Siemens SM 431 6ES7431-1KF20-0AB0 | S7-400 AI Module

SM 431 · 8 AI · 6ES7431-1KF20-0AB0

Isolated analog input module for S7‑400. Provides 8 channels for voltage, current, or resistance. 14‑bit resolution with overrange. 0.416 ms cycle time. Supports 2‑wire, 3‑wire, and 4‑wire transmitters. No diagnostics function, but robust and reliable for standard process signals.

Oiltech Controls’s Insight

• Perfect for retrofit or upgrade of existing S7‑400 I/O.
• Module draws max. 1 A from backplane – check your power budget.
• Destruction limits: 18 V (voltage) and 40 mA (current) continuous.
• Basic conversion time 52 µs per channel – total cycle 0.42 s.
• No channel‑to‑channel isolation – plan wiring accordingly.

Technical Data – Compact

• Analog inputs: 8 (voltage/current) · 4 (resistance)
• Rated ranges: ±1 V, ±10 V, 1‑5 V · ±20 mA, 4‑20 mA · 0‑600 Ω
• Resolution: 14 bit with sign · Integration time: adjustable (50/60/400 Hz)
• Input resistance: voltage 100 kΩ / 10 MΩ · current 50 Ω / 50 kΩ
• Error (full temp. range): voltage ±0.9 % · current ±0.8 % · resistance ±1 %
• Temperature error: 0.03 %/K · Isolation: tested 2.120 V DC
• Power loss: typ. 4.9 W · Supply: 24 V DC (for 2‑wire transmitters)
• Cable length: shielded, max. 200 m · Dimensions: 25 x 290 x 210 mm · 500 g

Suitable Devices & Systems

• All S7‑400 CPUs (e.g., 416‑2, 414‑3, 417‑4).
• Used in ET 200M remote I/O stations (with IM 153‑x).
• Connects to 2‑wire, 3‑wire, or 4‑wire transmitters and sensors.
• Works with STEP 7 V5.4+ and TIA Portal (via GSD).

Why Buy From Oiltech Controls?

• Over 15 years supplying industrial automation spares.
• Worldwide shipping with FedEx, UPS, or DHL – 24‑28 h dispatch.
• All items are functionally tested – surplus or refurbished.
• 12‑month warranty and pre‑shipment technical verification.
• Expert help for obsolete and legacy control systems.

FAQ – 5 Professional Answers

• Can I use this module for thermocouples?
  No. It does not support thermocouples or RTDs. For temperature, use 6ES7431‑7KFxx.
• What is the difference between 2‑wire and 4‑wire connection?
  2‑wire uses loop power from L+ (requires 24 V DC). 4‑wire uses external supply – module only measures signal.
• How to reduce 50 Hz noise?
  Set integration time to 50 Hz (parameterizable). This suppresses mains interference effectively.
• Is the module hot‑swappable?
  Yes, in S7‑400 with proper configuration (CiR). But avoid pulling under load if possible.
• Which cable length is recommended?
  Shielded, max. 200 m. For longer runs, use signal conditioners or active isolators.

Shipping & Warranty

• 12‑month warranty against defects.
• Dispatch within 24‑28 hours after order confirmation.
• Carriers: FedEx, UPS, DHL – express worldwide.

Inquiries: info@oiltechcontrols.com · +86 158 8020 0923 (WhatsApp)

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