Danfoss VLT series User manual

Contents
1 Extended and Advanced Cascade Controller Option
3
How to read these Operating Instructions 3
High Voltage Warning 3
Safety Instructions 3
Avoid unintended Start 3
Software Version 3
Symbols 4
Safety 4
Caution 5
Introduction to MCO 101 and 102 5
Extended Cascade Controller MCO 101 7
Advanced Cascade Controller MCO 102 8
Supported Configurations 10
Extension of Basic Cascade - Parameter group 25** control mode 11
Fixed Speed Pump Configuration 12
Master-Follower Configuration 13
Mixed Pump Configuration 14
Unequal Size Pump Configuration 15
Mixed Pump Configuration with Alternation 17
Soft Starters 18
Configuring the System 18
Setting-up the cascade parameters 18
Additional configuration for Multiple Drives 19
Closed Loop Control 20
Staging / De-staging of variable speed pumps based on Drive Speed 20
Staging / De-staging of fixed speed pumps based on Pressure Feedback 21
Control 21
Cascade Controller Features 21
Pump Status and Control 21
Manual Pump Control 22
Runtime Balancing 22
Pump Spin for unused pumps 23
Total lifetime hours 23
Alternation of the Lead Pump 23
Staging / Destaging in Mixed Pump Configurations 23
Override Staging /Destaging 24
Minimum Speed Destaging 24
Fixed speed only operation 24
Cascade Controller Parameters 25
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Operating Instructions Contents
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Cascade CTL Option, 27-** 25
Control & Status, 27-0* 25
Configuration, 27-1* 26
Bandwidth Settings, 27-2* 27
Staging Speed, 27-3* 30
Staging Settings, 27-4* 31
Alternation Settings, 27-5* 33
Connections, 27-7* 34
Readouts, 27-9* 35
Master/Follower Application Note 38
Index
41
Contents VLT
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Operating Instructions
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1 Extended and Advanced Cascade Controller Option
1.1 How to read these Operating Instructions
1.1.1 High Voltage Warning
The voltage of the frequency converter and the MCO 101 option card is dangerous whenever it is connected to mains. Incorrect
installation of the motor or frequency converter may cause damage to the equipment, serious injury or death. Consequently, it is
essential to comply with the instructions in this manual as well as local and national rules and safety regulations.
1.1.2 Safety Instructions
Prior to using functions directly or indirectly influencing personal safety (e.g. Safe Stop or other functions either forcing the motor to
stop or attempting to keep it functioning) a thorough risk analysis and system test must be carried through. The system tests
must include testing failure modes regarding the control signalling (analog and digital signals and serial communication.
• Make sure the frequency converter is properly connected to earth.
• Do not remove mains connections, motor connections or other power connections while the frequency converter is connected to power.
• Protect users against supply voltage.
• Protect the motor against overloading according to national and local regulations.
• The earth leakage current exceeds 3.5 mA.
• The [OFF] key is not a safety switch. It does not disconnect the frequency converter from mains.
1.1.3 Avoid unintended Start
While the frequency converter is connected to mains, the motor can be started/stopped using digital commands, bus commands, references or via the
Local Control Panel.
• Disconnect the frequency converter and the MCO 101 option card from mains whenever personal safety considerations make it necessary to
avoid unintended start of any motors.
• To avoid unintended start, always activate the [OFF] key before changing parameters.
1.1.4 Software Version
Extended Cascade Controller Option for
VLT AQUA Drive FC 200
Operating Instructions
Software version: 1.33
These Operating Instructions can be used with all Extended Cascade Controller options with software version 1.33.
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NB!
MCO 101/102 is software supported from version 1.24 onwards.
1.1.5 Symbols
When reading through this Operating Instructions, you will come across various symbols that require special attention.
The symbols used are the following:
Indicates a general warning.
NB!
Indicates something to be noted by the reader.
Indicates a high-voltage warning.
1.2 Safety and Caution
1.2.1 Safety
Rotating shafts and electrical equipment can be hazardous. Therefore, it is strongly recommended that all electrical work conform to
National Electrical Code (NEC) and all local regulations. Installation, start-up and maintenance should be performed only by qualified
personnel.
