Honeywell W7750A specifications Appendix B. Sequences of Operation

Page 52

EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER

Occasionally, the PID parameters require tuning to optimize comfort and smooth equipment operation. This applies to the W7750A,B,C Controllers.

CVAHU Controllers are configured by E-Vision with default values of PID parameters as shown in Appendix C Table 21. If different values for these parameters are desired, Table 13

lists some recommended values to use as a starting point. These recommended values are based on past experience with the applications and in most cases do not require further adjustment.

Table 13. Recommended Values For PID Parameters.

 

 

 

 

 

 

 

 

 

 

 

Heat

Heat

Heat

Heat

Cool

Cool

Cool

Cool

Econ

 

Prop.

Integ.

Deriv.

Control

Prop.

Integ.

Deriv.

Control

Control

Equipment Configuration

Gain

Gain

Gain

Band

Gain

Gain

Gain

Band

Band

 

 

 

 

 

 

 

 

 

 

Single Stage

2

3000

0

10

2

3000

0

10

10

 

 

 

 

 

 

 

 

 

 

Two Stages

3

2000

0

10

3

2000

0

10

10

 

 

 

 

 

 

 

 

 

 

Three Stages

4.5

1500

0

10

4.5

1500

0

10

10

 

 

 

 

 

 

 

 

 

 

Four Stages

6

1000

0

10

6

1000

0

10

10

 

 

 

 

 

 

 

 

 

 

Series 60 Modulating (Floating)

2

750

0

10

2

750

0

10

10

 

 

 

 

 

 

 

 

 

 

PWM Modulating

2

900

0

10

2

900

0

10

10

 

 

 

 

 

 

 

 

 

 

If the PID parameters require adjustment away from these values, use caution to ensure that equipment problems do not arise (see CAUTION below). If any change to PID control parameters is made, the adjustments should be gradual. After each change, the system should be allowed to stabilize so the effects of the change can be accurately observed. Then further refinements can made, as needed, until the system is operating as desired.

CAUTION

If large or frequent changes to PID control parameters are made, it is possible to cause equipment problems such as short cycling compressors (if the stage minimum run times were disabled in User Addresses DisMinClTime or DisMinHtTime). Other problems that can occur include wide swings in space temperature and excessive overdriving of modulating outputs.

If adjustment of PID parameters is required, use the following. In the items that follow, the term, error, refers to the difference between the measured space temperature and the current actual space temperature setpoint.

—The Proportional Gain (also called Throttling Range) determines how much impact the error has on the output signal. Decreasing the Proportional Gain amplifies the effect of the error; that is, for a given error, a small Proportional Gain causes a higher output signal value.

—The Integral Gain (also called Integral Time) determines how much impact the error-over-time has on the output signal. Error-over-time has two components making up its value: the amount of time the error exists; and the size of the error. The higher the Integral Gain, the slower the control response. In other words, a decrease in Integral Gain causes a more rapid response in the output signal.

—The Derivative Gain (also called Derivative Time) determines how much impact the error rate has on the output signal. The error rate is how fast the error value is changing. It can also be the direction the space temperature is going, either toward or away from the setpoint, and its speed— quickly or slowly. A decrease in Derivative Gain causes a given error rate to have a larger effect on the output signal.

—The Control Band is used only for discharge temperature control of modulating outputs, which includes controlling the economizer dampers, and heating and cooling valves using Cascade Control. The Control Band dictates the span through which the discharge temperature must travel to cause the output signal to go from fully closed to fully open. Also, 10 percent of the Control Band value is the size of the deadband around the setpoint where no actuator motion occurs. For example, if controlling a cooling valve with Cascade Control enabled and with the discharge temperature within 0.1 X DaTempClCtrlBd of the discharge setpoint, there is no change in the current valve position. The smaller the Control Band, the more responsive the control output. A larger Control Band causes more sluggish control. Be careful not to set the Control Band too low and cause large over or under shoots (hunting). This can happen if the space or discharge sensors or wiring are in noisy environments and the value reported to the controller is not stable (such that it bounces). The Control Band is used only in modulating control, and has no purpose when staged control is configured.

Appendix B. Sequences of Operation.

This Appendix provides the control sequences of operation for the models of the Excel 10 W7750 CVAHU Controller. The W7750A,B,C Controllers can be configured to control a wide variety of possible equipment arrangements. Table 14 and 15 (copied from Tables 3 and 4) summarize the available options. This Appendix provides a more detailed discussion of these options.

