Honeywell W7752D specifications Setpoints, Setpoint Knob, Setpoint Limits, Setpoint from Network

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EXCEL 10 FCU CONTROLLER LNS PLUG-INS USER GUIDE

Fig. 3. Control sequence diagram

Setpoints

Setpoint Knob

The Excel 10 FCU Controllers may be hardwired to an Excel 10 wall module equipped with a setpoint knob. When the Excel 10 FCU Controller has been configured (using the LNS plug-in tool) to read input from the wall module's setpoint knob, the value from the setpoint knob is used to calculate the "occupied" setpoint for the heating and the cooling modes. There are two configurations which determine how the setpoint used by the control algorithm is calculated: "relative" (or "offset") and "absolute middle". When configured for "relative", the Excel 10 wall module setpoint knob represents a number from -9...+9 DDF(-5...+5 K) which is added to the configured "occupied" and "standby" setpoints for the heating and the cooling modes. When configured to "absolute middle", the setpoint knob becomes the mid-point of the Zero Energy Band (ZEB) extending between the "occupied" or "standby" setpoints for the heating and the cooling modes. The range of the ZEB is found by taking the difference between the "occupied" or "standby" setpoints configured for the heating and the cooling modes; in the case of "absolute middle", the current "occupied" and "standby" setpoints are therefore found as follows:

When the Excel 10 FCU Controller is in the "occupied" mode: nvoActiveSetPt (in cooling mode) =

nvoSensor.remote_set_point + (Cooling Occupied Setpoint - Heating Occupied Setpoint) / 2

nvoActiveSetPt (in heating mode) = nvoSensor.remote_set_point - (Cooling Occupied Setpoint - Heating Occupied Setpoint) / 2

for Standby:

nvoActiveSetPt (in cooling mode) = nvoSensor.remote_set_point + (Cooling Standby Setpoint - Heating Standby Setpoint) / 2

nvoActiveSetPt (in heating mode) = nvoSensor.remote_set_point - (Cooling Standby Setpoint - Heating Standby Setpoint) / 2

When the Excel 10 FCU Controller is in the "unoccupied" mode, the remote setpoint knob is ignored, and the con- figured setpoints for this mode are used instead.

Setpoint Limits

Setpoints are limited to the range of 50...95°F (10...35°C). The value of the setpoint knob is limited to the range provided by the configuration parameters Maximum Limit Setpoint pot and Minimum Limit Setpoint pot. In the case of absolute "occupied" and "standby" setpoints, the setpoint knob still represents the mid-point of the ZEB, even when set to either of these limits. The actual setpoints are given by the equations shown above. When the setpoint knob is configured to be "relative", the lowest actual "occupied" setpoint allowed is equal to SptHeatOcc - SptKnobLowLim, and the highest allowed is equal to SptCoolOcc + SptKnobHiLim. The lowest and highest "standby" setpoints are found in an analogous fashion.

Setpoint from Network

When the Excel 10 FCU Controller is not configured to be hardwired to a wall module, nviSetPoint must be bound to another node that provides a setpoint. When bound and when a valid update is received, nviSetPoint is used with the appropriate ZEB:

•ZEBoccupied = Cooling Occupied Septoint - Heating Occupied Setpoint

•ZEBstandby = Cooling Standby Setpoint - Heating Standby Setpoint

The "unoccupied" setpoint does not depend on nviSetPoint at all.

Setpoint Offset

Third-party nodes may be bound to nviSetPtOffset to shift the setpoint in the range of -18 to 18 DDF (-10 K to 10 K).

