{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"6EP1931-2DC21","brand":"Siemens","brandSlug":"siemens","productSlug":"6EP1931-2DC21","canonicalUrl":"https://aoctrl.com/siemens/6EP1931-2DC21","factsUrl":"https://aoctrl.com/api/mcp/products/6EP1931-2DC21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SITOP DC UPS module, 6EP1931-2DC21, 24 V DC, 6 A rated, 144 W, with battery buffering and alarm contacts, snaps onto DIN rail EN 60715.","salesMarkdown":"The Siemens 6EP1931-2DC21 is a DC uninterruptible power supply (UPS) module designed to buffer 24 V DC control circuits when the primary supply drops. It sits between a standard 24 V DC power supply and the load, providing seamless battery-backed ride-through for PLCs, HMIs, and field I/O during line sags or short interruptions. Rated for 6 A continuous output (0...6 A in normal operation) with a peak of 6.3 A, it delivers up to 144 W of buffered power. The output voltage follows the input minus roughly 0.5 V, so the load sees nearly the same rail voltage during normal operation. The module accepts 22...29 V DC input and includes a 1 s startup delay typical, preventing nuisance battery drain during initial power-up. It uses external batteries (not included) as the energy storage medium. Snaps onto standard 35 mm DIN rail per EN 60715 (35x7.5/15). The enclosure measures 50 mm wide, 125 mm deep, and 125 mm high — a compact footprint that fits a single DIN-rail slot, leaving room for adjacent power supplies or breakers. Input uses two screw terminals accepting 1...4 mm² (17...11 AWG); output uses four screw terminals for the same wire range. All connections are at the front, so wiring doesn't require side clearance — the 0 mm left and right clearance spec means it can be mounted flush against other modules. IP20 rated — suitable for clean, dry control cabinets only. Not for washdown or outdoor use without an enclosure. ## Status signals and alarm contacts Contact rating is DC 60 V / 1 A or AC 30 V / 1 A. LED indicators on the front panel show operating state: green for normal, yellow for buffered mode, red for alarm (low battery or battery replacement needed). The alarm LED flashes at roughly 0.25 Hz when battery replacement is required. The prewarning threshold is set at battery voltage below 20.4 V DC, giving the control system time to execute an orderly shutdown before the battery is fully depleted. Carries cULus listing per UL 508 and CSA C22.2 No. 107.1 (File E197259), CE marking, and EAC approval. Also holds shipbuilding approvals from ABS and DNV GL, making it suitable for marine and offshore applications. EMC compliance: emitted interference per EN 55022 Class B (residential/commercial limits), immunity per EN 61000-6-2 (industrial environment). MTBF at 40 °C is rated at 1,085,776 hours — over 120 years mean time between failures under continuous operation at that temperature, reflecting solid-state design with no moving parts.","metaTitle":"Siemens 6EP1931-2DC21 DC UPS Module, 6 A, 144 W, DIN Rail","metaDescription":"Siemens 6EP1931-2DC21 DC UPS module, 6 A rated, 144 W, snaps onto DIN rail. cULus listed, DNV GL approved. Active production. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["DIN Rail Power Supplies"],"specifications":{"Top":"50 mm","Left":"0 mm","Right":"0 mm","title":"6EP1931-2DC21","Bottom":"50 mm","C-Tick":"No","DNV GL":"Yes","At Input":"24 V DC: 2 screw terminals for 1 ... 4 mm²/17 ... 11 AWG","At Output":"24 V DC: 4 screw terminals for 1 ... 4 mm²/17 ... 11 AWG","CE marking":"Yes","Rated Value":"6 A","UL approval":"Yes","description":"SITOP DC UPS module 24 V/6 A uninterruptible power supply without interface input: 24 V DC/6.85 A output: 24 V DC/6 A *Ex approval no longer available*","EAC approval":"Yes","Peak Current":"6.3 A","During Storage":"-40 ... +85 °C","MTBF at 40 °C":"1 085 776 h","lifecycle_stage":"current","Charging Current":"0.2 A, 0.4 A","During Operation":"-25 ... +60 °C; with natural convection","During Transport":"-40 ... +85 °C","Fastening Method":"Snaps onto DIN rail EN 60715 35x7.5/15","In Buffering Mode":"Buffered mode: LED yellow (Bat), floating changeover contact \"OK/Bat\" to setting \"Bat\"; Prewarning battery voltage < 20.4 VDC: LED red (alarm), floating changeover contact \"Alarm/Bat\" to setting \"Alarm\"; Energy storage > 85%: LED green (Bat > 85%), floating NO contact \"Bat > 85\" closed","Other Information":"Specifications at rated input voltage and ambient temperature +25 °C (unless otherwise specified)","In Normal Operation":"0 ... 6 A","Input Voltage Range":"22 ... 