74-2958— 1

52

Page 51 Page 53
Image 52
Page 51 Page 53
Contents Excel Appendices General Considerations W7750 Controllers72-2958 List of Figures 74-2958Setpoint ramping parameters with ramp rate calculation 74-2958List of Tables Description of Devices Typical system overviewControl Application Control ProvidedProducts Covered Organization of ManualApplicable Literature Form No TitleProduct Names Agency ListingsAbbreviations and Definitions Construction ControllersW7750A DI-1Power Performance SpecificationsSpecial Note for the W7750B,C Unit CPU Specified Space Temperature Sensing RangeMemory Capacity Excel 10 W7750C Constant Volume AHU Controller Jack DIN rail adapters Lonmark Functional ProfileInputs/Outputs Analog InputsTriac Outputs on the W7750B,C Models only Digital InputsDigital Outputs Wall Modules Duct SensorT7770A1006 T7770CT7560A,B construction in in. mm Configurations GeneralConfiguration Options Summary For W7750A,B,C Controllers Allowable Heating and Cooling Equipment Configurations Staged HEATING/COOLING ControlHeat Pump Control Modulating HEATING/COOLING ControlEconomizer Control Pneumatic Actuator ControlOccupancy Sensor Window Open/Closed Digital InputWall Module Options MIXED-OUTPUT-TYPE ControlModes of Operation Dirty Filter MonitorIndoor Air Quality IAQ Override Smoke ControlOFF Mode DisabledNot AssignedOverview Plan the SystemDetermine Other Bus Devices Required Step No DescriptionLay Out Communications and Power Wiring Lonworks Bus LayoutExcel VAV Cvahu Power Budget Calculation Example Power WiringDeviceVA Information Obtained from VA Ratings For Transformer Sizing Device Description ML6161A/B Damper Actuator, 35 lb-in R8242A ContactorML7984B PWM Valve Actuator Line LossPower wiring details for one Excel 10 per Transformer Nema class 2 transformer voltage output limitsPrepare Wiring Diagrams General ConsiderationsW7750 Controllers Factory Default Digital Outputs Terminal Terminal Number DescriptionConstant Volume AHU Controller ML6161 Floating Actuator COM CCW Load Controller Power Heat Wall Economizer Damper PWM Actuator Power Signal W7750C Constant Lonworks Bus Termination Module Pneumatic transducer to W7750B,C Shown, see triangle noteBrown Orange Lonworks Bus termination wiring options Order EquipmentHoneywell Logo T7770D1018 T7770 and T7560 Wall ModulesSensor with Bypass/LED and Lonworks Jack Accessories Accessories SensorsEchelon Based Components and Parts Configure Controllers TroubleshootingTroubleshooting Excel 10 Controllers and Wall Modules CablingExcel 10 Alarms AlarmsResistance Value ohms Broadcasting the Service Message W7750 Controller Status LEDAppendix A. Using E-Vision to Commission a W7750 Controller Setting the Pid ParametersT7770C,D Wall Module Bypass Pushbutton and Override LED Sensor CalibrationAppendix B. Sequences of Operation Common Operations Room Temperature Sensor RmTemp HeatingEconomizer IAQ OptionBypass Mode StatusOvrd and StatusLed Remote Setpoint RmtStptPotSetpoint Limits LoSetptLim and HiSetptLim BypassTimeContinuous Unoccupied Mode Occupancy Mode and Manual Override ArbitrationNot Assigned Bypass OccupiedRecovery Ramping for Heat Pump Systems Time Clock OccTimeClockSchedule Master SchedMaster Setpoint RampingWindow Sensor StatusWndw Smoke ControlFAN Operation Demand Limit Control DLCSee for a diagram of a typical W7750 Unit Temperature Control OperationsDirty Filter Monitor Staged Cooling Control ONE StageTWO Stages Three StagesCascade Control of Modulating COOLING/HEATING Series 60 Modulating ControlPulse Width Modulating PWM Control Outdoor AIR Lockout of HEATING/COOLINGEconomizer ENABLE/DISABLE Control Indoor AIR Quality IAQ OverrideFreeze Stat Discharge AIR LOW Limit ControlInput Output Points Address Control Parameters AddressEnergy Management Points Address Status Points AddressMappable User Addresses and Table Number Relative Temperature Air FlowCO2 Concentration EnthalpyApplication reset