Features:
- Integral Terminal Base for FLEX Ex Intrinsically Safe Distributed I/O System
- Provides Secure Screw-cage Connections with Channel-to-Channel Isolation Capability
- Supports Safe Operation in Hazardous Environments Through Dedicated Intrinsically Safe Circuit Terminals
The Allen-Bradley 1797-TB3 FLEX Ex Screw-cage Terminal Base serves as the fundamental wiring interface for FLEX Ex modules, establishing reliable field connections within intrinsically safe distributed I/O architectures. It accommodates a total of 52 terminals arranged in one row of 16 terminals and two rows of 18 terminals each, with specific terminal assignments designated for the female I/O connector pins 30…32, 62…64, and 94…96 at terminals +34, -35, +50, -51, and 96, and terminals 36 and 49 reserved for connections with ratings of Ui less than 30V dc and Ii less than 100 mA. All remaining terminals are exclusively allocated for intrinsically safe circuits with ratings of Ui less than 10V dc and Ii less than 2.5 A, ensuring strict segregation between safety-rated and standard wiring paths. The unit requires a screw torque between 0.8 and 1 N-m for secure terminal connections and delivers channel-to-channel isolation determined by the inserted module, directly affecting the integrity and safe operation of the overall FLEX Ex system.
The 1797-TB3 occupies a compact footprint with installed dimensions of 3.7 inches in width, 3.7 inches in length, and 2.7 inches in height, weighing approximately 200 grams, and mounts conveniently via DIN rail configurations. It is always utilized in conjunction with FLEX Ex I/O modules to provide the essential terminal base functions common to each module installation, and one 1797-TB3 terminal base is required per FLEX Ex module depending on the specific I/O configuration.
For intrinsically safe Flexbus communication, the 1797-TB3 terminal base incorporates a dedicated Flexbus connection rated intrinsically safe with Ui less than 10V dc, Ii less than 400 mA, Ci less than 1 nF, and negligible Li, enabling safe daisy-chaining between adjacent FLEX Ex modules. In addition to standard single-module wiring, the terminal base also supports proper grounding and shielding practices. The 1797-TB3 FLEX Ex terminal base executes reliable signal distribution using the screw-cage terminal design specified in the hardware specifications. Using this method, the terminal base continually maintains secure wire retention and electrical continuity. If the system requires maintenance or module replacement, the wiring remains undisturbed on the 1797-TB3 while the electronic module is removed or inserted.
The 1797-TB3 Allen-Bradley FLEX Ex Screw-cage Terminal Base may still be available for purchase and support from Apter Power beyond End-Of-Life (EOL) by the manufacturer (OEM).
Allen-Bradley 1797-TB3 FLEX Ex Screw-cage Terminal Base Manuals,Datasheets,Link
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
Allen-Bradley 1797-TB3 FLEX Ex Screw-cage Terminal Base Specs
General
- Manufacturer Allen-Bradley
- Model 1797-TB3
- Condition New Original ready stock
- Product Family 1797-TB3S,1797-OE8,1797-IRT8
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
- Hazardous Environment Deployment: Primarily used in Zone 1, Zone 2, and Zone 22 (Europe) or Class I, Division 1 & 2 (North America) locations where explosive atmospheres from gases, vapors, or dust are likely to occur.
- Decentralised I/O Control: Ideal for applications requiring I/O connections near field devices in hazardous zones to reduce long wiring runs to safe areas.
- Industrial Automation: Commonly applied in oil and gas, chemical processing, and pharmaceutical industries where intrinsically safe apparatus is required by CENELEC, UL, and FM standards.
- Module Compatibility: Specifically designed for use with FLEX Ex I/O modules, such as analog, thermocouple, and frequency input modules (e.g., 1797-IE8, 1797-IJ2).
- System Integration: Compatible with the 1794 FLEX I/O system via bus isolator modules (1797-BIC/1797-CEC), allowing a mix of intrinsically safe and non-IS modules on the same backplane.
- Backplane Formation: Units plug together to form the Flexbus backplane, providing connection points for power and communication between modules.
- Wiring Density: Features 36 to 52 screw-clamp terminals (depending on configuration), supporting wire sizes from 22–12 AWG (0.34–2.5 ㎜² ) for compact, high-density connections.
- Rugged Environmental Tolerance: Operates efficiently from -20 °C to 70 °C and resists up to 15 G operational shock and 2 G vibration, ensuring reliability in harsh conditions.
- Intrinsic Safety Efficiency: Reduces costs by eliminating the need for bulky explosion-proof enclosures for every module, as the system itself is certified for Zone 1 installation.
- Quick Installation: Designed for DIN rail mounting with a locking latch mechanism for secure module placement and easy removal.