3-42 Ramp-down Time must be the same for the master drive and for all of the follower drives in the system.
These ramps should be set fast enough to enable the PID controller to maintain control of the system.
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MI.38.C2.22 - VLT is a registered Danfoss trademark
4 Configuring the System
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