29 V DC","as approval for USA":"cULus-Listed (UL 508, CSA C22.2 No. 107.1), File E197259","protection class IP":"IP20","For Normal Operation":"Normal operation: LED green (OK), floating changeover contact \"Bat/OK\" to setting \"OK\" (\"OK\" means: Voltage of the supplying power supply unit is greater than cut-in threshold set at the DC UPS module); Lack of buffer standby: LED red (alarm), floating changeover contact \"Alarm/Bat\" to setting \"Alarm\"; Battery replacement required: LED red (alarm) flashing with approx. 0.25 Hz, floating changeover contact \"Alarm/Bat\" switching with approx. 0.25 Hz; Energy storage > 85%: LED green (Bat > 85%), floating NO contact \"Bat > 85\" closed; Permissible contact current capacity: DC 60 V/1 A or AC 30 V /1 A","Shipbuilding Approval":"ABS, DNV GL","Depth Of The Enclosure":"125 mm","Electrical Accessories":"Battery module","Type Of Energy Storage":"with batteries","Voltage Curve At Input":"DC","Width Of The Enclosure":"50 mm","Design Of The Interface":"without","Height Of The Enclosure":"125 mm","For Emitted Interference":"EN 55022 Class B","For Interference Immunity":"EN 61000-6-2","Formula For Output Voltage":"Vin - approx. 0.5 V","Startup Delay Time Typical":"1 s","Supplied Active Power Typical":"144 W","Type Of Electrical Connection":"screw-type terminals","product component PC interface":"No","For Rechargeable Battery Module":"24 V DC: 2 screw terminals for 1 ... 4 mm²/17 ... 11 AWG","supply voltage at DC rated value":"24 V","Operating Resource Protection Class":"Class III","in buffering mode at DC rated value":"24 V","in normal operation at DC rated value":"24 V","For Control Circuit And Status Message":"10 screw terminals for 0.5 ... 2.5 mm²/20 ... 13 AWG","output voltage in buffering mode at DC":"19 ... 28.5 V","reference code according to IEC 81346-2":"RB","Adjustable Charging Current Maximum Note":"factory setting approx. 0.4 A","Property Of The Output Short-Circuit Proof":"Yes","Galvanic Isolation Between Input And Output":"No","American Bureau of Shipping Europe Ltd. (ABS)":"Yes","environmental category according to IEC 60721":"Climate class 3K3, 5 … 95% no condensation","Design Of The Mains Power Cut Bridging-Connection":"Dependent on connected battery and load current, see selection table battery module and mains buffering times as well as the relevant important information notes!","Voltage Increase Time Of The Output Voltage Typical":"60 ms","In Case Of Operation On Rechargeable Battery Typical":"8 W","input current at rated input voltage 24 V rated value":"6 A; + approx. 0.6 A with empty battery","Adjustable Response Value Voltage For Buffer Connection":"22 ... 25.5 V; Adjustable in 0.5 V increments","Product Feature Of The Enclosure Housing Can Be Lined Up":"Yes","Adjustable Response Value Voltage For Buffer Connection Preset":"22.5 V","Reverse Polarity Protection Against Input Voltage Polarity Reversal":"Yes","At Rated Output Voltage For Rated Value Of The Output Current Typical":"7 W","Reverse Polarity Protection Against Energy Storage Unit Polarity Reversal":"Yes"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$139.70","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/8b874b793c43a5489e4181bffe42ee90.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=92342&mlfb=6EP1931-2DC21"},"ai":{"faq":[{"question":"What approvals does the 6EP1931-2DC21 carry?","answer":"It carries cULus listing (UL 508, CSA C22.2 No. 107.1), CE marking, EAC approval, and shipbuilding approvals from ABS and DNV GL. EMC compliance covers EN 55022 Class B and EN 61000-6-2."},{"question":"What is the physical size and mounting of the 6EP1931-2DC21?","answer":"The enclosure is 50 mm wide, 125 mm deep, and 125 mm high. It snaps onto standard 35 mm DIN rail per EN 60715. No side clearance is needed (0 mm left/right)."},{"question":"What are the key ratings of the 6EP1931-2DC21?","answer":"Rated output current is 6 A continuous (peak 6.3 A), supplying 144 W of buffered power. Input voltage range is 22...29 V DC. Output voltage is input minus approximately 0.5 V. Startup delay is 1 s typical."},{"question":"What status signals does the 6EP1931-2DC21 provide?","answer":"Three floating relay contacts: a changeover for normal/buffered status, a changeover for alarm (low battery or battery replacement), and a normally-open contact for battery charge above 85%. Contact rating is DC 60 V / 1 A or AC 30 V / 1 A. Front-panel LEDs show green (normal), yellow (buffered), red (alarm)."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/6EP1931-2DC21","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/6EP1931-2DC21 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}