{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"6ES7521-7BH00-0AB0","brand":"Siemens","brandSlug":"siemens","productSlug":"6ES7521-7BH00-0AB0","canonicalUrl":"https://aoctrl.com/siemens/6ES7521-7BH00-0AB0","factsUrl":"https://aoctrl.com/api/mcp/products/6ES7521-7BH00-0AB0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIMATIC S7-1500 digital input module, 16 DI at 24 V with 32-bit counter and oversampling, order code 6ES7521-7BH00-0AB0.","salesMarkdown":"## What you're slotting into the rack The Siemens 6ES7521-7BH00-0AB0 is a SIMATIC S7-1500 digital input module: 16 inputs at a 24 V rated value, with MSI support and a P-reading source/sink input characteristic on each channel. It is not a plain DI — the module carries a 32-bit counting width, hardware and software gate start/stop, and a minimum resolution of 15.625 µs, which is why the 7BH00 suffix gets pulled into a BOM instead of a basic high-feature DI. Footprint is the standard S7-1500 slice: 35 mm wide, 147 mm tall, 129 mm deep, approximately 240 g, drawing about 7 W of backplane power loss under typical load. ## Counting and oversampling — the reason it isn't a 1BH00 Beyond a 24 V digital input with wire-break detection down to I < 350 µA, the module is parameterizable for pulse extension in six steps (0.05 / 0.1 / 0.2 / 0.5 / 1 / 2 s) and supports both positive and negative edge evaluation. Oversampling is enabled on the module, isochronous mode is supported, and the firmware version field reads V1.0.0 with field-update capability — relevant if the rack is being modernized against an existing TIA Portal project. ## Signal levels, timing, and cable runs Input thresholds are the standard S7-1500 24 V DI curve: signal '1' is recognized between +11 and +30 V, signal '0' between -30 and +5 V. Edge-to-edge timing spans 0.05 ms minimum to 20 ms maximum in both directions, so the same channel can serve a fast counter and a debounced limit switch. Cable runs are governed by the input frequency and shielding: up to 1 000 m shielded (600 m when used for technological functions), 600 m unshielded for plain DI use, and 50 m is the published ceiling at 20 kHz on the counter channels. ## Diagnostics, identification, and panel-side reading The module carries a green RUN LED, a red ERROR LED, a diagnostic alarm, hardware interrupt capability, and I&M0 through I&M3 identification data — the level of asset-tag and alarm reporting expected of an S7-1500 slice. Two-wire sensors are supported; short-circuit to the supply is not a published diagnostic on this module, so protect the field wiring externally if the cabinet layout exposes the run to a chafe path. Lifecycle stage is recorded as current, so the module remains in normal production rather than being NRND or discontinued.","metaTitle":"Siemens 6ES7521-7BH00-0AB0 DI module, 16 DI 24 V","metaDescription":"Siemens 6ES7521-7BH00-0AB0 S7-1500 digital input module, 16 inputs at 24 V with 32-bit counter and oversampling, current production. Sourced to order against an RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["PLC Communication Modules"],"specifications":{"DI":"Yes","MSI":"Yes","24 V":"Yes","Depth":"129 mm","Width":"35 mm","title":"6ES7521-7BH00-0AB0","Height":"147 mm","Counter":"Yes","RUN LED":"Yes; green LED","I&M data":"Yes; I&M0 to I&M3","ERROR LED":"Yes; red LED","Wire-break":"Yes; to I < 350 µA","description":"SIMATIC S7-1500, digital input module DI 16x24 V DC AUX; 16 channels in groups of 8; for 24 V encoder; sensor supply 24 V DC; input type 2 (IEC 61131); input delay parameterizable 0.05..20 ms; isochronous mode up to 250 µs; integrated counting function up to 20 kHz; pulse stretching; chatter monitoring; signal inversion diagnostics; hardware interrupts: front connector (screw terminals or push-in) and, if applicable, order shield set separately","Number, max.":"16","Oversampling":"Yes","2-Wire Sensor":"Yes","Short-circuit":"No","Counting width":"32 bit","For Signal \"0\"":"-30 to +5 V","For Signal \"1\"":"+11 to +30V","Shielded, Max.":"1 