Schneider Electric SR3B261BD Zelio SR3 Smart Relay 26 I/O 24 V

SR3B261BD Zelio Logic modular smart relay: what it is and how the code reads

The SR3B261BD is a Schneider Electric product described in the datasheet as: modular smart relay, Zelio Logic SR2 SR3, 26 IO, 24V DC, clock, display, 10 relay outputs. The SR3B261BD is a Zelio Logic modular smart relay, a small programmable device with display, clock, 16 discrete inputs, 10 relay outputs and 24 V DC supply, for simple automation tasks. Seven Star LLC supplies the SR3B261BD in Oman and the GCC as an independent supplier based in Muscat.

Decoding the reference: SR3 is the modular Zelio Logic smart-relay version, B the base unit, 26 the I/O count (16 inputs and 10 outputs), 1 the relay-output version and BD the 24 V DC supply. The datasheet title reads modular smart relay, Zelio Logic SR2 SR3, 26 IO, 24V DC, clock, display, 10 relay outputs.

Technical specifications of the SR3B261BD

How the SR3B261BD runs its program

A smart relay executes a small program, written in function-block diagram or ladder language, each cycle. The datasheet lists a cycle time of 6 to 90 ms and program capacity of 0 to 500 FBD; 0 to 240 ladder control-scheme lines. Program memory is checked on each power-up, and a real-time clock allows time-based control.

The 16 inputs include 6 that can also work as analogue inputs, and the ten relay outputs are normally open, rated as listed. Conversion accuracy is limited, so use dedicated analogue modules for precise measurements.

Where the SR3B261BD fits in small automation

The SR3B261BD can be programmed from the front display for small edits or from a PC with the manufacturer software. It suits pump alternation, ventilation, lighting, doors and simple sequences where a PLC would be oversized.

Related smart relays in the same range include the compact SR2A201BD (20 I/O, no clock according to its datasheet title) and SR2B121BD; the modular SR3 range is chosen when a clock, display and a larger I/O count are needed.

Selection and ordering checklist for the SR3B261BD

• Count inputs and outputs and compare with 16 inputs and 10 relay outputs.
• Supply 24 V DC within the stated limits.
• Relay output current per output and group, and the load type.
• Analogue input needs: accuracy and range.
• Program size: control-scheme lines.
• Need for clock-based functions and backup time.

Installation, commissioning and maintenance of the SR3B261BD

Mount on a DIN rail, wire the 24 V DC supply and inputs and connect loads to the relay outputs with the protection suitable for each load. The unit weighs 0.4 kg. Download or key in the program, test each output with the loads isolated, and set the clock.

Back up the program to a memory cartridge or PC file, label terminals clearly and fit suppression across inductive loads. The relay outputs wear with switching so avoid fast cycling.

Typical applications of the SR3B261BD in Oman and the GCC

The unit serves small pumping stations, ventilation, booster sets, lighting and door control, tank-level sequences and generator auxiliary logic across Oman and the GCC where a full PLC is not justified.

Programming and maintenance notes for the SR3B261BD

Programs for a smart relay are small, but they still deserve documentation. Keep a printed or saved copy of the function-block or ladder diagram, a list of the input and output assignments and the clock settings. When a unit is replaced, the program can be restored from a backup and the clock reset, which takes minutes instead of rebuilding the logic from memory.

Relay outputs have a defined mechanical life of 10000000 cycles relay output and a shorter electrical life under load, so heavily cycled loads such as pump starters should be switched through an interposing contactor or relay rather than directly. Respect the per-output thermal current listed in the datasheet (5 A for 2 outputs relay output; 8 A for 8 outputs relay output) when grouping loads.

Information to send with an RFQ for the SR3B261BD

• Full reference SR3B261BD and quantity
• Input and output requirements
• Supply voltage
• Extension modules and programming accessories
• Delivery location and timing

Site conditions in Oman for the SR3B261BD

Control cabinets in Gulf plants often run hot, because many sit in outdoor kiosks or in rooms where air conditioning is not always reliable. Before you finalise the SR3B261BD, check the permitted ambient range and any derating stated by the manufacturer against the real temperature inside your panel, and leave the recommended spacing around the device so that heat can escape. Long cable runs between the field and the marshalling cabinet are common on large sites, so confirm the signal types, wiring limits and earthing arrangement early in the design.

It also helps to standardise on a small number of part numbers across a project. Keeping a few spare SR3B261BD units on site in Oman shortens recovery time after a fault, and documenting configuration settings makes replacement faster for the maintenance team.

Documents and quotation

A datasheet for this product is attached on this page. It lists the electrical, mechanical and environmental data summarised above.

Send us the part number, quantity and application and we will confirm availability and a quotation. Seven Star LLC is an independent supplier in Muscat and does not represent itself as an official channel of the manufacturer.