Carrier 50TC*17 Series Service And Maintenance Instructions

38RTU−OPEN CONTROL SYSTEMThe RTU Open controller is an integrated component ofthe Carrier rooftop unit. Its internal applicationprogramming provides optimum performance and energyefficiency. RTU Open enables the unit to run in 100%stand−alone control mode, Carrier’s I−Vu Open network,or a Third Party Building Automation System (BAS).On−board DIP switches allow you to select your protocol(and baud rate) of choice among the four most popularprotocols in use today: BACnet, Modbus, Johnson N2 andLonWorks.The RTU Open control is factory−mounted in the 50TCunit’s main control box, to the left of the LightCommercial Terminal Board (LCTB). See Fig. 44.Factory wiring is completed through harnesses connectedto the LCTB. Field connections for RTU Open sensorswill be made at the Phoenix connectors on the RTU Openboard. The factory−installed RTU Open control includesthe supply−air temperature (SAT) sensor. The outdoor airtemperature (OAT) sensor is included in theFIOP/accessory EconoMi$er2 package.Sensory/Accessory InstallationThere are a variety of sensors and accessories availablefor the RTU−OPEN. Some of these can be factory or fieldinstalled, while others are only field installable. TheRTU−OPEN controller may also require connection to abuilding network system or building zoning system. Allfield control wiring that connects to the RTU−OPEN mustbe routed through the raceway built into the corner post ofthe unit or secured to the unit control box with electricalconduit. The unit raceway provides the UL requiredclearance between high and low−voltage wiring. Pass thecontrol wires through the hole provided in the corner post,then feed the wires thorough the raceway to theRTU−OPEN. Connect the wires to the removable Phoenixconnectors and then reconnect the connectors to the board.See Fig. 44.IMPORTANT: Refer to the specific sensor or accessoryinstructions for its proper installation and for rooftop unitinstallation refer to base unit installation instructions andthe unit’s wiring diagrams.ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personalinjury or death, and/or equipment damage.Disconnect and lockout/tagout electrical power beforewiring the RTU−OPEN controller.! WARNINGAdditional RTU−OPEN Installation andTroubleshootingAdditional installation, wiring and troubleshootinginformation for the RTU−OPEN Controller can be foundin the following manuals: “Controls, Start−up, Operationand Troubleshooting Instructions,” and “RTU OpenInstallation and Start−up Guide.”