Why the SR3B261BD Belongs in Your Control Cabinet
Machine builders and maintenance teams often face the same problem: a control panel full of discrete timers, relays, and counters that consume space and create wiring headaches. The SR3B261BD from Schneider Electric solves this by combining logic control, timing, counting, and real-time scheduling in a single compact module. As part of the Zelio Logic range, this smart relay delivers 26 I/O points in a housing that measures just 90 × 124.6 × 59.5 mm and weighs 0.30 kg. That small footprint frees up valuable DIN rail space while reducing component count and wiring time.
Inside the Zelio Logic SR3B261BD
The SR3B261BD is a modular smart relay with 16 digital inputs and 10 relay outputs. Six of those inputs are configurable as analog inputs, giving you flexibility for temperature, pressure, or level signals without adding separate analog modules. The 24V DC supply accepts a range of 19.2 to 30V, which means it tolerates the voltage fluctuations common in industrial power distribution. Each relay output handles up to 5 A, enough to drive contactors, solenoid valves, and indicator lamps directly.
An integrated real-time clock enables calendar-based functions such as scheduling, time-stamping, and night setback routines. The LCD screen with navigation buttons lets technicians monitor I/O status and adjust parameters on the panel door without a programming terminal. Program memory supports 240 lines of ladder logic or 500 FBD blocks, covering most small to medium machine control tasks.
Key Specifications at a Glance
| Parameter | Value |
|---|---|
| I/O points | 26 |
| Digital inputs | 16 (6 configurable as analog) |
| Digital outputs | 10 relay |
| Relay output current | 5 A per output |
| Supply voltage | 24V DC (19.2–30V) |
| Operating temperature | -20 to 55 °C |
| Mounting | 35 mm DIN rail |
| Dimensions (H×W×D) | 90 × 124.6 × 59.5 mm |
| Weight | 0.30 kg |
| Mechanical life | 10,000,000 cycles |
| Electrical life | 500,000 cycles (AC-12, 230V 1.5A) |
Replacing Legacy Relays and Timers
Angle D — Replacement and upgrade guide. If your panel still relies on separate timers, counters, and relay banks, the SR3B261BD offers a clean migration path. The 35 mm DIN rail mounting matches standard enclosure hardware, so mechanical installation is straightforward. The 24V DC supply aligns with common control voltages, and the relay outputs can switch the same loads your existing relays handle. Because the SR3B261BD is active in production within the Zelio Logic range, replacement units and expansion modules remain available. Before ordering, verify your existing I/O count, signal types, and panel depth against the dimensions above.
Where the SR3B261BD Performs Best
Small Machine Control
Packaging, labeling, and assembly machines often need 10 to 20 I/O points with timing and counting logic. The SR3B261BD covers these applications with room to spare. The six configurable analog inputs allow simple temperature or pressure monitoring without extra hardware.
Building and Lighting Automation
The integrated real-time clock makes the SR3B261BD suitable for scheduled lighting, HVAC setback, and access control logic. Relay outputs switch lighting circuits and damper actuators directly at 5 A per point.
Pump and Valve Sequencing
Water treatment and process skids benefit from the relay output life ratings. With 10,000,000 mechanical cycles and 500,000 electrical cycles at AC-12, 230V 1.5A, the SR3B261BD handles frequent switching duty in valve and pump control sequences.
Installation and Setup Notes
Mount the SR3B261BD on a 35 mm DIN rail inside an enclosure that maintains the -20 to 55 °C operating range. Keep the LCD visible for operators who need to check status or adjust setpoints. Use the navigation buttons to configure basic parameters, or connect a programming cable for ladder and FBD development. For network integration, the SR3B261BD communicates through extension modules such as Ethernet SR3NET01BD or RS485. Confirm your network requirements before selecting expansion hardware.
Maintenance and Long-Term Reliability
Relay outputs are the primary wear point in any smart relay. The 10,000,000 mechanical and 500,000 electrical cycle ratings give maintenance planners a basis for preventive replacement schedules. Inspect terminal connections periodically for tightness and signs of heat. Keep the enclosure free of conductive dust and moisture. Because the SR3B261BD remains active in the Zelio Logic range, spare units and expansion modules stay available for long-term support.
Compatibility and Integration
The SR3B261BD integrates with Zelio Logic expansion modules for additional I/O and communication. Ethernet SR3NET01BD and RS485 options connect the relay to supervisory systems, HMIs, and SCADA networks. The 24V DC input architecture matches IEC 61131-2 Type 1 signal levels, simplifying interface with sensors, pushbuttons, and proximity switches.
What to Verify Before You Buy
Check your required I/O count, input signal types, and output load currents against the specifications above. Confirm panel depth accommodates the 59.5 mm housing. If you need network communication, plan for the appropriate extension module. SpareTechPLC supplies the SR3B261BD and related Zelio Logic components. Contact the team to confirm current availability and lead times.
Frequently Asked Questions
Can the SR3B261BD inputs accept analog signals?
Yes. Six of the 16 digital inputs are configurable as analog inputs, allowing direct connection of analog sensors without additional modules.
What is the maximum current per relay output?
Each of the 10 relay outputs handles up to 5 A, suitable for contactors, solenoids, and indicator lamps.
Does the SR3B261BD include a real-time clock?
Yes. An integrated real-time clock supports scheduling, time-stamping, and calendar-based control functions.
How much program memory does the SR3B261BD offer?
The controller supports 240 lines of ladder logic or 500 function block diagram (FBD) blocks.
Is the SR3B261BD still in production?
Yes. The SR3B261BD is active in the Zelio Logic range. Verify current availability with SpareTechPLC before ordering.