therefore, these points can Placed in manual mode through a menuValid states and the corresponding Enumerated values are shownDefault Input/Output PointsNvName Field Name CommentsNciIoSelect DigitalIn1 Occsensor Shcedmasterin255 NciIoSelect DigitalIn2 Occsensor UnuseddiCOOLSTAGE1 COOLSTAGE2COOLSTAGE3 COOLSTAGE4Sixtyfifty SiinvalidFalse PPM SiinvalidTrue EconEnSw NvoIO EconEnableIn Position when poor indoor air quality is detectedStatusDI3 NvoIO UbDigitalIn OccSensr NvoIODefault Comments NvNameControl Parameters OdEnthalpyEnable MaxClRamp NciAux1SetPt UbMaxClRampS0 Degrees F/HrMinClRamp NciAux1SetPt UbMinClRampS0 Degrees F/Hr MaxClRamp, OdTempMaxClRamp,PPM Discharge air temperature cascade control loop GainCoolProp NciAux2SetPt UbKpCoolS2 Degrees F Degrees CGain for the cooling control loop GainHeatProp NciAux2SetPt UbKpHeatS2 Degrees F Degrees CEnergy Management Points Refer to WSHPEnable.value NviFree1 ValueAuxiliary functions. nviFree1 controls the FREE1OUT Network variable input failsNviTimeClk Value DestTimeClk NviTimeClk StateRefer to nviTimeClk.value 255 SrcTimeClkCt NvoTimeClk ValueStatus Points Alarmbit1 Bit Offset = SensorFailAlrmBit Offset = FrostProtectAlrm Bit Offset = InvalidSetPtAlrmNoalarm NodedisabledSmokealarm UpdateallfieldsDisabledmode StartupwaitHeat CoolStatusEconEn NvoData1 EconEnable Air flow switch is configuredNciAux1SetPts.ubOdEnthalpyEnableS2 StatusManOcc NvoData1 NetManOccHeatStgsOn NvoData1 HeatStagesOn Auxiliary heating stages are turned onCoolStgsOn NvoData1 CoolStagesOn For both heating or coolingIs 1, the algorithm controls as per the settings found NciConfig.SmokeControlController mode is switched to Freezeprotect MonitorSw NvoData1 MonSwitchBypasstimerfield TempcontrolptfieldSpacetempfield DischargetempfieldUbinvalid StatusError NvoError Errorbit0 SpaceTempErrorNvoError Errorbit0 Bit Offset = Temperature SetPtError NvoError Errorbit0NvoError Errorbit1 Bit Offset = RtnEnthalpyError NvoError Errorbit1Are disabled as if the sensor was not configured Bit Offset = SpaceCO2Error NvoError Errorbit1Bit Offset = NvWindowError NvoError Errorbit2 Bit Offset = NvDlcShedError NvoError Errorbit2Bit Offset = NvTodEventError NvoError Errorbit3 Bit Offset = NvByPassError NvoError Errorbit3Cfglocal CfgexternalCfgnul Calibration PointsConfiguration Parameters False True DisMinHtTime NciConfig DisableHeatMinTime DisMinClTime NciConfig DisableCoolMinTimeCascCntrl NciConfig CascadeControl UseRaTempCtl NciConfigLast NET Offset AbsolutemiddleNone Normal BypassonlyLonmark /Open System Points Hvacauto HvacheatHvacmrngwrmup Hvacprecool Hvaccool Hvacnightpurge Hvacnul Hvacoff74-2958 100 DestRmTemp NviSpaceTemp Degrees FSNVTtempp 14 to SrcRmTemp NvoSpaceTemp Degrees FHvacmrngwrmup Hvacauto HvacnulHvactest Alarmnotifydisabled NvoStatus Electricalfault 103 NvoStatus Inalarm255 Not configured 74-2958 NvoStatus UnabletomeasureSwon On other nodes. If the economizer function is configured by Corresponding economizer function is not enabled becauseSrcEconEnable NvoEcon State SrcEconEnCt NvoEcon ValueDirect Access And Special Points OFF Data Share Points Approximate Memory Size Estimating Procedure =using One-to-Many and not using points= including mapped points and others for Mapped points = number of mapped points per ExcelSensor Resistance Versus Temperature Resistance Ohms Resistance SensorsSensor Type Sensor UseOffset Setpoint Temperature Direct Setpoint TemperatureT7770B,C 10K ohm setpoint potentiometer Relative Above and Below Setpoint Resistance OhmsSensor Voltage Versus Humidity Humidity Percentage Voltage/Current SensorsSensor Voltage Versus Humidity Relative Humidity Percentage Sensor Current Versus Enthalpy volts Enthalpy mA 113 74-295874-2958 114 T7242 or equivalentMAmAmAmA AmA mA mA Sensor Voltage Versus Input Voltage To A/D Voltage to A/D Sensor Voltage Vdc Versus Pressure Inw Pressure Inw kPa Sensor Voltage VdcInw 50.0.13
Top Page Image Contents