Danfoss VLT No Flow Feature Fact sheet

Fact Sheet

VLT® No Flow Feature

The VLT® AQUA Drive provides a new No Flow detection feature for pump systems. This feature is useful for detecting conditions where a pump is producing no ﬂow – a condition that can cause pump damage if not detected and corrected.

No ow based on motor power and frequency

No Flow Detection is based on the measurement of power at speciﬁc motor speeds. The drive monitors actual power and motor frequency and compares it to the calculated no-ﬂow power at speciﬁc speeds. If the power

measured at a speciﬁc frequency is greater than the no-ﬂow power calculated by the drive, the pump is producing ﬂow. If the power measured is less than the no-ﬂow power calculated by the drive, a warning or alarm is generated to notify the operator of the condition.

The perfect solution for

Intelligent control

Water and wastewater system

protection

Remote status reporting

To determine the no-ﬂow power level throughout the speed range, the drive generates a power vs. frequency curve that represents the no-ﬂow condition. This curve is generated by the drive from two data points. These power/ frequency points can be entered into the drive automatically or manually.

Manual or Auto Set Up are available

The Auto Set Up automatically steps the user through the commissioning process, storing the data measured. When the automatic set-up is selected

the output frequencies used are 50% and 85% of maximum. Manual set-up can be used when a diﬀerent pair of frequencies is desired.

Programming is quick and easy

The drive software makes programming the No Flow feature quick and easy by choosing Pump Functions and then No Flow Function under the Quick Menu.

Feature Benet

Eliminates an external diﬀerential pressure switch or ﬂow meter

Eliminates wiring for external sensors Reduce installation and maintenance cost

A warning or alarm can alert operator of the problem

Programming is quick and easy with pre-programmed software

Reduce installation and maintenance cost

Provides proper operation of equipment and increases occupant comfort

Saves time and increases reliablity

www.vlt-drives.danfoss.com

Programming No Flow detection

Programming for No Flow detection is simpliﬁed with a number of para-

Par.# Description

1-00 Conﬁguration mode Open loop VLT® AQUA Drive must be set in Open Loop for Auto Set-up.

22-20 Low Power Auto Set-up Disable Enable Close the outlet valve for the pump before starting Auto Set-up.

The following parameters are accessed through the Main Menu and will be stored after pressing the [OK] key to save the results after the auto-tuning:

22-33 Low Speed

[Hz]

22-34 Low Speed Power [kW] When Low Power Auto Set-up is used, the output power

22-37 High Speed

[Hz]

22-38 High Speed Power [kW ] When Low Power Auto Set-up is used, the output power

1-00 Conﬁguration mode Open loop Closed loop Return the VLT® AQUA Drive to Closed Loop operation if required.

Factory setting

meters that are pre-programmed into the drive. Prior to programming this feature, commission the drive by using

Settings

Recommended setting

Comments

Select Enable and follow the instruction on the LCP. After Auto Set-up is complete, open the pump outlet valve.

When Low Power Auto Set-up is used, 50% of the drive’s maximum frequency will be stored here. This can be manually edited, if desired.

measured under no ﬂow conditions at 50% speed will be stored here. This can be manually edited, if desired.

When Low Power Auto Set-up is used, 85% of the drive’s maximum frequency will be stored here. This can be manually edited, if desired.

measured under no ﬂow conditions at 85% speed will be stored here. This can be manually edited, if desired.

the parameters in the Quick Menu. Then perform the following steps for programming No Flow detection:

These parameters are used after Auto Set-up and the No Flow feature is operating:

22 - 30 No Flow Power When the drive is running, this parameter will show the power

22 - 31 Power Correction Factor 100% 110% This parameter is used to raise or lower the no ﬂow power curve

The following parameters determine the action that the drive will take if a no ﬂow condition is detected:

22-21 Low Power

Detection

22-23 No Flow Function Oﬀ Sleep Mode/Warning/Alarm Select action

22-24 No Flow Delay 10 sec. Set the time delay before the drive will perform the No Flow Function.

The following parameters give an indication to a SCADA system if a no ﬂow condition is detected:

5-40 Function Relay [190] No Flow

Digital Output [190] No Flow

The following are used if No Flow is reported via serial communications:

Protocol Alarm Word Warning Word

Proﬁbus/Proﬁnet Parameter 1691 bit 5=1 Parameter 1693 bit 5=1

DeviceNet/Ethernet IP Class 116, Instance 1, Attribute 193, bit 5=1 Class 116, Instance 1, Attribute 193, bit 5=1

Modbus RTU/TCP Register 16910 Bit 5=1 Register 16930 Bit 5=1

Disable Enable To activate no ﬂow based on power

level that will be interpreted as producing no ﬂow at the current motor speed.

to the percentage entered here. Values above 100% help ensure the drive reliably detects no ﬂow.

Generally set longer than the decel ramp time.

Program one of the relays to selection [190], No Flow. The selected relay will be activated when No Flow occurs.

A digital output can be used to indicate a no ﬂow condition. Use the parameter that sets the function of the desired digital output.

Danfoss Drives, Ulsnaes 1, DK-6300 Graasten, Denmark, Tel. +45 74 88 22 22, Fax +45 74 65 25 80, www.vlt-drives.danfoss.com, E-mail: info@danfoss.com