000 m; 600 m for technological functions; depending on input frequency, encoder and cable quality; max. 50 m at 20 kHz","Edge evaluation":"Yes; Positive edge, negative edge","Gate start/stop":"Yes; software/hardware gate","Parameterizable":"Yes","Pulse extension":"Yes; 0.05 s, 0.1 s, 0.2 s, 0.5 s, 1 s, 2 s","Weight, approx.":"240 g","lifecycle_stage":"current","Diagnostic alarm":"Yes","Firmware version":"V1.0.0","Isochronous mode":"Yes","Power loss, typ.":"7 W","Rated value (DC)":"24 V","Resolution, min.":"15.625 µs","Unshielded, Max.":"600 m; for technological functions: No","Number of outputs":"16; 2x 24 V DC","Source/sink input":"P-reading","FW update possible":"Yes","Hardware interrupt":"Yes","At \"0\" To \"1\", Max.":"20 ms","At \"0\" To \"1\", Min.":"0.05 ms","At \"1\" To \"0\", Max.":"20 ms","At \"1\" To \"0\", Min.":"0.05 ms","Prioritized startup":"Yes","Between The Channels":"No","Diagnostics function":"Yes","For Signal \"1\", Typ.":"9 mA","HW functional status":"From FS01","Output current, max.":"150 mA; per group","Isolation tested with":"707 V DC (type test)","Signal change flutter":"Yes; 2 to 32 signal changes","Channel status display":"Yes; green LED","For Module Diagnostics":"Yes; red LED","Values per cycle, max.":"16","For Channel Diagnostics":"Yes; red LED","Counting frequency, max.":"20 kHz","Number of digital inputs":"16","Short-circuit protection":"Yes; Per group, electronic","Current consumption, max.":"550 mA","Bus cycle time (TDP), min.":"250 µs","Counting direction up/down":"Yes","Flutter observation window":"Yes; 0.5 s, 1 s to 100 s in 1-s steps","Freely usable digital input":"Yes","Reverse polarity protection":"Yes","Vertical Installation, Max.":"40 °C","Vertical Installation, Min.":"-30 °C","Horizontal Installation, Max.":"60 °C","Horizontal Installation, Min.":"-30 °C","Monitoring the supply voltage":"Yes","Suitable for safety functions":"No","Digital input with oversampling":"Yes","Digital inputs, parameterizable":"Yes","Output current per module, max.":"300 mA","Between The Channels, In Groups Of":"8","Monitoring of encoder power supply":"Yes; short-circuit","permissible range, lower limit (DC)":"19.2 V","permissible range, upper limit (DC)":"28.8 V","Between The Channels And Backplane Bus":"Yes","PROFIBUS from GSD version/GSD revision":"V1.0 / V5.1","PROFINET from GSD version/GSD revision":"V2.3 / -","Power available from the backplane bus":"0.6 W","Between the channels and load voltage L+":"Yes","Filtering and processing time (TCI), min.":"60 µs; At 50 μs filter time","Monitoring of the supply voltage (PWR-LED)":"Yes; green LED","Installation altitude above sea level, max.":"5 000 m; Restrictions for installation altitudes > 2 000 m, see manual","STEP 7 configurable/integrated from version":"V5.5 SP3 / -","Permissible Quiescent Current (2-Wire Sensor), Max.":"2 mA","STEP 7 TIA Portal configurable/integrated from version":"STEP 7 V17 or higher","Between The Channels And The Power Supply Of The Electronics":"No"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$228.60","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/14c41e98e3c9060d5154d8dc52b8ed94.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=1550836&mlfb=6ES7521-7BH00-0AB0"},"ai":{"faq":[{"question":"What counting capability does 6ES7521-7BH00-0AB0 have on board?","answer":"It carries a 32-bit counting width, software and hardware gate start/stop, positive and negative edge evaluation, six selectable pulse-extension steps from 0.05 s to 2 s, and a minimum resolution of 15.625 µs, with oversampling and isochronous mode supported."},{"question":"How far can I run cable to 6ES7521-7BH00-0AB0?","answer":"Up to 1 000 m shielded (600 m when used for technological functions), 600 m unshielded for plain DI use, and 50 m at 20 kHz on the counter channels."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/6ES7521-7BH00-0AB0","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/6ES7521-7BH00-0AB0 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}}