Description

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.