Electronic Module 6ES7134-4NB51-0AB0 6ES7 134-4NB51-0AB0 6ES7134-4NB51-OABO

Siemens 6ES7134-4NB51-0AB0 | SIMATIC ET 200S 2AI RTD High Feature Module — 15-Bit / ±0.1% / 2/3/4-Wire / Line Compensation

High-Feature RTD Input — 15-Bit Resolution with Built-In Lead Compensation

The 6ES7134-4NB51-0AB0 is the 2AI RTD High Feature analog input module for Siemens SIMATIC ET 200S distributed I/O. Two input channels each accept a Resistance Temperature Detector (RTD) — a Pt100, Pt200, Pt500, Pt1000, Ni100, Ni120, or Cu10 sensor — and return a temperature measurement to the PROFIBUS DP master at 15-bit plus sign resolution. At ±0.1% accuracy, this is one of the most precise temperature input options in the ET 200S analogue module range.

The "High Feature" (HF) designation is a meaningful distinction. Standard-feature RTD modules in the ET 200S family provide lower resolution and less precise measurement. The HF module adds higher resolution (15-bit vs 13-bit on standard modules) and internal line resistance compensation — the feature that most differentiates it in field applications.

Internal line resistance compensation removes the temperature measurement error caused by the resistance of the cable connecting the RTD sensor to the module. In 2-wire RTD installations, the cable resistance adds directly to the sensor resistance and is indistinguishable from temperature — a 20-ohm cable looks like a 20-ohm (approximately 50°C at Pt100) temperature offset. The HF module's internal compensation circuit measures and subtracts this cable resistance error without requiring external correction, making 2-wire installations practical at reasonable accuracy for distances where 2-wire cabling is the economic choice.

3-wire and 4-wire installations eliminate cable resistance error at the sensor using the traditional Kelvin sensing or bridge techniques, but require more conductors per sensor. The module supports all three wiring configurations, giving the system designer flexibility in sensor wiring strategy per sensor position.

Key Specifications

6ES7134-4NB51 vs 6ES7134-4NB01 — RTD vs Thermocouple

Both carry the "NB" prefix and High Feature designation, but measure different sensor types:

These two modules are not interchangeable — both accept the same ET 200S terminal module, but the electronics and measurement technique differ entirely. Confirm the sensor type in the installation before specifying.

FAQ

Q1: What RTD sensor types are compatible with the 6ES7134-4NB51-0AB0?

The module accepts standard industrial platinum and nickel RTD types: Pt100, Pt200, Pt500, Pt1000, Ni100, Ni120, Ni1000, and Cu10 (DIN/IEC standard curves). The sensor type is configured per channel in the ET 200S module parameters during STEP 7 or TIA Portal hardware configuration. Confirm the sensor type installed in the application before configuring.

Q2: What terminal module is required for the 6ES7134-4NB51-0AB0?

The module requires an ET 200S terminal module — either TM-E15S24-AT (screw-type terminal, 6ES7193-4CL20-0AA0) or TM-E15C24-AT (spring-clip terminal, 6ES7193-4CL30-0AA0). The terminal module provides the field wiring terminals and physically connects to the ET 200S rail. Terminal modules must be ordered separately.

Q3: How does internal line resistance compensation work, and when does it matter?

In a 2-wire RTD circuit, the cable connecting the sensor to the module carries the measurement current and also introduces a resistance that adds to the sensor reading as a temperature offset error. Internal compensation applies a correction based on a known reference measurement to subtract this cable resistance from the result. This matters most for long 2-wire cable runs — at Pt100, every 1Ω of cable resistance introduces approximately 2.5°C of measurement error without compensation. The HF module reduces this error without requiring 3-wire or 4-wire wiring.

Q4: The 6ES7134-4NB51-0AB0 is discontinued. Is there a current Siemens replacement?

The ET 200S system has been superseded by the ET 200SP platform. ET 200SP offers equivalent RTD input modules with compatible measurement capability. For existing ET 200S installations, source 6ES7134-4NB51-0AB0 through the ET 200S aftermarket. For new system designs, use the ET 200SP equivalent. Confirm exact replacement type with Siemens Industry Mall.

Q5: The SF LED is illuminated on the 6ES7134-4NB51-0AB0. What does this indicate?

The SF (group fault) LED indicates a module-level fault — typically an out-of-range sensor signal (open circuit, short circuit, or sensor reading beyond the configured range), or a module hardware fault. Read the diagnostic data via STEP 7 or TIA Portal to identify the specific fault code. Open-circuit RTD (sensor wire break) is the most common cause of SF LED activation; it presents as an upscale or downscale reading depending on the break type.