Product Overview

The Allen-Bradley 1756-TBNH is a high-performance Removable Terminal Block (RTB) specifically engineered for the ControlLogix platform. This 20-position accessory acts as the primary physical interface between field-side wiring and ControlLogix I/O modules. By utilizing a removable design, the 1756-TBNH allows for complete system maintenance or module replacement without the need to disconnect individual field wires, significantly improving uptime and reducing the risk of wiring errors during service.

Equipped with NEMA-standard screw-clamp terminations, this terminal block provides a heavy-duty connection point suitable for industrial environments. It is designed to seat securely onto the front of the I/O module, providing a clean, organized, and electrically sound termination point for digital and analog signals.

Technical Characteristics and Connectivity

The 1756-TBNH is built to handle rigorous electrical requirements while maintaining a compact footprint within the PLC chassis.

• Terminal Count: 20-position screw-type termination points.

• Connection Type: Heavy-duty screw-clamp (NEMA).

• Tightening Torque: 1.36 Nm (12 lb-in) to ensure vibration-resistant contact.

• Wire Compatibility: Accepts solid or stranded copper wire sizes ranging from 22 AWG to 14 AWG ($0.33 mm^2$ to $2.1 mm^2$).

• Temperature Rating: Supports conductors rated up to 90°C for high-current or high-ambient applications.

• Wiring Capacity: Designed to allow the termination of up to two wires per signal point, providing flexible daisy-chaining options.

Environmental Reliability and Physical Specs

Designed for the standard industrial temperature range, the 1756-TBNH ensures signal integrity despite mechanical stress.

• Operating Temperature: 0°C to 60°C (32°F to 140°F).

• Shock and Vibration: Rated for 30g operational shock and 2g vibration at 10-500Hz.

• Module Dimensions: 14.5 x 13 x 3.5 cm.

• Shipping Weight: Approximately 0.9 kg (includes robust housing and metal terminal components).

• Housing Material: Reinforced thermoplastic with high dielectric strength.

Installation and Compatibility

The 1756-TBNH is compatible with a wide array of 1756 ControlLogix digital and analog I/O modules. It is specifically preferred in applications where NEMA-style screw terminals are required over spring-clamp alternatives. The mechanical interlocking mechanism ensures that the RTB remains firmly attached to the I/O module even in high-vibration machinery environments.