{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"6ES7921-5CK20-0AA0","brand":"Siemens","brandSlug":"siemens","productSlug":"6ES7921-5CK20-0AA0","canonicalUrl":"https://aoctrl.com/siemens/6ES7921-5CK20-0AA0","factsUrl":"https://aoctrl.com/api/mcp/products/6ES7921-5CK20-0AA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIMATIC S7-1500, Front connector module, 6ES7921-5CK20-0AA0, 40-pole IDC connector for analog I/O, 24 V rated, direct mounting, 30 m max cable length.","salesMarkdown":"## What this front connector module does in an S7-1500 rack The Siemens 6ES7921-5CK20-0AA0 is a front connector module that bridges the 50-pole IDC cable from a terminal module to the 40-pole front connector of an analog I/O module in a SIMATIC S7-1500 system. It carries the 24 V rated supply and analog signals between the field wiring and the I/O module, with a maximum cable run of 30 m between the front connector module and the terminal module. The 40-pole front connector mates directly to analog I/O modules, while the 50-pole IDC connector on the first interface accepts the pre-assembled connection cable from the terminal block. This keeps the field wiring termination separate from the module slot, so you can swap I/O modules without disturbing the field cables. Mounts directly onto the S7-1500 I/O module — no DIN rail required for this component itself. The terminal position is at the top of the module, which keeps the wiring accessible when the module is installed in a panel. Operating temperature range is 0 to 60 °C, storage from -40 to +70 °C, with pollution degree 2 and overvoltage category II — suitable for standard industrial control cabinet environments. The insulating body material is specified as 'other' (not standard thermoplastic), and the enclosure is black. The module is not transparent, and no end cover plate is required for this component. ## Wiring and connection details The front connector accepts up to two conductors per connection point, with the voltage supply routed through the infeed element of the module. A 3.5 mm screwdriver blade width is specified for the screw terminals. Solid conductors are not supported — use flexible conductors with core-end processing (ferrules). The connection cable uses a plug-in IDC connector at the module end.","metaTitle":"Siemens 6ES7921-5CK20-0AA0 Front Connector Module, 40-Pole,","metaDescription":"Siemens 6ES7921-5CK20-0AA0 front connector module for SIMATIC S7-1500 analog I/O. 40-pole IDC connector, 24 V rated, 30 m max cable. Active production, sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["PLC Accessories"],"specifications":{"Rated Value":"24 V","Mounting Type":"direct mounting","Target System":"SIMATIC S7-1500","During Storage":"-40 ... +70 °C","Number Of Poles":"40; of the front connector","at DC / maximum":"60 V","lifecycle_stage":"mature","During Operation":"0 ... 60 °C","Degree Of Pollution":"2","Product Designation":"Front connector module","Suitability For Use":"Analog I/O modules","at DC / rated value":"24 V","Overvoltage Category":"2","Operating Temperature":"0 ... 60 °C","Wire Length / Maximum":"30 m; between front connector module and terminal module","Color / Of The Enclosure":"black","Position / Of The Terminal":"at the top","Width Of Screwdriver Blade":"3.5 mm","Product Feature / Transparent":"No","Material / Of The Insulating Body":"other","Number Of Cables / Per Connection":"2; Connection for internal system: Combination of 1 or 2 Wires until the sum total of cross sections be achieved in a ferrule.","Number Of Poles / At The 1st Interface":"50; the IDC connector for the connection cable","reference code / according to IEC 81346-2":"XG","Product Component / Required / End Cover Plate":"No","design tested acc. to type of protection / EEx e":"No","For Flexible Conductor / With Core End Processing":"voltage supply via feed element of the module","Type Of Connectable Conductor Cross-Sections / Solid":"No","Type Of Electrical Connection / For Connecting Cable":"Plug-in connection","Number Of The Plug Contacts / Of The Electrical Connection":"1"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$40.64 – $104.00","priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/6d57f154fff616166253fab8c566f5cb.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=417101&mlfb=6ES7921-5CK20-0AA0","alternativesUrl":"https://aoctrl.com/api/mcp/products/6ES7921-5CK20-0AA0/alternatives.json"},"ai":{"faq":[{"question":"What is 6ES7921-5CK20-0AA0's rated voltage?","answer":"The rated voltage is 24 V DC, with a maximum DC voltage of 60 V."},{"question":"What is the maximum cable length between the front connector module and the terminal module?","answer":"30 meters maximum between the front connector module and the terminal module."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/6ES7921-5CK20-0AA0","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/6ES7921-5CK20-0AA0 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}}