{"product_id":"1797-tb3-allen-bradley-flex-i-o-terminal-base-unit","title":"1797-TB3 Allen-Bradley FLEX I\/O Terminal Base Unit","description":"\u003cp\u003eConfigured for intrinsically safe I\/O termination and field wiring routing in hazardous area applications, the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen-Bradley 1797-TB3\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e(\u003cstrong\u003e1797-TB3\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eTerminal Base Unit) provides direct physical\/electrical execution. The hardware establishes a localized interface between field transmitters, actuators, and the active backplane architecture, managing voltage routing across multiple termination paths without compromising spark-containment design criteria.\u003c\/p\u003e\n\u003ch3\u003eTerminal Topology \u0026amp; Circuit Mapping\u003c\/h3\u003e\n\u003cp\u003eThe layout features a multi-tier physical design containing three termination strips that optimize routing density within small enclosure spaces. Terminal paths are physically segregated to separate active I\/O loop connections from shared common returns.\u003c\/p\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eTop Row: Dedicated to field I\/O active signal conductors.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMiddle Row: Assigned to common return terminations.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003ePhysical Layout: Two distinct terminal rows containing 1 row with 16 terminals and 1 row with 18 terminals, culminating in 52 total hardware connection points.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr class=\"firstRow\"\u003e\n\u003ctd\u003e\u003cstrong\u003eParameter\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eModel\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e1797-TB3\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eBrand\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eAllen-Bradley\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eOrigin\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eUSA\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eModule Type\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eTerminal Base Unit\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eTotal Terminals\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e52 points\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eTerminal Strips\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e3 strips\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eConnection Type\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eScrew clamp terminals\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eTerminal Screw Torque\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e0.56 to 0.79 Nm\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eIsolation Voltage\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e125 V Continuous\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eSupply Voltage Range Max\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e125 VAC \/ VDC, 50\/60 Hz, 10 A\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eVoltage Rating Options\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e24 VDC \/ VAC, 120 VDC \/ VAC\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eOperating Temp\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e-20 to +60 deg C\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003ePower Consumption\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003ePassive bus pass-through interface\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eTariff Code\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e8537101190\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eShipping Dimensions\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e10 cm x 9.5 cm x 6 cm\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eWeight\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e0.24 kg\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eDeterministic Network Architecture \u0026amp; Backplane Bus Velocity\u003c\/h3\u003e\n\u003cp\u003eThe terminal base assembly utilizes a passive electronic midplane that routes data links and module power directly through adjacent bases. This bus configuration supports distributed topologies across Profinet \/ EtherNet\/IP deterministic networks via adapter gateways. The internal structure does not restrict backplane bus communication velocity licenses, maintaining native data throughput while enforcing galvanic boundaries. Changes in I\/O density scaling are accommodated via the modular snap-fit interlocking design, ensuring that firmware flash compatibility is maintained across all attached active electronic modules.\u003c\/p\u003e\n\u003ch3\u003eOrdering Information\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003e1 x 1797-TB3 FlexEx Terminal Base Unit\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e2 x Interlocking bus connector covers\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003ch3\u003eMounting and Mechanical Alignment\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eSnap the terminal base directly onto standard DIN-rail assemblies, ensuring the side-locking bus connectors latch firmly with the preceding unit.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eTighten all terminal wire clamping screws to a torque specification between 0.56 and 0.79 Nm to maintain electrical contact stability.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eConductor Routing and Shielding Rules\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eKeep all intrinsically safe field wiring separated from non-intrinsically safe power infrastructure within the cabinet enclosure.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eGround the instrument cable shields at the designated enclosure bulkhead grounding busbar rather than at the terminal base frame.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eWhat is the hot-swap capability limitation regarding active electronic modules mounted to this unit?\u003c\/p\u003e\n\u003cp\u003eThe terminal base permits removal and insertion of compatible modules under field power, provided the area is verified non-hazardous or the module meets specific intrinsic safety standards.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eHow does the backplane power distribution operate across adjacent terminal assemblies?\u003c\/p\u003e\n\u003cp\u003ePower and communication links pass horizontally through the integrated side connectors, forming a continuous internal system bus across the assembled array without external jumpers.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eWhat type of conductor insulation and gauge is compatible with the integrated screw clamps?\u003c\/p\u003e\n\u003cp\u003eThe screw clamp mechanisms accommodate solid or stranded copper wire rated for industrial signaling, stripped to the manufacturer standard depth specified in the manual.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIs there any channel-to-channel electrical isolation built into this passive terminal base?\u003c\/p\u003e\n\u003cp\u003eNo, this unit provides point-to-point pass-through wiring, and any structural channel isolation is determined solely by the active I\/O module snapped onto the base.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eWhat occurs if the terminal screw torque falls outside the 0.56 to 0.79 Nm specification?\u003c\/p\u003e\n\u003cp\u003eUnder-torquing leads to increased contact resistance and potential open circuits, while over-torquing risks stripping the internal threads and damaging the contact plates.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCan this terminal base be deployed directly inside Class I Division 1 environments without an enclosure?\u003c\/p\u003e\n\u003cp\u003eThe hardware must be mounted inside an approved, dust-tight and moisture-protected industrial enclosure that complies with local zone regulations for hazardous areas.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eWhat is the continuous isolation voltage rating between the field wiring terminals and the backplane?\u003c\/p\u003e\n\u003cp\u003eThe physical layout and component separation provide a continuous isolation performance ceiling verified up to 125 V between the active processing logic and field loops.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eDoes this base unit contain active components that require configuration during software commissioning?\u003c\/p\u003e\n\u003cp\u003eNo, the terminal base is a purely passive mechanical and electrical routing interface that requires no software configuration, node addresses, or firmware flashes.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":46066460098733,"sku":"1797-TB3","price":88.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0733\/1613\/9181\/files\/1797-TB3_255.jpg?v=1784022631","url":"https:\/\/www.maxwellplc.com\/ga\/products\/1797-tb3-allen-bradley-flex-i-o-terminal-base-unit","provider":"Maxwell PLC Ltd","version":"1.0","type":"link"}