Factory recommended procedures, included in this manual, should be followed. Always disconnect electrical power before working on the unit. Although
shaft couplings or belt drives are generally not furnished by the manufacturer, rotating shafts, couplings and belts must be protected with securely
mounted metal guards that are of sufficient thickness to provide protection against flying particles such as keys, bolts and coupling parts. Even when the
motor is stopped, it should be considered “alive” as long as its controller is energized. Automatic circuits may start the motor at any time. Keep hands
away from the output shaft until the motor has completely stopped and power is disconnected from the controller.
Motor control equipment and electronic controls are connected to hazardous line voltages. When servicing drives and electronic controls, there will be
exposed components at or above line potential. Extreme care should be taken to protect against shock. Stand on an insulating pad and make it a habit
to use only one hand when checking components. Always work with another person in case of an emergency. Disconnect power whenever possible to
check controls or to perform maintenance. Be sure equipment is properly grounded. Wear safety glasses whenever working on electric control or rotating
equipment.
Safety Guidelines
1. The drive must be disconnected from the AC line before any service work is done.
2. The “Stop/Off” key on the of the drive does not disconnect the equipment from the AC line and is not to be used as a safety switch.
3. Correct protective grounding of the equipment must be established. The user must be protected against supply voltage and the motor must be
protected against overload in accordance with applicable national and local regulations.
4. Ground currents are higher than 3 mA.
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Warning against Unintended Start
1. While the drive is connected to the AC line, the motor can be brought to a stop by means of external switch closures, serial bus commands or
references. If personal safety considerations make it necessary to ensure that no unintended start occurs, these stops are not sufficient.
2. During programming of parameters, the motor may start. Be certain that no one is in the area of the motor or driven equipment when changing
parameters.
3. A motor that has been stopped may start unexpectedly if faults occur in the electronics of the drive, or if an overload, a fault in the supply AC
line or a fault in the motor connection or other fault clears.
4. If the “Local/Hand” key is activated, the motor can only be brought to a stop by means of the “Stop/Off” key or an external safety interlock
NB!
It is responsibility of user or person installing drive to provide proper grounding and branch circuit protection for incoming power and
motor overload according to National Electrical Code (NEC) and local codes.
The Electronic Thermal Relay (ETR) in UL listed VLTs provides Class 20 motor overload protection in accordance with NEC in single motor applications,
when par. is set for ETR TRIP 1, ETR TRIP 2, ETR TRIP 3, or ETR TRIP 4, and par. is set for rated motor (nameplate) current.
1.2.2 Caution
The frequency converter DC link capacitors remain charged after power has been disconnected. To avoid an electrical shock hazard,
disconnect the frequency converter from the mains before carrying out maintenance. Wait at least as follows before doing service on
the frequency converter:
Voltage (V) Min. Waiting Time (Minutes)
415 20 30 40
200 - 240 0.25 - 3.7 kW 5.5 - 45 kW
380 - 480 0.37 - 7.5 kW 11 - 90 kW 110 - 250 kW 315 - 1000 kW
525-600 0.75 kW - 7.5 kW 11 - 90 kW 315 - 1200 kW
525-690 11 - 90 kW 45 - 400 kW 450 - 1200 kW
Be aware that there may be high voltage on the DC link even when the LEDs are turned off.
1.3 Introduction to MCO 101 and 102
MCO 101 and 102 are add-on options extending the supported number of pumps and the functionalities of the in-built cascade controller in the VLT®
AQUA Drive.
The extended cascade controller can be used in two different modes.
It can either be used with the extended features controlled by parameter group 27** or it can be used to extend the number of available relays for the
Basic cascade controlled by parameter group 25**.
When one of the cascade options are installed only group 27** will appear. In case the option is supposed to extend the relays in the in-built cascade
controller group 25**, the basic cascade can be enabled in par. 27-10, where after group 25** will be visible in the main menu again. If par. 27-10 is
set to Basic Cascade only, the basic cascade functionality will be available, only extended with 3 relays to a total of 5 relays.
