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


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This reference design provides a complete solution for a single supply industrial control Analog Input Module. The reference design is suitable for process control end equipment like Programmable Logic Controllers (PLC), Distributed Control system (DCS), Data Acquisition Systems (DAS) modules that must digitize standard industrial current inputs and bipolar or unipolar input voltage ranges up to ±10V.

In an industrial environment the analog voltage and current ranges typically include ±2.5 V, ±5 V, ±10 V, 0 V to 5 V, 0 V to 10 V, 4 mA to 20 mA, and 0 mA to 20 mA. This reference design can measure all standard industrial voltage and current inputs. Eight channels are provided on the module and each channel can be configured as a current or voltage input with software configuration. The SAR based architecture of ADS8688 leverages better sampling rate. The ADS8688 also includes an on-chip PGA. The on-chip PGAs are used to provide gain and level shift the bipolar signals. The ISO7141 & ISO1541D provides digital signal isolation between host microcontroller and measurement side. The power isolation has been achieved using LM5017 based Flybuck transformer. The module has on-board EEPROM to store calibration data and module configuration data. This reference design also demonstrate the TI products like hot swap & in-rush current limit controller, isolated Flybuck controller, low noise LDO, and I2C to GPIO expander that can be used in the entire PLC signal processing chain. The module has been designed to be pluggable to the IO Controller (TIDA-00123) for quick testing & evaluation. The module reference design also includes external protection circuit and has been tested and verified to be compliant with IEC61000-4 standards – EFT, ESD and Surge requirements with IO Controller platform.

  • 8 channel, 16 bit SAR ADC ADS8688 that supports from 300ksps to 30ksps per channel
  • Programmable channels: Each channel can be configured as current or voltage input with software configuration
  • Programmable Current Range (0-20mA) and Voltage range (+/-10V)
  • Single 24V input power supply operation
  • Designed for IEC-61000 compliance (IEC-61000-4-4: EFT up to ±2KV @ 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)


TI Devices (8)

Order samples, get tools and find more information on the TI products in this reference design.

Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
ADS8688  16-Bit, 500-kSPS, 8-Channel, Single-Supply, SAR ADCs with Bipolar Input Ranges  Analog to Digital Converter  Sample & Buy View Design Kits & Evaluation Modules
ISO1540  2.5 kVrms Isolated Bidirectional Clock, Bidirectional I2C Isolators  Isolation  Sample & Buy View Design Kits & Evaluation Modules
ISO7141CC  4242-VPK Small-Footprint and Low-Power 3/1 Quad Channel Digital Isolator with Noise Filter  Isolation  Sample & Buy View Design Kits & Evaluation Modules
LM5017  7.5-100V Wide Vin, 600mA Constant On-Time Synchronous Buck Regulator  Step-Down (Buck)  Sample & Buy View Design Kits & Evaluation Modules
LM5069  Positive High Voltage Hot Swap / Inrush Current Controller with Power Limiting  Protection, Monitoring and Hot Swap  Sample & Buy View Design Kits & Evaluation Modules
LM94022  ±1.5°C Temperature Sensor with Multiple Gain and Class-AB Analog Output  Temperature Sensors  Sample & Buy View Design Kits & Evaluation Modules
TCA6408A  Low-Voltage 8-Bit I2C and SMBus I/O Expander  I2C  Sample & Buy View Design Kits & Evaluation Modules
TPS709  150-mA, 30-V, Ultra-Low IQ, Wide Input Low-Dropout Regulator with Reverse Current Protection  Linear Regulator (LDO)  Sample & Buy View Design Kits & Evaluation Modules

Technical Documents
User guides (1)
Title Abstract Type Size (KB) Date Views TI Recommends
PDF 7745 17 Sep 2014 1,912
Design files (6)
Title Abstract Type Size (KB) Date Views
ZIP 3052 30 Jul 2014 167
ZIP 4087 30 Jul 2014 95
PDF 3442 30 Jul 2014 152
PDF 409 30 Jul 2014 113
PDF 40 30 Jul 2014 183
PDF 1082 30 Jul 2014 1,172
Related Tools & Software

Reference Designs (3)

Design Kits & Evaluation Modules (1)

Name Part Number Tool Type
BeagleBone Black Development Board  BEAGLEBK  Evaluation Modules & Boards 

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