Additional Configuration For Multiple Drives - Danfoss VLT Series Operating Instructions Manual

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VLT Operating Instructions
Parameter no. Description
27-10 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 reducing
the number of parameters needed to setup 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 shall be used.
To adjust: first choose 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 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.

1.5.2 Additional configuration for Multiple Drives

When more than one frequency converter 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 through a digital signal between the frequency converters.
The master drive must use a digital output pin to output the required frequency for all of the frequency converters. All of the frequency converters 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.
DO DO
Pin 27 Pin 27 Pin 29 Pin 29
Pin 29 Pin 29
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MI.38.C3.02 - VLT is a registered Danfoss trademark
1 Extended and Advanced Cascade Controller
DI DI
DI DI
Option
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