EN2B-0285GE51 R0909

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Contents Excel Appendix a Using An LNS tool to Commission a Fan Coil Unit Appendix B Configuring for Master/Slave OperationAppendix C LON Interface Revision History Description of Devices Typical system overviewApplicable Literature Products CoveredOrganization of Manual Product NamesControl Application Control ProvidedSetpoint Limits SetpointsSetpoint Knob Setpoint from NetworkZEB Energy-Saving Features BypassOccupancy Status Safety Features Operating ModesExcel 10 W7754 FCU Controllers ConstructionExcel 10 W7752 FCU Controllers Electrical Shock Hazard180 Controller Performance Specifications Configurations GeneralFan Type Type of Heating and Cooling Equipment Reheat Output Digital InputCommon Temperature Control Master/Slave Controllers Excel 10 Wall Module OptionsAbbreviations and Definitions Determine Other Bus Devices Required OverviewPlan the System Step No DescriptionLay Out Communications and Power Wiring Lonworks LayoutPrepare Wiring Diagrams Power WiringGeneral Considerations Vendor wire type WiringPower PlenumLOW 230 ONW Orks Termination XAL-TermExcel 10 Sensors Order EquipmentExcel 10 Wall Modules Echelon-Based Components and PartsConfigure Controllers Using Plug-InsOutput Input Equipment Control FanSwitching Levels Zone OptionsMiscellaneous Alarms TroubleshootingTroubleshooting Excel 10 FCU Controllers and Wall Modules CommissioningFCU Alarms ReturntonormalBroadcasting the Service Message Manual ModeTemperature Sensor Calibration ProcedureZone Control Options Output Configuration OptionsInput Configuration Options Network Variable BindingAppendix C LON Interface Page NV name Continuous Automode To 100% For the reheat output EN2B-0285GE51 R0909 Ntcnonlinearized NoswitchByte Ntcnonlinearize Byte FivepositionDioccupiedsensor Byte DinotusedDiwindowclosed DiairflowTwostage Byte FloatingOnestage ThreestageByte Reheat FreeuseRelnotused Fourpipe TwopipeUword Bypassunoccupie OffsetAbsolutemiddle NobuttonTable C3. Input Variables for Excel 10 FCU Controllers Suppressalarms Modeenable UnsuppressalarmsModedisable OcnulRqnormal Rqupdatestatus Rqupdatealarm Rqreportmask OFF NULInvalid ON1OFF2 Byte NormalhcmodeOFF1OFF2 OFF1ON2Byte Normalfanmode Ledoff LedonNowindow ClosedOpen Table C4. Output Variables for Excel 10 FCU Controllers Rtncomfailsetptoffs RtncomfailtempresetAlarmnotifydisabled RtncomfailschedoccAlmcomfailmanheat Almcomfailmancool Almhwswmismatch OFF NotassignedOcbypass Ocstandby Fieldhwoverride OFF Nofanspeedsw UbyteFieldeffectocc FieldschedoccOcunoccupied Ocbypass Ocstandby CtlfanswitchoffCtldisabled Ocunoccupied Ocbypass Ocstandby OcnulFanruns Not Actice ActiveFanoffafteroncmd ExternalnotacticeStoff StonInvalid Uword Pressed OFF NoreheatNotpressed Contactopen Contactclosed UwordStlow Stmed Sthigh Invalid Byte InitialNoalarm EnabledDisabled InalarmAlarm Suppressalarms Alarmnotifydisabled Open NowindowBugver Nodetype Table C5. Unused Variables for Excel 10 FCU Controllers WordAutomation and Control Solutions

W7752D specifications

The Honeywell W7752D is a versatile and advanced electronic gas combination control designed primarily for use in commercial heating systems. This product stands out for its ability to manage both gas ignition and safety functions, which are critical for maintaining the efficiency and safety of heating appliances. Its robust construction and advanced features make it a popular choice for HVAC professionals and service technicians.

One of the main features of the W7752D is its integration of multiple functions in a single device. It serves as both an automatic gas ignition control and a safety shut-off valve, which simplifies installation and reduces the need for additional components. This integrated design not only enhances reliability but also streamlines maintenance procedures.

Another notable technology utilized in the W7752D is its microprocessor-based control logic. This advanced technology allows for precise management of the ignition sequence, improving the overall efficiency of the heating system. The microprocessor enables the control to adapt to varying operating conditions, ensuring optimal performance even under changing demands.

The W7752D is equipped with features that enhance user-interface and diagnostics capabilities. It includes LED indicators that provide clear information about the operational status and any potential issues. This diagnostics capability facilitates easier troubleshooting, saving time and reducing the likelihood of extended downtimes.

Safety is a primary concern in gas appliances, and the W7752D addresses this with built-in safety mechanisms, including flame detection technologies. These features ensure that the appliance operates safely, automatically shutting down in case of any irregularities during operation. This emphasis on safety not only protects property but also provides peace of mind for users.

In terms of compatibility, the Honeywell W7752D is designed to work with a wide range of gas heating appliances. Its flexibility allows it to be used in various applications, making it suitable for different types of commercial environments. Additionally, the control complies with relevant safety and performance standards, ensuring reliable operation.

In summary, the Honeywell W7752D combines advanced technology with essential safety features, making it a top choice for commercial heating applications. Its integrated design, microprocessor-based control, user-friendly diagnostics, and robust safety mechanisms make it an essential component for efficient and safe gas heating systems. Whether it is for new installations or replacements, the W7752D provides HVAC professionals with the reliability and ease of use they demand.
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