{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"6EP1931-2FC21","brand":"Siemens","brandSlug":"siemens","productSlug":"6EP1931-2FC21","canonicalUrl":"https://aoctrl.com/siemens/6EP1931-2FC21","factsUrl":"https://aoctrl.com/api/mcp/products/6EP1931-2FC21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SITOP DC UPS module 6EP1931-2FC21, 24 V DC input, 40 A rated current, 960 W active power, with battery backup and signaling contacts.","salesMarkdown":"The Siemens 6EP1931-2FC21 is a DC uninterruptible power supply (UPS) module from the SITOP family, designed to buffer 24 V DC control voltage when the primary supply dips or fails. It accepts 22 to 29 V DC input and delivers up to 40 A continuously, with a peak of 42 A for short periods. Active power is rated at 960 W typical. In normal operation, a green LED signals OK, and a floating changeover contact confirms the input voltage is above the cut-in threshold. When the input drops, the module switches to buffered mode, drawing from an external battery module — a yellow LED and a separate changeover contact indicate battery-active status. Prewarning at battery voltage below 20.4 V DC triggers a red alarm LED and switches the alarm contact. The 40 A rated current is the continuous load the module can support in normal operation; the 42 A peak covers motor inrush or capacitive loads during startup. If your control cabinet draws 35 A steady with occasional spikes, this module holds without tripping. Output voltage follows the formula Vin minus approximately 0.5 V, so with a 24 V DC supply you get about 23.5 V at the load. The startup delay is 1 s typical — the module waits before engaging the output to allow the primary supply to stabilize. Storage and transport tolerate -40 to +85 °C. Snaps onto DIN rail EN 60715 35x7.5/15 — standard 35 mm rail. Enclosure dimensions are 102 mm wide, 125 mm high, 125 mm deep. The top clearance required is 50 mm; left and right clearance is 0 mm, so modules can be butted side-by-side. Bottom clearance is 50 mm for wiring access. Input and output each use two screw terminals accepting 0.33 to 10 mm² (22 to 7 AWG). The signaling contacts are rated for DC 60 V / 1 A or AC 30 V / 1 A — sufficient for driving PLC digital inputs or indicator lamps. Carries CE marking, cULus listing under UL 508 and CSA C22.2 No. 107.1 (File E197259), plus EAC approval. DNV GL and ABS shipbuilding approvals are on file. Emission limits meet EN 55022 Class B; immunity meets EN 61000-6-2. Protection class is IP20.","metaTitle":"Siemens 6EP1931-2FC21 DC UPS Module, 40 A, 960 W","metaDescription":"Siemens 6EP1931-2FC21 DC UPS module, 24 V DC input, 40 A rated, 960 W active power. cULus listed, DNV GL approved. Active production. RFQ for pricing.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"NRND","categoryPath":["DIN Rail Power Supplies"],"specifications":{"Top":"50 mm","Left":"0 mm","Right":"0 mm","Bottom":"50 mm","C-Tick":"No","DNV GL":"Yes","At Input":"24 V DC: 2 screw terminals for 0.33 ... 10 mm²/22 ... 7 AWG","At Output":"24 V DC: 2 screw terminals for 0.33 ... 10 mm²/22 ... 7 AWG","CE marking":"Yes","Rated Value":"40 A","UL approval":"Yes","EAC approval":"Yes","Peak Current":"42 A","During Storage":"-40 ... +85 °C","MTBF at 40 °C":"522 739 h","lifecycle_stage":"current","Charging Current":"1 A, 2 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 ... 40 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":"102 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":"960 W","Type Of Electrical Connection":"screw-type terminals","product component PC interface":"No","For Rechargeable Battery Module":"24 V DC: 2 screw terminals for 0.33 ... 10 mm²/22 ... 7 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. 2 A","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":"360 ms","In Case Of Operation On Rechargeable Battery Typical":"33.6 W","input current at rated input voltage 24 V rated value":"40 A; + approx. 2.6 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":"28.6 W","Reverse Polarity Protection Against Energy Storage Unit Polarity Reversal":"Yes"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$277.77","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=82945&mlfb=6EP1931-2FC21","alternativesUrl":"https://aoctrl.com/api/mcp/products/6EP1931-2FC21/alternatives.json"},"ai":{"faq":[{"question":"What compliance documentation does this module carry?","answer":"It has CE marking, cULus listing (UL 508, CSA C22.2 No. 107.1), EAC approval, and shipbuilding approvals from DNV GL and ABS. Emissions comply with EN 55022 Class B; immunity with EN 61000-6-2."},{"question":"What are the mounting clearance requirements?","answer":"Top clearance is 50 mm, bottom clearance is 50 mm. Left and right clearance is 0 mm, allowing side-by-side mounting on DIN rail."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/6EP1931-2FC21","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/6EP1931-2FC21 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}