Carrier 48/50PD05 User Manual

23Temperature Compensated Start LogicThe following conditions must be met for the algorithm to run:S Unit is in unoccupied state.S Next occupied time is valid.S Current time of day is valid.S Valid space temperature reading is available (sensor or CCNnetwork).The algorithm will calculate a Start Bias time in minutes using thefollowing equations:If (space temperature > occupied cooling set point)Start Bias Time = (space temperature -- occupied cooling setpoint)*TCS.CIf (space temperature < occupied heating set point)Start Bias Time = (occupied heating set point -- spacetemperature)*TCS.HWhen the Start Bias Time is greater than zero the algorithm willsubtract it from the next occupied time to calculate the new starttime. When the new start time is reached, the TemperatureCompensated Start mode is set, the fan is started and the unitcontrolled as in an occupied state. Once set, TemperatureCompensated mode will stay on until the unit goes into theOccupied mode. The Start Bias Time will be written into the CCNLinkage Equipment Table if the unit is controlled in DAV mode. Ifthe Unoccupied Economizer Free Cool mode is active whentemperature compensated start begins, the Unoccupied Free Coolmode will be stopped.IMPORTANT: The maximum minutes Start Bias can be is 180.Carrier Comfort Network (CCN)RConfigurationIt is possible to configure the ComfortLink™ control to participateas an element of the Carrier Comfort Network (CCN) systemdirectly from the local display. This section will deal withexplaining the various programmable options which are foundunder the CCN sub-menu in the Configuration mode.The major configurations for CCN programming are located in thelocal displays at Configuration→CCN. See Appendix A.CCN Address (CCN.A)This configuration is the CCN address the rooftop is assigned.CCN Address (CCN.B)This configuration is the CCN bus the rooftop is assigned.CCN Baud Rate (BAUD)This configuration is the CCN baud rate.CCN Time/Date Broadcast (BROD→B.TIM)If this configuration is set to ON, the control will periodically sendthe time and date out onto the CCN bus once a minute. If thisdevice is on a CCN network then it will be important to make surethat only one device on the bus has this configuration set to ON. Ifmore than one time broadcaster is present, problems with the timewill occur.IMPORTANT: Only the time and date broadcaster can performdaylight savings time adjustments. Even if the rooftop is standalone, the user may want to set this to ON to accomplish thedaylight/savings function.CCN OAT Broadcast (BROD→B.OAT)If this configuration is set to ON, the control will periodicallybroadcast its outside-air temperature at a rate of once every 30minutes.Global Schedule Broadcast (BROD→B.GS)If this configuration is set to ON and the schedule number(SCH.N) is between 65 and 99, then the control will broadcast theinternal time schedule once every 2 minutes.CCN Broadcast Acknowledger (BROD→B.ACK)If this configuration is set to ON, then when any broadcasting isdone on the bus, this device will respond to and acknowledge.Only one device per bus can be configured for this option.Schedule Number (SCH.O→SCH.N)This configuration determines what schedule the control mayfollow.SCH.N = 0 The control is always occupied.SCH.N = 1 The control follows its internal timeschedules. The user may enter anynumber between 1 and 64 but it willbe overwritten to “1” by the controlas it only has one internal schedule.SCH.N = 65--99 The control is either set up toreceive to a broadcasted timeschedule set to this number or thecontrol is set up to broadcast itsinternal time schedule (B.GS) to thenetwork and this is the globalschedule number it is broadcasting.If this is the case, then the controlstill follows its internal timeschedules.Accept Global Holidays? (SCH.O→HOL.G)If a device is broadcasting the time on the bus, it is possible toaccept the time yet not accept the global holiday from the broadcastmessage.Override Time Limit (SCH.O→OV.TL)This configuration allows the user to decide how long an overrideoccurs when it is initiated. The override may be configured from 1to 4 hours. If the time is set to 0, the override function willbecome disabled.Timed Override Hours (SCH.O→OV.EX)This displays the current number of hours left in an override. It ispossible to cancel an override in progress by writing “0” to thisvariable, thereby removing the override time left.SPT Override Enabled? (SCH.O→OV.SP)If a space sensor is present, then it is possible to override anunoccupied period by pushing the override button on the T55 orT56 sensor. This option allows the user to disable this function bysetting this configuration to NO.Demand LimitDemand Limit Control may override the cooling algorithm to limitor reduce cooling capacity during run time. The term DemandLimit Control refers to the restriction of machine capacity tocontrol the amount of power that a machine will use. This can savethe owner money by limiting peaks in the power supply. Demandlimit control is intended to interface with an external networksystem. This is through a CCN Loadshed POC Device or writingto network points.To limit stages through network writes, the points Run Status→COOL→MAX.C and Run Status→HEAT→MAX.H are forcedon the network through CCN points MAX_CAPC andMAXHSTGS respectively. Force these to the desired maximumcooling/dehumidification capacity and the maximum heatingstages, respectively. When there is no force on these points, theyautomatically reset to allow full cooling/dehumidification capacityand all heating stages to be used. These points are reset atpower--on/reset (POR).When using the Loadshed POC to do Demand Limiting, the coolcapacity and heat stage limits under both Redline and Loadshedconditions can be set individually with configuration decisions. Ifthe active stages are greater then the loadshed or redlineconfigurations when a loadshed or redline command is given, theunit will reduce capacity or remove stages. The configurationpoints can be found in Configuration→CCN→LDS.48/50PD