Temperature Sensor Interface Module for Programmable Logic Controllers (PLC)


Design files


The TIDA-00018 reference design enables faster development of high precision temperature measurement solutions using 24-Bit delta-sigma ADC and most widely used temperature sensors like thermocouple and RTD. The design guide will address the sensor signal conditioning, thermocouple cold junction compensation, ratiometric measurement technique for RTD, recommended software flow, sensor linearization, sensor diagnostics, transient protection, PCB layout and other practical design considerations for achieving high precision robust design for temperature measurement in industrial applications.  The Temperature Sensor Interface Module is a fully isolated design, which is essential for small sensor signal measurement. The heart of this reference design is a 24-Bit delta-sigma ADC that provides a high resolution, high integration, low noise, and low cost complete sensor analog front-end (AFE) for DC sensing applications. This ADC also makes it suitable to interface with different types of sensors, thus saving board space, reducing design efforts, decreasing the time to market, and lower BOM cost. Furthermore, external protection circuitry has been successfully tested for compliance with regulatory IEC61000-4 EFT, ESD, and surge standards. Compliance to IEC61000-4 is necessary to ensure that the design not only survives but also perform as intended in the harsh/noisy industrial environment.

  • Two different sensor input channels:
    • K-Type thermocouple input with CJC
    • Compatible to 2-, 3- or 4-wire RTD probes
  • Ratiometric measurement for RTD
  • Overall measurement accuracy better than:
    • For thermocouple: ±1°C
    • For RTD: ±0.4°C
  • Sensor wire open circuit or signal out-of-range detection
  • Comply to IEC-61000-4 requirements:
    • IEC-61000-4-4: EFT up to ±1KV @ 5KHz on signal ports
    • IEC-61000-4-2: ESD up to 4KV contact & 8KV air discharge
    • IEC-61000-4-5: Surge up to ±1KV line-earth (CM) on signal ports
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A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDU271.PDF (3225 K)

Reference design overview and verified performance test data

TIDR620.PDF (408 K)

Detailed schematic diagram for design layout and components

TIDR621.PDF (202 K)

Complete listing of design components, reference designators, and manufacturers/part numbers

TIDC424.ZIP (3888 K)

Files used for 3D models or 2D drawings of IC components

TIDC425.ZIP (319 K)

Design file that contains information on physical board layer of design PCB

TIDR622.PDF (645 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

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Technical documentation

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Type Title Date
* Design guide Temperature Sensor Interface Module for PLCs Design Guide Mar. 26, 2014
Technical article Delta-sigma ADC basics: Walking around the delta-sigma blocks Mar. 03, 2015

Related design resources

Reference designs

TIDA-00119 12-Bit, 8 Channel, Integrated Analog Input module for Programmable Logic Controllers (PLC)

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