Danfoss VLT FC 102 Programming Manual

Also see for VLT HVAC Drive FC 102: Operating instructions Service guide Programming guide Installation guide Installation guide

Contents

NOTICECarry out no-flow tuning before setting the PI controller parameters.FC130BA253.10P130BA254.10HeadFlow21Table 3.25 No-flow DetectionNo-flow detection is based on the measurement of speed and power. For a certain speed, the frequency converter calculatesthe power at no-flow.This coherence is based on the adjustment of 2 sets of speed and associated power at no-flow. Monitoring power enablesdetection of no-flow conditions in systems with fluctuating suction pressure, or of the pump having a flat characteristictowards low speed.The 2 sets of data must be based on measurement of power at approximately 50% and 85% of maximum speed with thevalves closed. The data is programmed in parameter group 22-3* No-Flow Power Tuning. It is also possible to run a [0] LowPower Auto Set Up (parameter 22-20 Low Power Auto Set-up) automatically stepping through the commissioning process andstoring the data measured. Set the frequency converter for [0] Open Loop in parameter 1-00 Configuration Mode, whencarrying out the auto set-up, see parameter group 22-3* No-Flow Power Tuning No-flow Power Tuning.NOTICEIf to use the integrated PI controller, carry out no-flow tuning before setting the PI controller parameters.Low-speed detectionLow-speed detection gives a signal if the motor operates with minimum speed as set in parameter 4-11 Motor Speed LowLimit [RPM] or parameter 4-12 Motor Speed Low Limit [Hz]. Actions are common with no-flow detection (individual selectionnot possible).The use of low-speed detection is not limited to systems with a no-flow situation. Low-speed detection can be used in anysystem where operation at minimum speed allows a stop of the motor until the load calls for a speed higher than minimumspeed. This could, for example, be in systems with fans and compressors.NOTICEIn pump systems, ensure that the minimum speed in parameter 4-11 Motor Speed Low Limit [RPM] orparameter 4-12 Motor Speed Low Limit [Hz] is set high enough for detection as the pump can run with a rather highspeed even with valves closed.Dry-pump detectionIf the pump has run dry (low power consumption-high speed), no-flow detection can also be used for detecting. Can beused with both the integrated PI controller and an external PI controller.Parameter Descriptions Programming GuideM0010001 Danfoss A/S © 10/2019 All rights reserved. 1993 3