Sulzer ABS PC 441 - Speed Controlled Pumps (VFD); Configure Pc 441 For Vfd Pump(S)

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3.6 Speed controlled pumps (VFD)
PC441cancontrolpumpsconnectedtoVFDintwoways,bytheAnalogoutputsorbytheoptionalRS-485
moduleCA622.ThemoduleCA622o󰀨ersalotofadvantagesoverrunningtheVFDbyuseoftheanalog
signals.Theinstallationtimeandcostwillbereducedandtheaccuracyinpumpcalculationswillincrease.
To control the pumps from the analog outputs
PC441mainunitcancontrolmaxtwopumpsonVFDbecausethereareonlytwoanalogoutputsonthe
PC441.WiththeexpansionunitCA781comestwoadditionalanalogoutputswhichmakeitpossibletocontrol
twoextraVFDpumps,fourpumpsintotal,atthesametime.
VFDpumpsaremainlycontrolledbystart/stoplevelandthedigitaloutputslikexedspeedpumps.Theanalog
outputsignalscontrolthespeedintheVFDunit(s)whichdrivesthepumps.Normalstartandstoplevelsare
usedtostartandstoptheVFDpump(s).
Thebuilt-inPIDcontrollerisusedaccordingtotheconstantlevelcontrolmethodandoutputsfrequencyset
pointstotheVFD.ThePIDcontrollerwillraisethefrequencywhenthewaterlevelrisesabovethesetleveland
lowerthefrequencywhenthewaterlevelfallsbelowthesetlevel.Insomecases,thecontrollogicwilloverride
theoutputsignalfromthePIDcontroller.
To control the pumps via the CA 622 module
CA622communicatewiththeVFDsbyRS485eldbus.TheCA622unitisconnectedtothesystemvia
CANbus.CA622isttedwithagalvanicallyisolatedRS485communicationportforcommunicationwith
peripheralproductssuchVFDs,softstartersandenergymeters.CA622isalwaystheModbusmasterwithall
peripherals acting as Modbus slaves.
PC441hasmanypredenedVFDs,thecorrectonemustbechoseninthemenus.AllthepredenedVFDs
areoptionsinthermwareofPC441andCA622.IfyoucannotndyourbrandandmodelofVFD;makesure
thatyouhavethelatestrmwareversioninPC441andinCA622.OnSulzerhomepageyoucanndthe
Installation and user guide CA 622(P/N81307133)thereyoucanseeifyourmodelofVFDissupported.
ConguretheCA622moduleinPC441under–Settings–communication–Fieldbusunits–CA622–YES
Atstartlevelthepumpwillstartatmaxfrequency,ifthestartlevelishigherthansetpoint.Outputsignaliskept
atmaxfreq.untilthesetlevelisreached.Ifcalculationofpumpcapacityisenabledthepumpwillrunatmax
frequency,untilthecalculationiscompleted.Ifthepumpisrunningatminfrequencyforanadjustabletimeyou
can set a force speed for pumping out the pit. The pump will go on force speed until stop level is reached (or
set level).
Ifthepumpisexercised,thepumpwillrunonmaxfrequency.WhenreversingthepumpthespeciedReverse
Speedvaluewillbeused(50%default).Inhightari󰀨pre-pumpdownmodethepumpwillrunonthesame
forcespeedasspeciedforminfreq.timeout.
IfthereismorethanonepumpconnectedtoVFD,thepumpswillbesynchronized.Theoutputsignalswill
alwaysbethesameifthescalingisthesame.TheVFDisresponsibleforspeedingupandslowingdownthe
pump.PC441doesn’thandleramptimes.Theminandmaxfrequencyforthepumpnormallyissetonthe
VFD.
ThePIDControlleralsohasadjustableminandmaxvaluefortheoutputsignalthatcanbeused.
ThereisapossibilitytorunVFDpumpswithtwodi󰀨erentSet Points,connectedtodayandnightsettings.
PIDoperatorsettingsarefoundunderStatus:Status / PID controller.
3.6.1 CongurePC441forVFDpump(s)
• In Settings / Pump xmenu:SetType of pump to [Speed controlled VFD]
IfasecondVFDpumpisused.Setthesametypeforthat.
• Onthenextlevelinthemenu,[Pcap comp. at min Freq](Pumpcapacityatminimumfrequency),
thepumpcapacityisalwayscalculatedwhenthepumpisrunningatmaxspeed.Whenthepumpis
atlowerspeedthecapacitywillbelower.Enterthecompensationforthathere.
Settingthisparameterto50%meansthatthecapacityatminspeed(freq.)ishalfofthemaxspeed
capacity.
NOTE! Thisisimportantforoutowandpumpedvolumecalculation.
• In Settings / Pump xmenu:Setthestart and stoplevelforthepump,thestartlevelshouldbe
higherthanthesetlevelonthePIDcontroller.Thestoplevelshouldbelowerthanthesetlevel.
• In Settings / Analog outputs / Analog output 1menu:
Set Output function to [PID controller].
ThesameforAnalogoutput2,ifasecondVFDpumpisused,theoutputshouldbeconnectedtothe
frequencyinputontheVFD
• In Settings / Digital outputs; Set output function [Pump relay]asforxedpumps.Theoutputshould
beconnectedtothe“Run input”ontheVFD.