{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SR2B121BD","brand":"Schneider Electric","brandSlug":"schneider","productSlug":"SR2B121BD","canonicalUrl":"https://aoctrl.com/schneider/SR2B121BD","factsUrl":"https://aoctrl.com/api/mcp/products/SR2B121BD","rawCanonicalId":null},"summary":{"shortDescription":"Schneider Electric Zelio Logic compact smart relay, 24 V DC, 8 discrete inputs, relay outputs, built-in real-time clock.","salesMarkdown":"## Compact smart relay with RTC and program integrity check The SR2B121BD is a Schneider Zelio Logic compact smart relay running at 24 VDC, packing 8 discrete inputs per IEC 61131-2 Type 1 and relay outputs. It carries a built-in real-time clock (: Clock: With) that is battery-backed for 10 years at 77 °F (: Backup time). On each power-up the unit runs a program memory check (: Checks: Program memory on each power up) to verify the ladder/FBD logic hasn't corrupted. Cycle time spans 6...90 ms, adequate for most conveyor, pump, or light-curtain sequences. Response time from input transition to relay output is 10 ms for 0→1 and 5 ms for 1→0. Discrete inputs are resistive type, 4 mA at 24 VDC, and the unit draws under 100 mA without expansion modules. Relay outputs are rated for a mechanical durability of 10 million cycles, but the maximum operating rate is 0.1 Hz at rated current (Ie) and 10 Hz at no load. That matters if you're switching a contactor coil at high speed — stay within the 0.1 Hz limit under load to avoid premature weld. Environment: Pollution degree 2, overvoltage category III, IP20 on terminals and IP40 on front panel. It withstands the IEC immunity suite — levels 3 for fast transients and ESD, plus surge and conducted RF. Disturbance radiated/conducted is Class B, group 1, so it's fine for residential/commercial panels, not just industrial zones. Supply voltage limits are 19.2...30 V on the nominal 24 VDC rail, with reverse polarity protection. Power dissipation stays at 3 W without extension. Screw terminals accept 1 x 0.2 to 2.5 mm² solid or stranded, and tightening torque is 0.5 N·m. ## Compliance documentation The SR2B121BD is designed to meet IEC 61131-2 (programmable controllers), IEC 61000-6-2/3/4 (EMC), and Low Voltage Directive. It also carries IEC 60068 vibration/shock ratings. RoHS/REACH declarations are available upon request; these are not in the standard spec publication but are part of the Schneider compliance pack for active catalog items.","metaTitle":"Schneider SR2B121BD Zelio Logic Smart Relay, 24 VDC, RTC","metaDescription":"Active Zelio Logic compact smart relay, 8 DI 24VDC, relay outputs, real-time clock with 10-year backup. Complies IEC 61131-2. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":[],"specifications":{"Clock":"With","Checks":"Program memory on each power up","Category":"US1000I22378","Standards":"IEC 61000-4-12 IEC 61000-4-4 level 3 IEC 61000-4-5 IEC 61000-4-11 IEC 61000-4-2 level 3 IEC 60068-2-6 Fc IEC 61000-4-6 level 3 IEC 60068-2-27 Ea IEC 61000-4-3","Cycle time":"6...90 ms","Backup time":"10 years 77 °F (25 °C)","Clock drift":"12 min/year 32...131 °F (0...55 °C) 6 s/month 77 °F (25 °C)","Local display":"With","Response time":"10 ms from state 0 to state 1)relay output 5 ms from state 1 to state 0)relay output","lifecycle_stage":"current","Pollution degree":"2 IEC 61131-2","Range of Product":"Zelio Logic","Relative Humidity":"95 % without condensation or dripping water","Tightening Torque":"4.4 lbf.in (0.5 N.m)","Counting frequency":"1 kHz discrete input","Operating altitude":"6561.68 ft (2000 m)","Discrete