Product Overview
The Allen-Bradley 1756-TBSH is a removable terminal block (RTB) designed for the ControlLogix product line. It provides a secure and flexible connection between 1756 I/O modules and plant wiring. This 20-pin spring-clamp terminal block comes with a standard housing and supports removal and insertion under power (RIUP), minimizing downtime during maintenance.
Key Specifications
| Parameter |
Value |
| Manufacturer |
Rockwell Automation |
| Brand |
Allen-Bradley |
| Part Number |
1756-TBSH |
| Series |
ControlLogix |
| Module Type |
Terminal Block |
| Clamp Type |
Spring-Clamp |
| Pins |
20-Pin Connection |
| Weight |
0.3 lb (0.1 kg) |
| Backplane Current (5V) |
1,200 mA |
| Backplane Current (24V) |
2.5 mA |
| Power Dissipation (Max) |
6.19 W |
| Wire Size |
20 AWG |
| Dimensions |
5.51 x 4.41 x 5.71 in |
| Operating Temperature |
32–140 °F (0–60 °C) |
| Enclosure |
None |
Technical Specifications Breakdown
The 1756-TBSH uses a spring-clamp mechanism, which provides a vibration-resistant and tool-free wiring connection. Its 20-pin design accommodates up to 20 individual conductors, but only one conductor per terminal is allowed. The terminal block draws 1,200 mA from the 5V backplane and 2.5 mA from the 24V backplane, with a maximum power dissipation of 6.19 W. Operating temperature range is 32 to 140 °F (0 to 60 °C), making it suitable for most industrial environments.
Industry Applications
This terminal block is used in a variety of control applications, including:
- Discrete I/O wiring for AC/DC digital input and output modules
- Analog signal connections for RTDs, thermocouples, and analog outputs
- Specialty I/O modules requiring reliable field wiring
Its spring-clamp design speeds up installation and reduces wiring errors, which is critical in high-uptime production lines.
Installation and Setup
To install the 1756-TBSH, align the terminal block with the front connector of the compatible 1756 I/O module and push it in until it latches. Use only one conductor per terminal. For solid or stranded copper wires rated at 90 °C (194 °F) or greater, the terminal accepts 0.33–2.1 mm² (22–14 AWG) wire with a maximum insulation diameter of 1.2 mm (3/64 in). Ensure the system is de-energized before installation unless performing a hot swap under RIUP procedures.
Maintenance and Reliability
The spring-clamp mechanism provides consistent contact pressure, reducing the need for periodic retightening. Inspect the terminal block periodically for signs of corrosion or overheating. Clean the contacts with a dry cloth if necessary. The standard housing offers protection against accidental contact, while the RIUP capability allows module replacement without shutting down the entire system, minimizing production losses.
Compatibility and Integration
The 1756-TBSH is compatible with selected 1756 series AC digital inputs, AC digital outputs, analog inputs, analog RTDs and thermocouples, analog outputs, and specialty I/O modules. It is part of the Bulletin 1756 removable terminal block family, ensuring a consistent interface across the ControlLogix platform.
Selection Guide
Before purchasing, verify the exact module model and the required terminal block type. The 1756-TBSH is a 20-pin spring-clamp version with a standard housing. Ensure your application matches the wire size and temperature ratings. PLC Source PRO offers genuine Allen-Bradley parts with fast shipping.