{"product_id":"honeywell-pub6438s-spyder-bacnet-unitary-programmable-controller","title":"Honeywell PUB6438S Spyder BACnet Unitary Programmable Controller","description":"\u003ch2\u003eHoneywell PUB6438S Spyder BACnet Programmable Controllers\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eHoneywell PUB6438S\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003ePUB6438S\u003c\/strong\u003e Programmable Unitary Controller, operates as a dedicated hardware component for unitary HVAC sequence execution within BACnet MS\/TP building automation networks. Communicating over an EIA-485 physical layer, the controller executes deterministic logic compiled via the NiagaraAX framework to govern rooftop units, heat pumps, and fan coil systems. The hardware integrates a dedicated Sylk bus interface to power and query two-wire wall modules while managing onboard analog inputs, analog outputs, and triac digital outputs across removable terminal blocks.\u003c\/p\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eParameter\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003ePUB6438S\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePart Number\u003c\/td\u003e\n\u003ctd\u003ePUB6438S\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eHoneywell\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCategory\u003c\/td\u003e\n\u003ctd\u003eHVAC Controllers\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eUSA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.42 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e162 x 125 x 48 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e-40 to 65 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e5.0 W\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eField Bus Protocol\u003c\/td\u003e\n\u003ctd\u003eBACnet MS\/TP over EIA-485\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInternal Bus\u003c\/td\u003e\n\u003ctd\u003eSylk bus for wall sensor modules\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutputs\u003c\/td\u003e\n\u003ctd\u003e3 Analog Outputs, 8 Triac Digital Outputs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNetwork Capacity\u003c\/td\u003e\n\u003ctd\u003eUp to 50 controllers per BACnet segment\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eDCS \u0026amp; Building Automation Signal Interconnection\u003c\/h3\u003e\n\u003cp\u003eThe controller processes field sensor telemetry and actuates analog and triac output circuits using standardized BACnet MS\/TP communication routines. Onboard signal conditioning networks isolate field-side 0-10 VDC or 4-20 mA analog outputs from internal microprocessors, maintaining low total harmonic distortion across actuator drive loops. Cold junction compensation (CJC) algorithms run continuously on temperature input paths, ensuring steady process variable conversion during ambient panel temperature swings from -40 to 65 deg C.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: How does the onboard Sylk bus interface communicate with field wall modules?\u003c\/p\u003e\n\u003cp\u003eA: The polarity-insensitive two-wire Sylk bus delivers operating power and digital communications simultaneously to compatible wall sensors, simplifying field wiring setups.\u003c\/p\u003e\n\u003cp\u003eQ: What precautions apply when powering the 8 triac digital outputs from an AC source?\u003c\/p\u003e\n\u003cp\u003eA: Triac outputs switch AC voltage only (24 VAC nominal) and require a common transformer reference to prevent improper phase alignment or continuous current leakage across connected relays.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eMount the controller securely onto a 35 mm DIN rail or directly to a panel enclosure wall using the provided mounting holes. Remove terminal blocks prior to landing wires to prevent accidental mechanical stress on the internal printed circuit board assembly. Route EIA-485 BACnet MS\/TP network cables in a daisy-chain configuration, setting 120 Ohm end-of-line termination resistors at the physical ends of the segment. Connect the communication cable shield directly to earth ground at one point only to avoid circulating ground potential differentials.\u003c\/p\u003e","brand":"HONEYWELL","offers":[{"title":"Default Title","offer_id":51284302954808,"sku":"PUB6438S","price":250.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0893\/1616\/3896\/files\/600.1_9d4b104d-bbc0-4c65-b145-b324f3498f5b.jpg?v=1791602667","url":"https:\/\/www.automodulexpert.com\/products\/honeywell-pub6438s-spyder-bacnet-unitary-programmable-controller","provider":"AutoModuleXpert Ltd.","version":"1.0","type":"link"}