When using group 27** Extended / Advanced Cascade Control, the systems with pump alternation can be set-up with 2 relays per pump, which reduces
the need for external equipment.
With MCO 101, a total of 5 relays can be used for cascade and with MCO 102, a total of 8 pumps can be controlled.
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NB!
If MCO 102 is installed, the relay option MCB 105 can extend the number of relays to 13.
Application
Cascade control is a common control system used to control parallel pumps or fans in an energy efficient way.
The Cascade Controller option provides the capability to control multiple pumps configured in parallel in a way that makes them appear as a single larger
pump.
When using Cascade Controllers, the individual pumps are automatically turned on (staged) and turned off (de-staged) as needed in order to satisfy the
required system output for flow or pressure. The speed of pumps connected to VLT AQUA Drives is also controlled to provide a continuous range of
system output.
Illustration 1.1: Cascade control of multiple pumps
The Cascade Controllers are optional hardware and software components that can be added to the VLT AQUA Drive. It consists of an option board
containing 3 relays that is installed in the B option location on the Drive. Once options are installed the parameters needed to support the Cascade
Controller functions will be available through the control panel in the 27-** parameter group. The Extended Cascade Controller offers more functionality
than the Basic Cascade Controller. It can be used to extend the Basic Cascade with 3 relays and even to 8 relays with the Advanced Cascade Control card
installed.
While the Cascade controller is designed for pumping applications and this document describes the cascade controller for this application, it is also possible
to use the Cascade Controllers for any application requiring multiple motors configured in parallel.
Master/Follower Operation
The Cascade Controller software runs from a single VLT AQUA 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.
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The difference between MCO 101 and MCO 102 is mainly the number of optional relays being made available for the FC. When MCO 102 is installed, the
relays option card MCB 105 may be mounted in the B-slot.
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.
1.3.1 Extended Cascade Controller 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 1.2: Mounting of B-options
Warning Dual supply
NB!
The label MUST be placed on the LCP frame as shown (UL approved).
How to add the MCO 101 option:
• The power to the frequency converter must be disconnected.
• The power to the live part connections on relay terminals must be disconnected.
• Remove the LCP, the terminal cover and the cradle from the FC 202.
• Fit the MCO 101 option in slot B.
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• Connect the control cables and relief the cables by the enclosed cable strips.
• Various systems must not be mixed.
• Fit the extended cradle and terminal cover.
•ReplacetheLCP
• Connect power to the frequency converter.
Wiring the Terminals
Do not combine low voltage parts and PELV systems.
1.3.2 Advanced Cascade Controller MCO 102
The MCO 102 option supports a maximum of 8 pumps and is able to alternate the lead pump with 2 frequency converter relays per pump. This reduces
the need for external auxiliary switches as well as cost of installation.
When MCO 102 (C-option) is used, the number of relays can be increased to a total of 13 by adding the MCB 105 (B-option).
NB!
Before start, interrupt the power supply to the frequency converter. Never install an option card into the frequency converter during
operation.
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
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Illustration 1.3: Enclosure A2, A3 (and B3) 40 mm (only one C option).
Illustration 1.4: Enclosures B (except B3) and C.
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How to add the MCO 102 option:
• The power to the frequency converter must be disconnected.
• The power to the live part connections on relay terminals must be disconnected.
• Remove the LCP, the terminal cover and the cradle from the FC 202.
• Fit the MCO 102 option in slot B.
• Connect the control cables and relief the cables by the enclosed cable strips.
• Various systems must not be mixed.
• Fit the extended cradle and terminal cover.
•ReplacetheLCP
• Connect power to the frequency converter.
The VLT Advanced Cascade Control Card MCO 102 option is exclusively intended for use in option slot C1. The mounting position of C1 options is shown
in the drawing below.
