schneider-electric
Schneider Electric Zelio Logic Smart Relay
Model: SR2B121BD
4-hour response · Pricing in SAR · Delivery across all KSA regions
SR2B121BD — Schneider Electric Zelio Logic Smart Relay
The Schneider Electric Zelio Logic SR2/SR3 smart relay is a compact programmable control device covering 10 to 26 I/O points in a single DIN-rail-mounted unit, designed to replace conventional contactor and timer relay wiring for simple automation tasks in building services, machinery, and light industrial applications without the complexity and cost of a full PLC system. The Zelio SR2 (10 I/O) and SR3 (26 I/O) are programmed using Zelio Soft PC software or the built-in front panel keypad, supporting ladder diagram (LD) and function block diagram (FBD) programming languages with a library of standard function blocks including timers, counters, comparators, PID controllers, and communication blocks that cover the control requirements of most simple automation tasks.
The Zelio Logic's integrated LCD display with backlight provides local monitoring of input/output states and analog values, enabling operators and maintenance technicians to observe machine status and diagnose faults without additional instruments. The built-in RS485 Modbus RTU communication port (on SR3 models) connects the Zelio to HMI displays, SCADA systems, and supervisory PLCs without additional communication hardware, enabling Zelio to serve as a field intelligence node in a distributed control architecture. Zelio SR3 models offer 4 analog inputs for temperature, pressure, and level sensors, enabling closed-loop control of simple process variables without a separate PLC.
In Saudi Arabia, the Zelio Logic KSA is the standard solution for small building services automation tasks including pump alternation, level control, pressure regulation, and ventilation sequencing where a full PLC is over-engineered and traditional relay-timer wiring is inflexible. Building services contractors across Riyadh, Jeddah, and Dammam use Zelio in pump house control panels for duplex pump alternation with overflow and dry-run protection. OEM equipment suppliers use Zelio for small packaged equipment control including air compressors, water softeners, dosing systems, and filter press automation. Agricultural irrigation control panels use Zelio SR3 with analog inputs for soil moisture sensor feedback and zone timer control.
Razz Middle East stocks Zelio Logic SR2 and SR3 in 24 V DC and 100–240 V AC power supply versions for immediate delivery, with Zelio Soft software and application programming support for panel builders and OEM equipment suppliers across Saudi Arabia.
Technical Specifications
Full specifications for the SR2B121BD
- I/O Points
- 10 (SR2) / 26 (SR3)
- Analog Inputs
- 4 (SR3 models)
- Programming
- Ladder (LD) + FBD via Zelio Soft / front panel
- Display
- Backlit LCD
- Communication
- Modbus RTU RS485 (SR3)
- Function Blocks
- Timers, counters, comparators, PID, clock
- Power Supply
- 24 V DC or 100–240 V AC
- Mounting
- DIN rail 70–90 mm width
Key Features & Benefits
- 10 to 26 I/O in a single DIN rail unit replaces complex relay-timer wiring diagrams for simple automation tasks, reducing panel wiring labour time by 50–70% compared to equivalent discrete relay logic.
- Front panel keypad and LCD display allow programme creation and monitoring without a PC, enabling panel builders and site technicians to create and modify control logic without a laptop on-site.
- Modbus RTU communication in SR3 models connects Zelio to Harmony HMI panels, supervisory PLCs, and SCADA systems, enabling small smart relay nodes to report status and receive setpoints over a shared Modbus network.
- Built-in real-time clock with weekly and seasonal programmable schedules enables time-based control of lighting, ventilation, and irrigation systems without external timer modules.
- Four analog inputs in SR3 models accept 0–10 V and 0–20 mA signals from temperature, pressure, level, and flow sensors, enabling closed-loop process control for simple applications without a separate PLC.
- Zelio Soft simulation function tests programme logic on the PC before download, catching logical errors before panel commissioning and reducing site debugging time for new programme development.
- Parameter storage and programme upload/download via front panel or PC USB preserves programme backup and enables rapid programme restore after device replacement, minimising downtime for small automation control panel maintenance.
Industrial Applications in Saudi Arabia
- Duplex pump alternation control panels in building services plant rooms across Saudi commercial buildings, where Zelio SR2 provides lead/lag alternation, run-time equalisation, and high-level alarm without a full PLC.
- Water tank level control panels for overhead and underground tanks in residential compounds and commercial buildings, where Zelio SR3 with analog level input manages fill and pump stop sequences automatically.
- Ventilation system sequencing in industrial facilities and warehouses, where Zelio controls fan start/stop sequences, temperature setpoint control, and CO sensor interlocking without full PLC infrastructure.
- Air compressor control panels for small packaged compressors in workshops and light industrial facilities, where Zelio manages pressure setpoint control, auto-restart, and hour meter reporting.
- Agricultural irrigation zone control in Saudi landscaping and farming projects, where Zelio SR3 with soil moisture analog inputs manages irrigation zone timing and real-time feedback control.
- Water treatment dosing system control for small chlorination and pH adjustment applications at NWC rural water supply installations, where Zelio SR3's analog inputs receive residual chlorine and pH sensor signals.
- Small packaged equipment OEM control including water softeners, UV sterilisers, and filtration systems where Zelio provides cycle sequencing, fault alarm output, and Modbus status reporting to building management systems.
Industrial Supplier in Saudi Arabia
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Frequently Asked Questions — SR2B121BD
Common questions from buyers in Saudi Arabia and the GCC