Product Overview
The Allen-Bradley 1756-PSCA2 is a ControlLogix chassis adapter module that channels power from one or two redundant power supplies into the single power connector on the chassis backplane. This module is essential for building a redundant power supply system for ControlLogix chassis, ensuring high availability in critical industrial applications.
Designed for use with Standard Series B chassis, the 1756-PSCA2 mounts to the left of the chassis and connects to the power supply using a 1756-CPR2 cable. It is an open-type passive device with a current capacity of 1.5 A at 1.2V DC, 4 A at 3.3V DC, 15 A at 5.1V DC, and 2.8 A at 24V DC.
Technical Specifications
| Specification |
Value |
| Manufacturer |
Rockwell Automation |
| Brand |
Allen-Bradley |
| Part Number |
1756-PSCA2 |
| Series |
ControlLogix |
| Module Type |
Chassis Adapter Module for Redundant Power Supply |
| Weight |
8.1 ounces (0.228 kilograms) |
| Dimensions |
5.51 x 4.41 x 5.71 inches |
| Mounting |
Chassis - Left |
| Operating Temperature |
32-140 Fahrenheit (0-60 Celsius) |
| Backplane Current (24 Volts) |
125 milliamps |
| Power Dissipation (Max) |
25.7 Watts at 30 Celsius, 21.3 Watts at 60 Celsius |
| Removable Terminal Blocks |
3 RTBs, 1756-TBSH or 1756-TBNH |
| Enclosure |
None |
| UPC |
10612598307699 |
Industry Applications
The 1756-PSCA2 is widely used in process industries, manufacturing plants, and utility facilities where uninterrupted control system operation is critical. In a typical redundant power configuration, two power supplies feed the 1756-PSCA2, which distributes power to the backplane. If one supply fails, the other takes over seamlessly, preventing downtime.
For example, in a continuous production line, a power supply failure could halt the entire process, causing significant losses. With the 1756-PSCA2, the system remains operational, allowing maintenance to replace the faulty supply without stopping production.
Installation & Setup
Mount the 1756-PSCA2 horizontally on the left side of the chassis. Connect it to the power supply using a 1756-CPR2 cable, which requires a minimum bend radius of 5 inches (12.7 cm) for proper routing. Ensure the device is grounded according to the application's grounding requirements. Some installations may require an additional protective earth-ground terminal stud to link the chassis to the ground bus. Keep wire lengths as short as possible to minimize resistance.
Maintenance & Reliability
Because the 1756-PSCA2 is a passive device with no moving parts, it requires minimal maintenance. However, periodic inspection of connections and cable integrity is recommended to ensure reliable operation. Operating within the specified temperature range (0-60 Celsius) and avoiding exposure to moisture or contaminants will extend service life. The module's power dissipation values (25.7 W at 30°C, 21.3 W at 60°C) indicate that it runs cool, contributing to long-term reliability.
Compatibility & Integration
The 1756-PSCA2 is compatible with Bulletin 1756-PA75R and 1756-PB75R power supplies. It works with ControlLogix Standard Series B chassis. Only one 1756-PSCA2 is required per redundant power system, simplifying integration. The module supports 1756-TBSH or 1756-TBNH removable terminal blocks.
Selection Guide
Before purchasing, verify that your chassis is a Standard Series B and that you have the correct power supplies (1756-PA75R or 1756-PB75R). Also, ensure you have the 1756-CPR2 cable and the appropriate terminal blocks (1756-TBSH or 1756-TBNH). PLC Source PRO stocks the Allen-Bradley 1756-PSCA2 and can provide fast shipping to keep your project on schedule.