Wiring the Terminals:
8 relays 7 digital inputs
Table 1.1: Advanced Cascade Controller MCO 102 terminal connections
Some items are needed for the installation of a C-option mounting kit (depending on the enclosure):
Type Description Ordering number
Options:
MCF 105 Mounting Kit frame size A2 and A3 (40mm for one C
Option) 130B7530
MCF 105 Mounting Kit Frame size A5 130B7532
MCF 105 Mounting Kit Frame size B,C,D,E ,F1 and F3 (Except B3) 130B7533
MCF 105 Mounting Kit frame size B3 (40mm for one C Option) 130B1413
Accessory Bag:
MCO 102 Accessory Bag 130B0152
1.4 Supported Configurations
The Extended- and Advanced Cascade Controller support a variety of different pump and Drive configurations. All of these configurations must have at
least one variable speed pump, controlled by a VLT AQUA Drive, with the Extended- and Advanced Cascade Controller option card installed. They support
from 1 to 8 additional pumps each connected to either a Danfoss VLT Drive with Master / Follower or to mains through a contactor or soft starter for a
direct online system.
When setting-up the system, it is necessary to create a hardware configuration, which communicate to the Master, how many pumps and drives are
connected. The necessary hardware is explained in the following hardware configuration examples.
The following describes the features and how to use the extended cascade by means of parameters in group 27:
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1.4.1 Extension of Basic Cascade - Parameter group 25** control mode
Use of the extended cascade option MCO 101 as an extension of the built-in basic cascade in the drive
In applicationsalready controlled bythe built-in cascadecontroller in group 25**, the option card can be used to extend the numbers of relays for cascade
control. For instance if a new pump is added to the system. It can also be used in case it is wanted to alternate the lead pump in systems with more than
2 drives, which is the limit for the basic cascade without MCO 101 option installed.
Install the option in slot B, enable the Basic cascade in par. 27-10. Please refer to AQUA programming guide for parameter group 25** settings.
Example: Electrical wiring diagram for the external equipment needed for systems with alternating lead pump of 4 pumps using Basic cascade and MCO
101 as relay extension.
Illustration 1.5: Control circuit alternating lead pump (4 pumps).
Illustration 1.6: Mains circuit alternating lead pump (4 pumps).
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1.4.2 Fixed Speed Pump Configuration
In this configuration a single Drive controls one variable speed pump and up to 7 fixed speed pumps. The fixed speed pumps are staged and de-staged
as needed through contactors direct online. The single pump connected to the Drive provides the finer level of control needed between the stages.
The direct online pumps are staged or de-staged depending on the feedback.
Illustration 1.7: Example
For this configuration relay selections in Group 27-7* “Connections” are as follows:
27-70 RELAY 1 →[73] Pump 2 to Mains
27-71 RELAY 2 →[74] Pump 3 to Mains
27-72 RELAY 10 →[75] Pump 4 to Mains
27-73 RELAY 11→[0] Standard Relay
27-74 RELAY 12→[0] Standard Relay
The Fixed Speed Pump configuration provides a cost effective method for controlling up to 6 pumps. It is able to control system output by controlling the
number of running pumps as well as the speed of the single variable speed pump. It will however produce wider pressure fluctuations during staging/
destaging transitions and it may be less energy efficient than the Master-Follower configurations.
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1.4.3 Master-Follower Configuration
In this configuration each pump is controlled by a frequency converter. All of the pumps and frequency converters must be of the same size. Staging and
de-staging decisions are made based on the speed of the frequency converters. The constant pressure is controlled by the master drive operating in
closed loop. The speed will be the same in all running pumps with extended control. Up to 6 pumps can be controlled (with Advanced Control up to 8
pumps).
In the Master/Follower mode, MCO 101 supports up to 6 pumps - MCO 102 up to 8 pumps. Please see
Master/Follower Operation Application for FC
200
(Annex A) for further details.
Illustration 1.8: Example
For this configuration relay selections in Group 27-7* “Connections” are as follows:
27-70 RELAY 1 →[1] Drive 2 Enable
27-71 RELAY 2 →[2] Drive 3 Enable
27-72 RELAY 10→[3] Drive 4 Enable
27-73 RELAY 11→[0] Standard Relay
27-74 RELAY 12→[0] Standard Relay
The master-follower configuration provides the gentlest transition from one stage to the next and the most energy efficient operation. For most installations
the energy savings make this the most cost effective configuration.
