{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"6ES7221-1BH22-0XA0","brand":"Siemens","brandSlug":"siemens","productSlug":"6ES7221-1BH22-0XA0","canonicalUrl":"https://aoctrl.com/siemens/6ES7221-1BH22-0XA0","factsUrl":"https://aoctrl.com/api/mcp/products/6ES7221-1BH22-0XA0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIMATIC S7-200 EM 221 digital input module, 6ES7221-1BH22-0XA0, 16 digital inputs, 24 V DC, sinking/sourcing, optocoupler isolation, 62 mm depth, 71.2 mm width, 80 mm height.","salesMarkdown":"## What this EM 221 module is for The Siemens 6ES7221-1BH22-0XA0 is a SIMATIC S7-200 EM 221 digital input expansion module, designed exclusively for S7-22X CPUs. It adds 16 discrete inputs to the base controller, accepting 24 V DC signals in either sinking or sourcing configuration — so it handles both NPN and PNP field devices without rewiring the common rail. Each input channel draws a typical 4 mA at the \"1\" signal level, with a guaranteed ON threshold of +15 to +30 V DC and an OFF threshold of 0 to 5 V DC. The 4.5 ms max transition time from 0-to-1 filters contact bounce and slow sensor edges, but it also sets the minimum detectable pulse width — a fast encoder or proximity switch running above ~110 Hz may be missed without a faster input module. ## Isolation and wiring notes Channel groups of 4 are optically isolated from each other and from the backplane bus, tested at 500 V AC for one minute. This means a short on one group won't pull down the others — useful when mixing 24 V sensors from different power supplies on the same module. The module accepts 2-wire proximity sensors with a max permissible quiescent current of 1 mA — above that the sensor's own leakage may be read as a false \"1\". Plug-in I/O terminals simplify replacement without disconnecting field wiring. Maximum cable runs are 500 m shielded, 300 m unshielded — adequate for most machine-mounted sensor clusters but tight for a distributed fieldbus topology where sensors sit 100+ m from the cabinet. Siemens lists this module at a current lifecycle stage — still supported for existing S7-200 installations but not a design-in for new machines. The S7-200 platform has been superseded by the S7-1200 and S7-1500 families, which use different form factors and backplane protocols. For a line running an S7-22X CPU, this EM 221 is the correct spare. No pin-compatible direct replacement exists in the newer S7-1200 range — a CPU swap and rewiring would be required to migrate.","metaTitle":"Siemens 6ES7221-1BH22-0XA0 EM 221, 16 DI, 24 V DC","metaDescription":"Siemens 6ES7221-1BH22-0XA0 SIMATIC S7-200 EM 221 digital input module, 16 inputs, 24 V DC, sinking/sourcing. Current lifecycle stage. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Digital Input Modules"],"specifications":{"Depth":"62 mm","Width":"71.2 mm","title":"6ES7221-1BH22-0XA0","Height":"80 mm","description":"***Spare part*** SIMATIC S7-200, Digital input EM 221, only for S7-22X CPU, 16 DI, 24 V DC, sinking-sourcing","2-Wire Sensor":"Yes","For Signal \"0\"":"0 to 5 V","For Signal \"1\"":"+15 to +30 V","Shielded, Max.":"500 m","Weight, approx.":"160 g","lifecycle_stage":"current","Power loss, typ.":"3 W","Rated value (DC)":"24 V","Unshielded, Max.":"300 m","Source/sink input":"Yes","At \"0\" To \"1\", Max.":"4.5 ms","For Signal \"1\", Typ.":"4 mA","Isolation tested with":"500V AC for 1 minute","Plug-in I/O terminals":"Yes","Type of input voltage":"DC","Number of digital inputs":"16","from backplane bus 5 V DC, max.":"70 mA","Between The Channels, In Groups Of":"4","Potential separation digital inputs":"Yes; Optocoupler","Permissible Quiescent Current (2-Wire Sensor), Max.":"1 mA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$175.26 – $232.00","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/4244e6711ca4776ca4f58c20846e85d2.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=79379&mlfb=6ES7221-1BH22-0XA0"},"ai":{"faq":[{"question":"Where can I buy 6ES7221-1BH22-0XA0 and how do I get a price?","answer":"This module is sourced to order through independent distribution channels."},{"question":"What is the closest alternative to 6ES7221-1BH22-0XA0 in the S7-200 family?","answer":"Within the S7-200 platform, the EM 221 is the only 16-input 24 V DC expansion module. No pin-compatible alternative exists in newer Siemens families — migration requires a CPU change and rewiring."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/6ES7221-1BH22-0XA0","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/6ES7221-1BH22-0XA0 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}}