input type":"Resistive","Operating rate in Hz":"0.1 Hz at Ie)relay output 10 Hz no load)relay output","Overvoltage category":"III conforming to IEC 60664-1","Discrete input number":"8 IEC 61131-2 Type 1","Mechanical durability":"10000000 cycles relay output","Nbr. of units in pkg.":"1","Supply voltage limits":"19.2...30 V","Discrete input current":"4 mA","Discrete input voltage":"24 V DC","Maximum supply current":"100 mA without extension)","Power dissipation in W":"3 W without extension","Connections - terminals":"Screw terminals, 1 x 0.2...1 x 2.5 mm² AWG 25...AWG 14) semi-solid Screw terminals, 1 x 0.2...1 x 2.5 mm² AWG 25...AWG 14) solid Screw terminals, 1 x 0.25...1 x 2.5 mm² AWG 24...AWG 14) flexible with cable end Screw terminals, 2 x 0.2...2 x 1.5 mm² AWG 24...AWG 16) solid Screw terminals, 2 x 0.25...2 x 0.75 mm² AWG 24...AWG 18) flexible with cable end","IP degree of protection":"IP20 IEC 60529 terminal block) IP40 IEC 60529 front panel)","Immunity to microbreaks":"1 ms","Product or Component Type":"Compact smart relay","[Us] rated supply voltage":"24 V DC","Current state 0 guaranteed":"= 10 mA 12 V relay output)","Maximum altitude transport":"10000 ft (3048 m)","Voltage state 0 guaranteed":"= 1.2 mA IB...IG used as discrete input circuit) >= 2.2 mA I1...IA and IH...IR discrete input circuit)","Voltage state 1 guaranteed":">= 15 V I1...IA and IH...IR discrete input circuit >= 15 V IB...IG used as discrete input circuit","Reverse polarity protection":"With","Environmental characteristic":"EMC directive conforming to IEC 61000-6-2 EMC directive conforming to IEC 61000-6-3 EMC directive conforming to IEC 61000-6-4 EMC directive conforming to IEC 61131-2 zone B Low voltage directive conforming to IEC 61131-2","Disturbance radiated/conducted":"Class B EN 55022-11 group 1","Number or control scheme lines":"0...240 ladder 0...500 FBD","Ambient Air Temperature for Storage":"-40...158 °F (-40...70 °C)","Ambient air temperature for operation":"-4...104 °F (-20...40 °C) in non-ventilated enclosure IEC 60068-2-1 and IEC 60068-2-2 -4...131 °F (-20...55 °C) IEC 60068-2-1 and IEC 60068-2-2","[Uimp] rated impulse withstand voltage":"4 kV EN/IEC 60947-1 and EN/IEC 60664-1"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$78.74","priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/adeb5de1adc1be082fcab3367d9a6646.pdf","sourceUrl":null,"alternativesUrl":"https://aoctrl.com/api/mcp/products/SR2B121BD/alternatives.json"},"ai":{"faq":[{"question":"What is SR2B121BD's listed clock specification?","answer":"The unit includes a real-time clock (: Clock: With). Backup time is 10 years at 77 °F (25 °C), and clock drift is 6 s/month at 77 °F."},{"question":"What program integrity checks does SR2B121BD perform?","answer":"On every power-up, it runs a program memory check (: Checks: Program memory on each power up) to verify the stored ladder/FBD logic is uncorrupted before executing the cycle."},{"question":"What compliance standards does SR2B121BD meet?","answer":"It conforms to IEC 61131-2 (programmable controller), IEC 61000-6-2/3/4 (EMC), and Low Voltage Directive. Immunity includes IEC 61000-4-2 level 3, IEC 61000-4-4 level 3, IEC 61000-4-5, IEC 61000-4-11, and IEC 61000-4-6 level 3. Radiated/conducted emissions are Class B, group 1."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/schneider/SR2B121BD","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/schneider/SR2B121BD when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:21:01.794Z","lastPublished":"2026-09-02T08:21:01.794Z","indexable":true}}