Programmable Logic Controller Guide: Selection, Application, and Maintenance for Engineers
PLC selection guide for engineers covering IEC 61131 compliance, Siemens, Rockwell, Schneider, ABB comparison, scan time sizing, and wiring. Shop at Stoklink.
The Siemens 6ES7231-5PB50-0XB0 is a SIMATIC S7-1200 SB 1231 RTD signal board with 2 analog inputs for Pt100, Pt1000, Ni100, Ni1000, and other resistance-thermometer types, offering 15-bit plus sign resolution and +/-0.1% accuracy at 25 C. It supports cable runs up to 100 m shielded, provides 707 V DC isolation, carries an IP20 rating, and weighs only 29 g, mounting directly on the CPU's signal-board slot.
The board reads 15 resistance-transmitter types (Pt, Ni, Cu, and raw resistance ranges) under a single ordering number, so the same board covers Pt100 and Pt1000 sensors without a separate SKU per sensor type - the type is selected in the hardware configuration, not at purchase. At 15 x 62 x 63 mm it mounts directly on the CPU's signal-board slot, adding RTD inputs without consuming a base-unit expansion slot or DIN-rail space. +/-0.1% accuracy at 25 C fits process-temperature monitoring rather than laboratory-grade calibration work.
Used for direct RTD temperature sensing - motor winding temperature, bearing temperature, process fluid temperature - on compact S7-1200 CPUs where a full I/O module isn't justified for two channels.
| Product type designation | SB 1231, AI 2x 16-bit RTD |
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| from backplane bus 5 V DC, typ. | 20 mA |
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| Power loss, typ. | 0.1 W |
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| Part number | 6ES7231-5PB50-0XB0 |
|---|---|
| Type designation | SB 1231, AI 2x 16-bit RTD |
| Brand | Siemens |
| Condition | New, factory sealed |
| Source | Siemens and its authorised distributors |
| Warranty | Manufacturer warranty |
| Lifecycle status | Active, in production |
| EAN | 4034106036348 |
| ETIM class | EC001420 |
| eCl@ss | 27242201 |
| Number of analog inputs | 2; Resistance thermometer |
|---|---|
| permissible input voltage for voltage input (destruction limit), max. | ±35 V |
| Technical unit for temperature measurement adjustable | Degrees Celsius/degrees Fahrenheit |
| Input ranges: Voltage | No |
| Input ranges: Current | No |
| Input ranges: Thermocouple | No |
| Input ranges: Resistance thermometer | Yes; Resistance-type transmitter: Pt10, Pt50, Pt100, Pt200, Pt500, Pt1000, Ni100, Ni120, Ni200, Ni500, Ni1000, Cu10, Cu50, Cu100, LG-Ni1000 |
| Input ranges: Resistance | Yes; 150 Ω, 300 Ω, 600 Ω |
| Input ranges (rated values), resistance thermometer: Cu 10 | Yes |
| Input ranges (rated values), resistance thermometer: Input resistance (Cu 10) | 10 Ω |
| Input ranges (rated values), resistance thermometer: Ni 100 | Yes |
| Input ranges (rated values), resistance thermometer: Ni 1000 | Yes |
| Input ranges (rated values), resistance thermometer: LG-Ni 1000 | Yes |
| Input ranges (rated values), resistance thermometer: Ni 120 | Yes |
| Input ranges (rated values), resistance thermometer: Ni 200 | Yes |
| Input ranges (rated values), resistance thermometer: Ni 500 | Yes |
| Input ranges (rated values), resistance thermometer: Pt 100 | Yes |
| Input ranges (rated values), resistance thermometer: Pt 1000 | Yes |
| Input ranges (rated values), resistance thermometer: Pt 200 | Yes |
| Input ranges (rated values), resistance thermometer: Pt 500 | Yes |
| Input ranges (rated values), resistors: 0 to 150 ohms | Yes |
| Input ranges (rated values), resistors: 0 to 300 ohms | Yes |
| Input ranges (rated values), resistors: 0 to 600 ohms | Yes |
| Cable length: shielded, max. | 100 m; to the sensor |
| Measurement principle | integrating |
|---|---|
| Integration and conversion time/resolution per channel: Resolution with overrange (bit including sign), max. | 15 bit; + sign |
