Danfoss VLT AQUA Drive FC 202 Design Manual

Also see for VLT AQUA Drive FC 202: Service guide Installation guide Installation guide Operating guide Installation guide

Contents

5.8 Flow Confirmation OverviewThe flow confirmation feature is designed for applicationswhere there is a need for the motor/pump to run whilewaiting for an external event. The flow confirmationmonitor expects to receive a digital input from a sensor ona gate valve, flow switch, or a similar external device,indicating that the device is in the open position and flowis possible. In parameter 29-50 Validation Time, define forhow long the VLT® AQUA Drive FC 202 waits for the digitalinput signal from the external device to confirm the flow.After the flow is confirmed, the drive checks the signalagain after the flow verification time and then runsnormally. The LCP status reads Verifying flow while the flowmonitor is active.If the expected digital input signal becomes inactive beforeeither the flow validation time or the flow verification timeexpires, the drive trips with the alarm alarm 92, No flow.130BD766.10N MAXN MIN00110101234t0 t2TTTT1 Speed curve.2 Start command (for example, terminal 18).3 Digital signal from an external device that confirms thatthe flow is possible.4 Flow verification.t0 Start command issued (for example, terminal 18 is setactive).t1 Digital signal from an external device becomes activebefore parameter 29-50 Validation Time expires.t2 When parameter 29-51 Verification Time passes, the drivechecks the signal from the external device again andthen runs normally.Illustration 5.14 Flow ConfirmationParameter andnameDescription Settings UnitParameter 29-50 ValidationTimeThe digital inputmust be activeduring thevalidation time.0.1–999.0(*size dependent)sParameter 29-51 VerificationTimeFlow will beconfirmed if, at theend of the verifi-cation time, thedigital input is stillactive.0.1–255.0(*15)sTable 5.2 Flow Confirmation ParametersNOTICEThe parameters are only visible on the LCP when adigital input is configured as flow confirmation.5.9 Advanced Minimum Speed MonitoringOverviewSome pumps are sensitive to operating at low speed.Insufficient cooling or lubrication at low speed are typicalreasons.Under overload conditions, the drive protects itself usingits integral protection features, which include lowering thespeed. For example, the current limit controller can lowerthe speed. Sometimes, the speed can go lower than thespeed specified in parameter 4-11 Motor Speed Low Limit[RPM] and parameter 4-12 Motor Speed Low Limit [Hz].If the speed drops below a certain value, the advancedminimum-speed monitoring feature trips the drive. If thepump motor does not reach the speed specified inparameter 1-86 Trip Speed Low [RPM] within the timespecified in parameter 1-79 Pump Start Max Time to Trip(ramping up takes too long), the drive trips. Timers forparameter 1-71 Start Delay and parameter 1-79 Pump StartMax Time to Trip start at the same time when the startcommand is issued. For example, if the value inparameter 1-71 Start Delay is more than or equal to thevalue in parameter 1-79 Pump Start Max Time to Trip, thedrive never starts.Product Features Design GuideMG22B102 Danfoss A/S © 05/2017 All rights reserved. 255 5