During technical comparisons, ELECTRIC-SR2B121B appears alongside Schneider VFD, Phoenix Slim Relay and Schneider Electric so engineers assess signal types, ingress protection, and ambient tolerances accurately.
SR2B121B: Schneider Logic Compact Smart Relay
| Brand | Schneider |
| Product Type | Programmable Logic Controller (PLC) |
| Product | SR2B121B |
Schneider Logic Compact Smart Relay SR2B121B Technical Specifications:
| Specification | Value |
|---|---|
| Cycle time | 6…90 ms |
| Isolation voltage | 1780 V |
| Supply voltage limits | 20.4…28.8 V |
| Discrete input frequency | 57...63 Hz47...53 Hz |
| Maximum supply current | 145 mA (without extension) |
| Electrical durability | AC-12: 500000 cycles at 230 V, 1.5 A for relay output conforming to IEC 60947-5-1AC-15: 500000 cycles at 230 V, 0.9 A for relay output conforming to IEC 60947-5-1DC-12: 500000 cycles at 24 V, 1.5 A for relay output conforming to IEC 60947-5-1DC-13: 500000 cycles at 24 V, 0.6 A for relay output conforming to IEC 60947-5-1 |
| Power consumption in VA | 4 VA without extension |
| Output voltage limits | 5...30 V DC (relay output)24...250 V AC |
| Switching capacity in mA | >= 10 mA at 12 V (relay output) |
| Product or component type | Compact smart relay |
| Counting Frequency | - |
| Protection type | Against inversion of terminals (control instructions not executed) |
| [Us] rated supply voltage | 24 V AC |
| Input impedance | 4.6 kOhm for discrete input |
| Discrete input current | 4.4 mA |
| Operating rate in Hz | 0.1 Hz (at Ie) for relay output10 Hz (no load) for relay output |
| Connections - terminals | Screw terminals, 1 x 0.2...1 x 2.5 mm² (AWG 25...AWG 14) semi-solidScrew terminals, 1 x 0.2...1 x 2.5 mm² (AWG 25...AWG 14) solidScrew terminals, 1 x 0.25...1 x 2.5 mm² (AWG 24...AWG 14) flexible with cable endScrew terminals, 2 x 0.2...2 x 1.5 mm² (AWG 24...AWG 16) solidScrew terminals, 2 x 0.25...2 x 0.75 mm² (AWG 24...AWG 18) flexible with cable end |
| Discrete input type | - |
| Range of product | Zelio Logic |
| Overvoltage category | III conforming to IEC 60664-1 |
| Current state 1 guaranteed | >= 2 mA (discrete input) |
| Number of outputs | 4 relay |
| Reverse polarity protection | - |
| Ambient air temperature for operation | -20…40 °C in non-ventilated enclosure conforming to IEC 60068-2-1 and IEC 60068-2-2-20…55 °C conforming to IEC 60068-2-1 and IEC 60068-2-2 |
| Power dissipation in W | - |
| Output thermal current | 8 A for all 4 outputs for relay output |
| Supply frequency | 50/60 Hz |
| Operating altitude | 2000 m |
| Input compatibility | - |
| Net weight | 0.25 kg |
| Discrete input voltage | 24 V AC |
| Tightening torque | 0.5 N.m |
The Schneider SR2B121B operates on a rated supply voltage of 24V AC with a stable supply range of 20.4V to 28.8V, consuming a maximum current of 145 mA without extension. It includes 4 relay outputs with a total output thermal current of 8A, suitable for managing both resistive and inductive loads. The device supports output voltage limits from 5–30V DC and 24–250V AC, making it versatile for mixed-signal environments.
With a cycle time between 6 to 90 ms and high isolation voltage of 1780V, the SR2B121B is built for reliability in challenging conditions. It features an input impedance of 4.6 kΩ, discrete input current of 4.4 mA, and is compatible with 24V AC discrete input signals. The product supports a switching capacity of ≥10 mA at 12V and delivers consistent operation across -20°C to +55°C in compliance with IEC 60947-5-1. Certified under Overvoltage Category III and built for use up to 2000 meters altitude, it fits well in both indoor control cabinets and field-level systems where size and dependability matter.
The SR2B121B Compact Smart Relay is ideal for control panels managing motor starters, lighting circuits, water pumps, and basic automation in industries like packaging, textile, and material handling. With 4 relay outputs and universal wiring options, it allows integrators to replace bulky relay logic with a neat, programmable controller.
Field electricians and junior maintenance engineers benefit from its simple screw terminals and clear relay logic, especially when upgrading older systems or troubleshooting frequent relay issues. For OEMs and panel builders, the SR2B121B offers seamless integration and faster commissioning with Schneider’s Zelio Soft software platform.
Whether you're an engineering student working on training kits or a senior technician maintaining process equipment, the Schneider SR2B121B provides a flexible entry point into programmable logic. Its high electrical durability and compact form make it a trusted tool in today’s modern automation cabinets. For detailed technical drawings or ladder diagram support, refer to the official SR2B121B datasheet or manual available on the Schneider Electric portal.
