The 1756-PSCA2 ControlLogix Redundant Power Supply Chassis Adapter from Rockwell Automation is an essential interface module used in ControlLogix redundant power architectures.
Instead of directly feeding the chassis backplane, the PSCA2 acts as a power aggregation and distribution adapter, combining output from two redundant power supplies (AC or DC) into a single, stable backplane power connection.
It is a core component in high-availability ControlLogix systems, ensuring uninterrupted PLC operation in critical industrial environments such as oil & gas, utilities, power generation, chemical processing, and continuous manufacturing.
Key Function
The 1756-PSCA2 is not a power supply itself. Its main roles are:
- Combines power from two redundant 1756 power supplies (e.g., 1756-PA75R / 1756-PB75R)
- Provides a single controlled power interface to the ControlLogix chassis
- Enables automatic redundancy switching and load sharing
- Supports system continuity during power module replacement or failure
Technical Specifications (Including Size & Weight)
| Parameter | Specification |
|---|---|
| Model | 1756-PSCA2 |
| Series | ControlLogix Redundant Power System Components |
| Module Type | Redundant Power Supply Chassis Adapter |
| Function | Combines dual power supplies into single backplane feed |
| Compatible Power Supplies | 1756-PA75R, 1756-PB75R, 1756-PAXTR, 1756-PBXTR |
| Backplane Current (5.1V DC) | Up to 15 A |
| Backplane Current (3.3V DC) | 4 A |
| Backplane Current (24V DC) | 2.8 A |
| Backplane Current (1.2V DC) | 1.5 A |
| Power Dissipation | ~21–26 W |
| Input Connection | 1756-CPR2 redundant power cable |
| Mounting Position | Left side of ControlLogix chassis |
| Installation Requirement | 3 RTB connectors (1756-TBSH / TBNH) |
| Operating Temperature | 0°C to 60°C |
| Storage Temperature | -40°C to 85°C |
| Relative Humidity | 5%–95% non-condensing |
| Vibration | 2 g @ 10–500 Hz |
| Shock | 30 g operating |
| Weight | ~0.23 kg |
Physical Dimensions
- Size (H × W × D): 140 × 145 × 145 mm (approx.)
The module occupies the left-side chassis mounting position and serves as the central interface point for redundant power architecture integration.
System Role in Redundant Architecture
In a redundant ControlLogix power system:
- Two power supplies are installed (e.g., 1756-PB75R + 1756-PB75R backup)
- Both connect to the PSCA2 using redundant power cables (1756-CPR2)
- PSCA2 merges and manages power delivery
- Chassis receives single stable backplane power feed
- If one supply fails, the other maintains full operation instantly
This architecture is designed to achieve zero downtime operation in critical control systems.
Recommended Related Models
The 1756-PSCA2 is typically used with:
- 1756-PA75R redundant AC power supply
- 1756-PB75R redundant DC power supply
- 1756-PAXTR / PBXTR XT redundant supplies
- 1756-CPR2 redundant power cable
- 1756-L71 / L73 ControlLogix CPUs
- 1756-EN2T communication modules
- 1756-A7 / A10 chassis systems
