1794-TB3 FLEX I/O 3-Wire Terminal Base Unit | Allen-Bradley

The Original New Allen-Bradley 1794-TB3 FLEX I/O Terminal Base Unit is the physical mounting and wiring foundation for FLEX I/O distributed I/O systems. This 3-wire cage clamp terminal base provides termination points for field devices and power supply connections while hosting FLEX I/O modules. It is primarily intended for use with input modules using 3-wire proximity switches and can also be used with output modules. The base unit snaps onto a DIN rail and plugs together with adjacent bases to form the backplane, enabling modular, space-efficient I/O system expansion.

Core Engineering Highlights:
52 terminals (16 I/O + 18 common + 18 +V) | Cage clamp termination | 3-wire configuration | 10A current rating | 125V AC/DC continuous | Up to 132V AC max | 640 mA @ 5V DC FlexBus current | 0.21–1.3 mm² (24–16 AWG) stranded copper wire | –20°C to +70°C operating | 94 x 94 x 69 mm | DIN rail mount

Key Features:

• Original New Allen-Bradley 1794-TB3 terminal base unit

• 3-wire cage clamp termination for secure, tool-free wire connections

• 52 terminals organized into three rows: 16 I/O terminals (row A), 18 common terminals (row B), and 18 +V terminals (row C)

• Primarily intended for use with input modules using 3-wire proximity switches

• Also compatible with output modules for flexible system configuration

• Plugs together with adjacent terminal bases to form the FLEX I/O backplane

• Snaps onto standard 35mm DIN rail for easy installation

• Supports daisy-chaining for simplified field wiring

• Open-style enclosure with IP20 protection

• Compact form factor reduces panel wiring space

Applications:

• Distributed I/O systems in industrial automation

• Field wiring termination for FLEX I/O modules

• 3-wire sensor and actuator connections

• Control panel I/O expansion

• Factory automation and machine control systems

• Industrial automation panel installations

Technical Specifications:

• Catalog Number: 1794-TB3

• Product Family: FLEX I/O (Bulletin 1794)

• Product Type: Terminal Base Unit, 3-Wire Cage Clamp

• Termination Type: Cage Clamp

• Wiring Style: 3-wire

• Terminals: 16 I/O; 18 common; 18 +V (52 terminals total)

• Current Rating: 10A

• Voltage Rating: 125V AC/DC continuous; up to 132V AC max

• FlexBus Current: 640 mA @ 5V DC

• I/O Terminal Current: 2A max

• Wire Size: 0.21–1.3 mm² (24–16 AWG) stranded copper wire rated at 105°C (221°F) or greater

• Insulation Thickness: 1.2 mm (3/64 in.) max

• Isolation Voltage: 125V continuous max, field wiring terminals to FlexBus

• Dimensions (HxWxD): 94 x 94 x 69 mm (3.7 x 3.7 x 2.7 in.)

• Weight: Approx. 0.44 lbs (0.20 kg)

• Mounting: DIN rail (35mm)

• Operating Temperature: –20°C to +70°C

• Backplane Current Draw: 640 mA @ 5V DC

• Certifications: Australian RCM, China CCC, Registro Italiano Navale, American Bureau of Shipping

• Lifecycle Status: Active Mature

• Country of Origin: Singapore

• UPC: 662468112352

System Compatibility:

• Allen-Bradley FLEX I/O digital input modules (e.g., 1794-IB16, 1794-IA16, 1794-IC16)

• FLEX I/O digital output modules (e.g., 1794-OB16, 1794-OA8, 1794-OC16)

• FLEX I/O analog modules (e.g., 1794-IE8, 1794-OE4)

• FLEX I/O specialty modules (e.g., 1794-IR8, 1794-IT8)

• 1794-TB3S – spring clamp version of the 1794-TB3

• 1794-TB3K – conformal coated version for harsh environments

• FLEX I/O communication adapters (1794-AENT, 1794-ACN15, 1794-ADN)

Typical System Architecture:
FLEX I/O Communication Adapter (e.g., 1794-AENT)
↓
1794-TB3 Terminal Base Unit (with I/O module installed)
↓
Additional 1794-TB3 Terminal Base Units (daisy-chained)
↓
FLEX I/O Modules (digital, analog, specialty)
↓
Field Devices (sensors, actuators, 3-wire proximity switches)

Related Products:

• 1794-TB3S – Spring clamp version of 1794-TB3 for faster wire installation

• 1794-TB3K – Conformal coated version for harsh environments

• 1794-TB2 – 2-wire version of the 1794-TB3

• 1794-TBN – Terminal base with different wiring configuration

• 1794-IB16 – 16-point 24V DC digital input module

• 1794-OB16 – 16-point 24V DC digital output module

• 1794-IE8 – 8-channel analog input module

• 1794-AENT – FLEX I/O EtherNet/IP adapter

• 1794-ACN15 – FLEX I/O ControlNet adapter

• 1794-ADN – FLEX I/O DeviceNet adapter

PLC ERA is an independent industrial automation distributor supplying 100% genuine Original New products through established global supply channels. Allen-Bradley, FLEX I/O, ControlLogix, and CompactLogix are trademarks of Rockwell Automation.