The system will automatically runtime balance all pumps depending on the pump prioritization made in par. 27-16. The Master/Follower system will
provide a certain level of redundancy. If the master drive trips, it will continue to control the follower drives.
MCB-107 External 24 VDC power supply can be added to increase the level of redundancy.
Furthermore it reduces wear and tear on pumps and motors. The relays set to [0] Std. Relay, can be used as general purpose relays, controlled by the
parameters in group 5-4*.
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1.4.4 Mixed Pump Configuration
The Mixed Pump configuration supports a mix of variable speed pumps connected to Drives as well as additional fixed speed pumps. In this configuration
all of the variable speed pumps and Drives must be the same size. The fixed speed pumps may be of different sizes. The variable speed pumps are staged
on and staged off first based on Drive speed. The fixed speed pumps are then staged on last and staged off last based on the feedback pressure.
Illustration 1.9: Example
For this configuration relay selections in Group 27-7* “Connections” are as follows:
27-70 RELAY 1 →[1] Drive 2 Enable
27-71 RELAY 2 →[74] Pump 3 to Mains
27-72 RELAY 10→[75] Pump 4 to Mains
27-73 RELAY 11→[0] Standard Relay
27-74 RELAY 12→[0] Standard Relay
This configuration provides some of the benefits of the Master Follower configuration with some of the initial cost savingsof the Fixed Speed configuration.
It is a good choice when the extra capacity of the fixed pumps is rarely needed.
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1.4.5 Unequal Size Pump Configuration
The Unequal Size Pump configuration supports a limited mix of fixed speed pumps in different sizes. It provides for the largest range of system output
with the smallest number of pumps.
Illustration 1.10: Example
For this configuration relay selections in Group 27-7* “Connections” are as follows:
27-70 RELAY 1 →[73] Pump 2 to Mains
27-71 RELAY 2 →[74] Pump 3 to Mains
27-72 RELAY 10 →[75] Pump 4 to Mains
27-73 RELAY 11→[0] Standard Relay
27-74 RELAY 12→[0] Standard Relay
Not all configurations of unequal size pumps are valid. For a configuration to be valid it must be possible to stage pumps in increments of 100% of the
size of the Master Drive’s variable speed pump. This is necessary since the variable speed pump must be able to control the output between the fixed
speed stages.
Valid Configurations
100% is defined as the maximum flow produced by the pump connected to the Master Drive. The fixed speed pumps must be multiples of this size.
Variable Speed Fixed Speed
100% 100% + 200%
100% 100% + 200% + 200%
100% 100% + 100% + 300%
100% 100% + 100% + 300% + 300%
100% 100% + 200% + 400%
100% + 100% 200%
100% + 100% 200% + 200%
(Other valid configurations are possible)
Invalid Configurations
Invalid configurations will still run but will not stage on all of the pumps. This is done to allow for limited operation if a pump fails or is interlocked in this
configuration.
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Variable Speed Fixed Speed
100% 200% (no control between 100% and 200%)
100% 100% + 300% (no control between 200% and 300%)
100% 100% + 200% + 600% (no control between 400% and 600%)
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1.4.6 Mixed Pump Configuration with Alternation
In this configuration is possible to alternate the Drive between two pumps along with controlling additional fixed speed pumps. The cascade controller
will attempt to balance the running hours between all of the pumps as specified by the Runtime Balancing parameter.
Illustration 1.11: Example 1
The two pumps can be ether variable speed or fixed speed with equal running hours.
For this configuration relay selections in Group 27-7* “Connections” are as follows:
27-70 RELAY 1 →[8] Pump 1 to Drive 1
27-71 RELAY 2 →[16] Pump 2 to Drive 1
27-72 RELAY 10 →[72] Pump 1 to Mains
27-73 RELAY 11 →[73] Pump 2 to Mains
27-74 RELAY 12→[0] Standard Relay
Illustration 1.12: Example 2
The first two pumps can be either variable speed or fixed speed with equal running hours between all three pumps as long as the system demand is
typically greater than 1 pump.
