Description:The Allen-Bradley 2085-EP24VDC is a 24V DC expansion power supply module specifically designed for the Micro800 series (Micro850/Micro870) programmable controllers. Unlike a standard sensor power supply, this module is a “backplane power booster” that plugs directly into the 2085 expansion bus. It converts an external 24V DC input into regulated 5V and 24V DC for the PLC’s internal backplane, allowing you to add more I/O modules (digital, analog, relay) beyond the base controller’s native power budget. It is essential for preventing communication faults and instability in high-density I/O configurations.Application Scenarios:In a Taiyuan-based automated packaging machine, a Micro850 controller was initially limited to 6 I/O modules due to backplane power constraints. By inserting a 2085-EP24VDC module in the middle of the rack (powered by an external 24V SMPS), the system successfully expanded to 12 modules (relay outputs and analog inputs) without upgrading the main PLC, saving significant cost and panel space while maintaining signal integrity.
Parameter:
| Parameter | Value / Specification |
|---|---|
| Product Model | 2085-EP24VDC |
| Manufacturer | Rockwell Automation (Allen-Bradley) |
| Product Type | Expansion Backplane Power Supply |
| Compatible Series | Micro800 (Micro850, Micro870) |
| Input Voltage | 24V DC (20.4 – 26.4V DC range) |
| Input Protection | Reverse Polarity Protected |
| Backplane Output | 5V DC @ 900 mA, 24V DC @ 700 mA |
| Max Bus Power | ~16.8 W (limited by module) |
| I/O Module Capacity | Supports up to 4 modules downstream |
| Status Indicator | 1 Green LED (5V System Power) |
| Mounting | 35mm DIN Rail (2085 expansion bus) |
| Operating Temperature | -20°C to 65°C |
Technical Principles and Innovative Values:The 2085-EP24VDC solves a critical bottleneck in compact control systems by decoupling backplane power from the CPU.
- Innovation Point 1: Backplane Power Injection Architecture. Traditional small PLCs often lack the internal power reserves to drive large I/O stacks. The 2085-EP24VDC introduces a “mid-bus power injection” strategy. Instead of replacing the entire controller, you insert this module into the expansion bus. It draws from an external 24V source and regenerates clean 5V/24V power for the downstream I/O modules, effectively acting as a “signal repeater” for both data and power on the backplane.
- Innovation Point 2: Deterministic Power Budgeting. The module provides a clear “4-module” power domain. This allows system designers to precisely calculate power budgets using Rockwell’s Connected Components Workbench (CCW) software. When the software indicates the base controller’s power is exceeded, adding this module is the prescribed solution, eliminating guesswork and preventing field failures due to undervoltage.
- Innovation Point 3: Isolation and Protection. Despite its compact size, the module incorporates reverse polarity protection and is designed to be powered by a SELV (Safety Extra Low Voltage) source. This protects the sensitive Micro800 backplane from external wiring errors and voltage transients, a critical feature in harsh industrial environments with heavy motor loads.
