Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | Siemens 6ES7231-5QD30-0XB0 |
| Manufacturer | Siemens AG |
| Product Type | Analog Input Module (SM 1231) |
| Series | SIMATIC S7-1200 |
| Description | SM 1231 AI 4 x 16-bit TC |
| Number of Inputs | 4 (thermocouple or voltage) |
| Resolution | 15 bits + sign (voltage), 0.1°C (temperature) |
| Voltage Input Range | ±10 V, ±5 V, ±2.5 V (configurable) |
| Maximum Overvoltage Protection | ±35 V |
| Input Impedance | ≥ 10 MΩ (voltage) |
| Noise Suppression | 85 dB for selected filter (10/50/60/400 Hz) |
| Common Mode Rejection | >120 dB at 120V AC |
| Isolation (Field to Logic) | 500V AC / 707V DC (type test) |
| Channel-to-Channel Isolation | 120V AC |
| Cold Junction Compensation Error | ±1.5°C |
| Power Dissipation | 1.5 W |
| Current Consumption (SM Bus) | 80 mA |
| Current Consumption (24V DC) | 40 mA |
| Dimensions (W×H×D) | 45 × 100 × 75 mm |
| Weight | Approx. 180 g |
| Operating Temperature | -20°C to 60°C |
| Storage Temperature | -40°C to 70°C |
| Degree of Protection | IP20 |
| Approvals | CE, CSA, cULus, UL |
Main Features and Advantages
Superior temperature measurement precision: The Siemens 6ES7231-5QD30-0XB0 delivers exceptional accuracy for thermocouple temperature measurement, with a resolution of 0.1°C and repeatability of ±0.05% full scale. The module reports temperature values in degrees multiplied by ten (e.g., 25.3°C is reported as decimal 253), simplifying the scaling process in the PLC program . This high resolution makes the Siemens 6ES7231-5QD30-0XB0 suitable for applications requiring precise temperature control and monitoring.
Built-in cold junction compensation: The Siemens 6ES7231-5QD30-0XB0 features integrated cold junction compensation with an error margin of ±1.5°C, eliminating the need for external reference junction devices. This simplifies installation and reduces component costs while ensuring accurate readings across varying ambient temperatures . The Siemens 6ES7231-5QD30-0XB0 also provides diagnostic capabilities including over-range, under-range, over-flow, under-flow, and open-wire detection alerts, helping maintenance teams quickly identify and resolve sensor wiring issues without specialized test equipment.
Flexible configuration and robust protection: The Siemens 6ES7231-5QD30-0XB0 supports multiple thermocouple types and voltage ranges, configurable through the TIA Portal software. The module’s comprehensive isolation (500V AC field-to-logic, 707V DC type tested, and 120V AC channel-to-channel) protects the S7-1200 CPU from field-side surges and noise, ensuring long-term reliability . The Siemens 6ES7231-5QD30-0XB0 also includes configurable noise suppression filters (10 Hz, 50 Hz, 60 Hz, or 400 Hz) that provide 85 dB rejection of power line frequency noise, making the module highly immune to electrical interference commonly found in industrial settings . The ±35V overvoltage protection on each input further safeguards the Siemens 6ES7231-5QD30-0XB0 against accidental wiring errors or transient voltage spikes, extending module life and reducing maintenance costs.
Application Field
The Siemens 6ES7231-5QD30-0XB0 is primarily deployed in industrial applications requiring high-accuracy temperature measurement. In the manufacturing and process industries, this module is widely used with thermocouple sensors to monitor critical process temperatures in furnaces, ovens, kilns, and reactors. The Siemens 6ES7231-5QD30-0XB0 provides the precision needed for quality control in industries such as heat treatment, ceramics, glass manufacturing, and metal processing, where temperature regulation directly impacts product quality and energy efficiency .
The power generation and energy sectors rely on the Siemens 6ES7231-5QD30-0XB0 for monitoring thermal process parameters in boilers, turbines, and heat exchangers. In combined heat and power (CHP) plants, the Siemens 6ES7231-5QD30-0XB0 provides reliable temperature data used by control algorithms to optimize combustion efficiency and reduce emissions. Its high common-mode rejection (>120 dB) makes the Siemens 6ES7231-5QD30-0XB0 ideal for environments with significant electrical noise, such as turbine halls and generator rooms .
The Siemens 6ES7231-5QD30-0XB0 also finds application in the food and beverage industry, pharmaceutical manufacturing, and HVAC systems. In these sectors, the module monitors temperatures in fermentation vessels, sterilization equipment, cleanrooms, and environmental chambers. The Siemens 6ES7231-5QD30-0XB0‘s 0.1°C resolution enables precise climate and process control essential for regulatory compliance and product consistency. The flexible noise suppression options allow the Siemens 6ES7231-5QD30-0XB0 to adapt to varying power line conditions globally, while the IP20 protection class and wide operating temperature range (-20°C to 60°C) make the module suitable for installation in standard industrial control cabinets.