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For this configuration relay selections in Group 27-7* “Connections” are as follows:
27-70 RELAY 1→[8] Pump 1 to Drive 1
27-71 RELAY 2→→[16] Pump 2 to Drive 1
27-72 RELAY 10 →[72] Pump 1 to Mains
27-73 RELAY 11 →[73] Pump 2 to Mains
27-74 RELAY 12 →[74] Pump 3 to Mains
Illustration 1.13: Example 3
The first two pumps alternate each with 50% of the running hours. The fixed speed pumps turned on and off as needed with equal running time between
them.
For this configuration relay selections in Group 27-7* “Connections” are as follows:
27-70 RELAY 1 →[8] Pump 1 to Drive 1
27-71 RELAY 2 →[16] Pump 2 to Drive 1
27-72 RELAY 10 →[74] Pump 3 to Mains
27-73 RELAY 11 →[75] Pump 4 to Mains
27-74 RELAY 12 →[76] Pump 5 to Mains
1.4.7 Soft Starters
Soft Starters can be used in place of contactors for any configuration using fixed speed pumps. If Soft Starters are selected, they must be used for ALL
fixed speed pumps. Mixing Soft Starters and contactors will result in an inability to control the output pressure during staging and de-staging transitions.
When using soft-starters a delay will be added from staging signal occurs until staging takes place. The delay is necessary due to the ramp time of the
fixed speed pump because of the soft-starter.
1.5 Configuring the System
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 frequency converters and pumps in the system and to describe the desired level of control of the systems output.
1.5.1 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.
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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
Pin 27
DI
DI
Pin 29
Pin 29
DO
Pin 27
DI
DI
Pin 29
Pin 29
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1.5.3 Closed Loop Control
The master drive is the primary controller for the system. It monitors the output pressure, adjusts the speed of the frequency converters and decides
when to add or remove stages. To perform this function the master drive must be setup in closed loop mode with a feedback sensor connected to an
analog input of the Drive.
The PID controller of the master drive must be setup to match the needs of the installation. Setting up the PID parameters is described in the
VLT AQUA
Drive Programming Guide
and will not be covered in this manual. Please see also application note Master/Follower Operation, included in this manual.
1.5.4 Staging / De-staging of variable speed pumps based on Drive Speed
In Master-Follower configurations and Mixed Pump configurations the variable speed pumps are staged and de-staged based on the speed of the Drives.
Staging occurs when the speed of the Drives has reached the value in parameter 27-31 (27-32) Stage on Speed. At this speed the system pressure is
still maintained but the pumps are beginning to operate outside of their peak efficiency points. Staging on an additional pump will lower the speed of all
of the running pumps and provide a more energy efficient operation.
De-staging occurs when the speed of the Drives drops below the value in parameter 27-33 (27-34) Stage Off Speed. At this speed the system pressure
is still maintained but the pumps are beginning to operate below their peak efficiency points. De-staging a pump will cause the speed of the Drives to
increase into a more energy efficient range.
Parameters 27-31 (27-32) Stage on Speed and 27-33 (27-34) Stage Off Speed are installation dependent. These parameters are indexed parameters
with one set of entries for each pump stage.
The stage on and de-stage off speed can be auto tuned during automation or set manually. If Auto-tune is enabled the system will start operation using
default settings or the pre settings done by the user in P27-31 (27-32) and 27-33 (27-34) before enabling the auto-tune.
The goal is to find the stage on and off speeds where the system is most energy efficient. See drawing below.
Illustration 1.14: Staging:
A: Wrong adjusted stage on speed
B: Correct adjusted stage on speed
C: Stage on speed pump 2
When the system is set in operation it will monitor the actual energy consumption and fine adjust every time a stage or de-stage takes place.
This feature will over time ensure the most energy efficient way of operation taking into account wear and tear of the pump system.
Danfoss has available the Multiple Unit Staging Efficiency Calculator (MUSEC), a free software program available on the Danfoss web site. By entering
pump and system data, MUSEC provides the optimal settings for the Stage on Speed and Stage off Speed parameters.
1 Extended and Advanced Cascade Controller
Option VLT
®
Operating Instructions
20 MI.38.C3.02 - VLT®is a registered Danfoss trademark
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