Application Scenarios:
A food and beverage packaging OEM was designing a high-speed bottling line control panel with a 1769-L32E controller and 12 mixed I/O modules (digital, analog, and specialty). The panel was powered by a centralized 24V DC UPS system for brown-out protection. The challenge was to efficiently distribute this DC power to the entire CompactLogix rack without introducing multiple point-of-load converters. By integrating the 1769-PB2 as the rack’s power supply, the design leveraged the module’s ability to take the 24V DC input and generate the required 5V logic and 24V sensor power internally. This simplified the bill of materials, reduced wiring complexity, and ensured stable operation during brief power sags, which had previously caused controller resets with less tolerant power supplies.
Parameter:
| Main Parameters | Value/Description |
|---|---|
| Product Model | 1769-PB2 |
| Manufacturer | Rockwell Automation (Allen-Bradley) |
| Product Category | Compact I/O DC Power Supply |
| Input Voltage | 19.2 – 31.2 VDC (Nominal 24 VDC) |
| Output Current | 2.0 A @ 5 VDC (Logic), 0.8 A @ 24 VDC (I/O) |
| Power Capacity | Supports up to 16 I/O modules (8 on each side) |
| Inrush Current | 30 A maximum (protected) |
| Fuse | 3.15 A (User-replaceable, e.g., Littelfuse 02153.15MXP) |
| Status Indication | Single Green LED (Output Power OK) |
| Operating Temp. | 0 °C to 60 °C (32 °F to 140 °F) |
| Mounting | DIN Rail (35mm) or Panel Mount |
| Dimensions (HxWxD) | 118 x 70 x 87 mm (4.65 x 2.76 x 3.43 in) |
Technical Principles and Innovative Values:
The 1769-PB2 is engineered as a robust DC-DC power converter that prioritizes system integrity and ease of use in space-constrained panels.
- Innovation Point 1: Dual-Voltage Backplane Power Management. Unlike generic power supplies, the 1769-PB2 is specifically designed for the CompactBus architecture. It intelligently distributes two critical voltage rails: a high-current 5V DC for module logic and a separate 24V DC for internal I/O circuitry. This dual-rail design ensures stable voltage levels even during high-speed I/O scanning, preventing logic errors.
- Innovation Point 2: Bi-Directional Power Distribution. A key mechanical innovation is its ability to power modules on both its left and right sides. This “power bridge” functionality allows it to be placed anywhere within the CompactLogix rack (start, middle, or end), supporting up to 8 modules in each direction. This provides unparalleled layout flexibility for system integrators.
- Innovation Point 3: Field-Fault Tolerant Design. The module incorporates reverse polarity protection and a high inrush current withstand capability (30A). This protects the module from common field wiring errors and allows it to reliably power up a full rack of capacitive loads without blowing fuses during startup, a common pain point with lower-grade supplies.
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