6ES7331-7KF02-0AB0 SM 331 8-Channel Analog Input Module | Siemens

The Original New Siemens 6ES7331-7KF02-0AB0 SIMATIC S7-300 SM 331 Analog Input Module is an isolated, universal analog input module for the S7-300 automation system. It provides 8 configurable channels for voltage, current, thermocouple, resistance, and RTD signals with selectable 9/12/14-bit resolution. Featuring module-level diagnostics, alarm functions, and support for active backplane bus hot-swapping, this module delivers versatile, high‑precision signal acquisition for demanding industrial process and machine automation applications.

Core Engineering Highlights:
8 configurable analog inputs (voltage/current/TC/resistance/RTD) | Selectable 9/12/14-bit resolution | 24V DC supply | Optical isolation | Module diagnostics and alarm functions | 1x 20‑pole removable/insertable with active backplane bus | IP20 protection | 40 x 125 x 117 mm | Approx. 250‑291 g | 0°C to +60°C operating

Key Features:

• Original New Siemens 6ES7331-7KF02-0AB0 module

• 8 analog input channels — configurable for voltage, current, thermocouple, resistance, or RTD signals

• Selectable resolution: 9, 12, or 14 bits for flexible accuracy and conversion speed

• Optical isolation between input channels and backplane bus for enhanced noise immunity

• Integrated module diagnostics and alarm functions

• Supports 2‑wire and 4‑wire transmitters with mechanical range selector module (position C for 4‑wire, D for 2‑wire)

• 1x 20‑pole removable/insertable connector with active backplane bus support

• 24V DC reverse polarity protection

• 1W typical power loss

• DIN rail mounting for S7‑300 rail

• IP20 protection for control cabinet installation

• Wide operating temperature: 0°C to +60°C

Applications:

• Analog signal acquisition from pressure, flow, level, and temperature transmitters

• Thermocouple and RTD temperature measurement (PT100, Ni100)

• Voltage and current signal monitoring in machine and process automation

• Distributed I/O expansion for S7‑300 systems

• Legacy S7‑300 system maintenance and spare part replacement

• Multi‑sensor applications requiring universal input capability

Technical Specifications:

• Catalog Number: 6ES7331-7KF02-0AB0

• Product Type Designation: SM 331, AI 8x12/14 bit

• Product Family: SIMATIC S7-300

• Product Status: Spare part

• Number of Analog Inputs: 8 (4 for resistance measurement)

Supply Voltage & Current:

Analog Inputs:

Supported Input Ranges:

Supported Sensors:

Accuracy & Error Limits:

Protection & Isolation:

Physical & Environmental:

Compatibility Information:

• Compatible with: Siemens SIMATIC S7‑300 CPUs (all variants)

• Mounting: S7‑300 DIN rail

• Configuration: Requires STEP 7 or TIA Portal (with HSP) for parameter setting

• Wiring: Mechanical range selector module on the physical module must be set correctly: position "D" for 2‑wire current transmitters, position "C" for 4‑wire connections

• Front Connector: Requires 20‑pin screw terminal front connector (6ES7392-1AJ00-0AA0, sold separately)

• Active Backplane Bus: Supports hot‑swapping with active backplane bus (requires compatible rack)

Typical System Architecture:
24V DC Power Supply
↓
S7‑300 CPU (e.g., CPU 315-2 PN/DP)
↓
6ES7331-7KF02-0AB0 SM 331 Analog Input Module (8 channels, 40 mm width)
│
├── Channel 1-8 → Voltage / Current / Thermocouple / RTD / Resistance Sensors
├── Configurable Resolution → 9/12/14 bits (per channel group)
├── Isolation → Galvanic isolation between inputs and backplane bus
├── Diagnostics → Module-level diagnostic alarms
├── Active Backplane Bus → Hot‑swappable module replacement
│
↓
Front Connector (20‑pin) → Field Devices (Transmitters, Sensors, Thermocouples)

Related Products:

• 6ES7392-1AJ00-0AA0 – 20‑pin screw terminal front connector for S7‑300 (required accessory)

• 6ES7331-1KF02-0AB0 – SM 331 AI 8x13 bits (simplified measurement functions)

• 6ES7331-7HF01-0AB0 – SM 331 AI 8x13 bits isolated (faster conversion, higher accuracy)

• 6ES7332-5HD01-0AB0 – SM 332 AO 4x12 bits (isolated analog output)

• 6ES7315-2EH14-0AB0 – CPU 315-2 PN/DP (compatible CPU)

• 6ES7390-1AE80-0AA0 – S7‑300 mounting rail (160mm)

• 6ES7390-1AF30-0AA0 – S7‑300 mounting rail (530mm)

PLC ERA is an independent industrial automation distributor supplying 100% genuine Original New products through established global supply channels. Siemens, SIMATIC, S7-300, and TIA Portal are trademarks of Siemens AG.