Description
Siemens SIMATIC S7‑300 6ES7321-1BH02-0AA0 – SM 321 Digital Input Module for 24 VDC Field Signals
The 6ES7321-1BH02-0AA0 is a SIMATIC S7‑300 SM 321 digital input module, typically used to bring 24 VDC status signals (sensors, pushbuttons, limit switches) cleanly into the PLC. From my experience, it’s a dependable 16‑channel DI card with straightforward diagnostics and the familiar 20‑pin front connector, so panel technicians can swap it in minutes without disturbing field terminations. You might notice that channel status LEDs make loop checks quick during commissioning or maintenance.
Company’s Order Placement Process and Guarantees
- Warranty period: 365 days
- Delivery time: 1 week for in‑stock; no more than one month at the latest
- Payment method: 50% advance payment, full payment for delivery
- Express delivery methods: FedEx, UPS, DHL
- Process: Confirm model and quantity → Proforma Invoice → Advance payment → Functional testing and packing → Final payment → Express shipment with tracking
Key Features
- 16 digital inputs, 24 VDC – A solid choice for standard sensors and panel contacts feeding the S7‑300.
- Channel status LEDs – Visual checks speed up troubleshooting and FAT/SAT loop tests.
- 20‑pin front connector – Keeps existing field wiring intact during card replacement.
- Backplane integration – No separate comms setup; the module is addressed via the S7‑300 rack.
- Industry‑proven build – Works reliably in cabinets with drives and solenoids when grounding and segregation are done properly.
Technical Specifications
| Brand / Model | Siemens SIMATIC S7‑300 – 6ES7321-1BH02-0AA0 (SM 321 DI) |
| HS Code | 853710 (Programmable controller modules) |
| Power Requirements | Supplied via S7‑300 backplane; inputs use a 24 VDC field supply (L+/M) |
| Dimensions & Weight | Approx. 125 × 40 × 120 mm; ~0.25 kg class (standard S7‑300 module size) |
| Operating Temperature | Typically 0…60 °C cabinet ambient for S7‑300 modules |
| Signal Input Type | Digital inputs, 24 VDC; 16 channels (sink/source wiring as per field device) |
| Communication Interfaces | SIMATIC S7‑300 backplane bus; no user Ethernet/serial on module |
| Installation Method | DIN‑rail mounting on S7‑300 rack; 20‑pin front connector to field wiring |
Application Fields
Commonly used wherever clean, reliable 24 VDC status signals are needed:
- Factory automation: sensors, e‑stops (with external safety relays), selector switches
- Process skids: valve limit switches, pump permissives, interlock contacts
- Infrastructure and utilities: MCC status, breaker indications, level/flow switches
- Brownfield S7‑300 expansions or maintenance replacements
Advantages & Value
- Reliability: Stable input behavior with clear channel LEDs—handy during loop checks.
- Compatibility: Native S7‑300 module; no rewiring in most cases when replacing like‑for‑like.
- Cost efficiency: 16 channels per card helps keep I/O density high and cabinet space down.
- Support: We can function‑test inputs and provide a short report (LEDs, scan, and contact debounce) before shipment.
“Swapped a faulty DI card with 6ES7321‑1BH02‑0AA0 during a tight outage. Addressing stayed the same, LEDs made checks easy, and the line was back up fast.” — Maintenance engineer, food & beverage plant
Installation & Maintenance
- Cabinet setup: Mount on the S7‑300 rail with adequate ventilation; follow rack slotting guidance.
- Wiring practices: Segregate DI wiring from VFD/motor cables; use ferrules and verify 24 VDC polarity.
- Field supply: Provide a clean 24 VDC source for inputs; group commons as per your drawing to avoid nuisance noise.
- Handling & safety: Power down before removal/insertion; ESD protection during handling.
- Routine care: Periodic dust removal, terminal torque checks, and proof tests of critical interlocks.
Quality & Certifications
- Certifications: CE; UL/cUL for control panels (typical for SIMATIC S7‑300 modules); RoHS by series.
- Manufacturer quality: Produced under ISO 9001 quality systems.
- Warranty: 365‑day warranty from shipment date.
If you can share your rack layout, power supply model, and how many DI channels are in use per group, we’ll double‑check the 6ES7321-1BH02-0AA0 fit and prepare a quick functional test record before dispatch.
Reviews
There are no reviews yet.