SR2B121FU Schneider Electric 12 I/O Smart Relay 100-240V AC

What Makes the SR2B121FU a Reliable Choice for Compact Control?

How do you implement dependable logic control in a panel where space is limited and wiring complexity must stay low? The SR2B121FU from Schneider Electric answers that challenge through the Zelio Logic compact smart relay platform. Specifically, this 12 I/O controller combines eight digital inputs, four relay outputs, and an integrated real-time clock in a DIN-rail housing. Consequently, engineers gain a precise, self-contained control solution for small automation tasks.

SR2B121FU Key Features and Verified Specifications

The SR2B121FU operates on a supply voltage of 100-240V AC (85-264V, 50/60 Hz). This wide input range tolerates real-world mains variation, so the relay remains stable during brownouts or overvoltage events. In addition, the eight digital inputs accept 100-240V AC signals directly. Therefore, you can wire pushbuttons, limit switches, and sensors without intermediate interface relays.

• I/O configuration: 12 total points — 8 digital inputs and 4 relay outputs.
• Relay output current: 8 A thermal current per output for direct load switching.
• Supply voltage: 100-240V AC, 85-264V range, 50/60 Hz.
• Clock: Integrated real-time clock for time-based control functions.
• Display: LCD with navigation buttons for local monitoring and adjustment.
• Program memory: 240 lines ladder or 500 blocks FBD.
• Mounting: 35 mm DIN rail.
• Dimensions (H×W×D): 90 × 71.2 × 59.5 mm; weight 0.25 kg.

Furthermore, the relay output contacts deliver a mechanical life of 10,000,000 cycles and an electrical life of 500,000 cycles at AC-12, 230V 1.5A per IEC 60947-5-1. These verified figures support long service intervals in switching-intensive applications.

Where the SR2B121FU Fits in Industrial Applications

Because the SR2B121FU combines logic, display, and I/O in one compact unit, it suits decentralized control tasks. For example, it can manage lighting schedules in a warehouse using its real-time clock. Similarly, it handles pump cycling in water treatment skids, where the 8 A relay outputs drive contactors directly. In addition, building automation panels use this smart relay for HVAC damper control and access interlocks. The operating temperature range of -20 to 55 °C allows installation in unconditioned cabinets. Consequently, the SR2B121FU delivers engineering-grade precision across diverse environments.

Installation and Integration Notes for the SR2B121FU

Mounting the SR2B121FU follows a straightforward procedure. First, snap the unit onto a 35 mm DIN rail. Next, connect the 100-240V AC supply to the designated terminals. Then, wire the eight digital inputs to field devices and the four relay outputs to loads within the 8 A thermal current limit. Because the LCD and navigation buttons provide local access, you can verify I/O status without a programming terminal.

For communication, the SR2B121FU supports extension modules. If your architecture requires fieldbus connectivity, confirm the appropriate gateway or connection module with the supplier. In addition, verify that extension modules are compatible with the Zelio Logic series before ordering.

Support and Availability

The SR2B121FU is active in production within the Zelio Logic range. AutoDCSTech supplies this smart relay and offers specialist engineering support for configuration and integration questions. Contact AutoDCSTech with your exact requirements for precise matching.