| Integration and conversion time/resolution per channel: Integration time, parameterizable | Yes |
| Integration and conversion time/resolution per channel: Interference voltage suppression for interference frequency f1 in Hz | 85 dB at 10 / 50 / 60 / 400 Hz |
| Smoothing of measured values: parameterizable | Yes |
| Smoothing of measured values: Step: None | Yes |
| Smoothing of measured values: Step: low | Yes |
| Smoothing of measured values: Step: Medium | Yes |
| Smoothing of measured values: Step: High | Yes |
| Temperature error (relative to input range), (+/-) | 25 °C ±0.1 % / -20 °C to 60 °C ±0.2 % of the full-scale deflection |
|---|---|
| Repeat accuracy in steady state at 25 °C (relative to input range), (+/-) | 0.05 % |
| Interference voltage suppression for f = n x (f1 +/- 1 %), f1 = interference frequency: Common mode interference, min. | 120 dB |
| Alarms | Yes |
|---|---|
| Diagnostics function | Yes; Can be read out |
| Alarms: Diagnostic alarm | Yes |
| Diagnoses: Wire break | Yes |
| Diagnostics indication LED: DIAG LED | Yes |
| Diagnostics indication LED: for status of the inputs | Yes |
| Isolation tested with tested with | 707 V DC (type test) |
|---|---|
| Between channels | 120 V AC |
| IP degree of protection | IP20 |
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| CE mark | Yes |
|---|---|
| CSA approval | No |
| UL approval | Yes |
| cULus | Yes |
| FM approval | No |
| RCM (formerly C-TICK) | Yes |
| KC approval | Yes |
| Marine approval | No |
| Free fall: Fall height, max. | 0.3 m; five times, in product package |
|---|---|
| Ambient temperature during operation: horizontal installation, min. | -20 °C |
| Ambient temperature during operation: vertical installation, min. | -20 °C |
| Ambient temperature during storage/transportation: min. | -40 °C |
| Ambient temperature during storage/transportation: max. | 70 °C |
| Air pressure acc. to IEC 60068-2-13: Operation, min. | 540 hPa |
| Air pressure acc. to IEC 60068-2-13: Operation, max. | 1 140 hPa |
| Air pressure acc. to IEC 60068-2-13: Storage/transport, min. | 540 hPa |
| Air pressure acc. to IEC 60068-2-13: Storage/transport, max. | 1 140 hPa |
| Altitude during operation relating to sea level: Installation altitude, min. | -1 000 m |
| Relative humidity: Operation, max. | 95 %; no condensation |
| Vibrations: Vibration resistance during operation acc. to IEC 60068-2-6 | 3.5 mm from 5 - 8.4 Hz, 1g from 8.4 - 150 Hz |
| Vibrations: Operation, tested according to IEC 60068-2-6 | Yes |
| Shock testing: tested according to IEC 60068-2-27 | Yes; IEC 68, Part 2-27; half-sine, 15 g, 11 ms |
| Pollutant concentrations: SO2 at RH < 60% without condensation | S02: < 0.5 ppm; H2S: < 0.1 ppm; RH < 60 % condensation-free |
| required front connector | Yes |
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| Enclosure material (front): Plastic | Yes |
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| Width | 15 mm |
|---|---|
| Height | 62 mm |
| Depth | 63 mm |
| Weight, approx. | 29 g |
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| Manufacturer Declara- Miscellaneous China RoHS tion | For use in hazard- |
|---|---|
| General Product Approval EMV Maritime application Manufacturer Declara-tion | ous locations |
| Net weight | 0.043 kg |
|---|---|
| Package dimensions | 82 × 34 × 79 mm |
| Country of origin | DE |
| Shipping weight | 0.543 kg |
| Ships from | Türkiye |
| Dispatch | 12 Nov |
| Stock | In stock |
Source: manufacturer data · Last verified: 01 Nov 2026
No documents are on file for this part yet.
Ask us for the datasheetThe tariff (HS) code on file for SB 1231, AI 2x 16-bit RTD is 85389091.
The EAN (GTIN) of SB 1231, AI 2x 16-bit RTD is 4034106036348.
SB 1231, AI 2x 16-bit RTD ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival. Stock items are dispatched within 1–2 business days.
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