Siemens 6ES7331-1KF02-0AB0 SM331 8AI Analog Module

6ES7331-1KF02-0AB0 SIMATIC S7-300 SM 331 Analog Input Module

Product Introduction

The Siemens 6ES7331-1KF02-0AB0 is a high-performance analog input module from the SIMATIC S7-300 family. This SM 331 module features 8 isolated analog inputs with a resolution of 13 bits. It supports a wide variety of signal types, including voltage, current, resistance, and resistance thermometers (RTDs) such as Pt100, Ni100, Ni1000, and LG-Ni1000.

This module is ideal for process automation applications requiring precise measurement of temperature, pressure, flow, or level. It connects via a 40-pin front connector. The 6ES7331-1KF02-0AB0 offers excellent flexibility with multiple input ranges and linearization options.

Technical Specifications

The 6ES7331-1KF02-0AB0 draws a maximum of 90 mA from the 5 V DC backplane bus. Its typical power loss is only 0.4 W, making it very energy-efficient. The module provides 8 analog input channels, each capable of resistance measurement.

Input Ranges and Signal Types

This SM 331 supports a broad range of input signals. For voltage measurement, it accepts various ranges including ±50 mV, ±500 mV, ±1 V, ±5 V, ±10 V, 0 to 10 V, and 1 to 5 V. The input resistance for all voltage ranges is 100 kΩ.

For current measurement, the module supports 0 to 20 mA, 4 to 20 mA, and ±20 mA. The input resistance for current ranges is 100 Ω, which provides a low burden on the signal source.

For resistance thermometers, the 6ES7331-1KF02-0AB0 supports Pt100 (standard and climatic), Ni100 (standard and climatic), Ni1000 (standard and climatic), and LG-Ni1000 (standard and climatic). It also supports direct resistance measurement in ranges of 0 to 600 Ω and 0 to 6000 Ω.

Protection and Destruction Limits

The module includes protection against overvoltage and overcurrent. For voltage inputs, the destruction limit is 30 V for up to 1 second, with a continuous limit of 12 V. For current inputs, the maximum permissible input current is 40 mA, preventing damage to the input circuitry.

Conversion Time and Resolution

The SM 331 delivers a maximum resolution of 13 bits, including the sign bit. The integration time is parameterizable, with options for 50 Hz or 60 Hz interference suppression. The basic conversion time is 66 ms at 50 Hz and 55 ms at 60 Hz, ensuring stable readings even in electrically noisy environments.

Linearity and Temperature Compensation

Characteristic linearization is parameterizable for resistance thermometers, including Pt100, Ni100, Ni1000, and LG-Ni1000 in both standard and climatic versions. However, this module does not support thermocouples (TC), and temperature compensation is not available.

Cable Length and Diagnostics

For shielded analog cables, the maximum length is 200 meters. However, for the sensitive 50 mV range, the length is limited to 50 meters to maintain signal integrity.

Notably, this 6ES7331-1KF02-0AB0 does not include diagnostic functions. There are no alarms for limit value violation, and the group error SF (red) LED is not present. Diagnostic information is not readable.

Potential Separation

The analog inputs are not isolated from each other, but they are isolated from the backplane bus. The isolation is tested with 500 V DC, providing basic protection against ground loops.

Mechanical and Environmental Data

Physically, the module measures 40 mm in width, 125 mm in height, and 117 mm in depth. It weighs approximately 250 g. The module operates reliably within an ambient temperature range of 0 °C to 60 °C.

Installation Guidelines

Installing the 6ES7331-1KF02-0AB0 requires careful attention to wiring. Start by disconnecting the power supply to your S7-300 rack. Mount the module onto the DIN rail and secure it. Connect the 40-pin front connector, ensuring proper shielding for analog signals. For RTD measurements, use three-wire or four-wire connections to compensate for lead resistance. For current measurements, configure the wiring as two-wire (with external supply) or four-wire transducers. Finally, configure the input ranges and linearization in STEP 7 hardware configuration and download the project.

Packaging List

• Siemens 6ES7331-1KF02-0AB0 SM 331 analog input module (1 unit)

• Labeling strips (1 set)

• Manual (1 copy)

Shipping Method: FedEx, UPS, DHL

Frequently Asked Questions (FAQ)

1. Does the 6ES7331-1KF02-0AB0 support thermocouple inputs?
No, this module does not support thermocouples. It is designed for voltage, current, resistance, and RTD signals only.

2. What is the maximum resolution of this SM 331 module?
The maximum resolution is 13 bits, including the sign bit, providing good precision for most industrial measurements.

3. Can I connect a 2-wire transmitter to this Siemens analog input module?
Yes, the 6ES7331-1KF02-0AB0 supports 2-wire transducers with an external power supply.

4. What is the maximum cable length for analog signals?
For shielded cables, the maximum length is 200 meters. For the 50 mV range, it is reduced to 50 meters.

5. Does this module provide diagnostic alarms for wire-break or short-circuit?
No, diagnostic functions are not available on this SM 331. Limit value alarms and diagnostic alarms are not supported.