4-20mA T 2 Click Board™

Product Code: MIKROE-5540

How Does The 4-20mA T 2 Click Board™ Work? The 4-20mA T 2 Click Board™ is based on the DAC161S997, a low-power 16-bit ΣΔ digital-to-analog converter (DAC) from Texas Instruments, realized as a ΣΔ modulator. Next to ΣΔ DAC, the DAC161S997 also contains an internal ultra-low power voltage reference and an internal oscillator to reduce power and component count in compact loop-powered applications. This architecture, where DAC's output current represents a multiplied copy of the filtered modulator output, ensures an excellent linearity performance while minimizing the device's power consumption. In addition to an industry-standard 4-20 mA current loop over the LOOP terminal, the DAC161S997 also has the possibility of a simple Highway Addressable Remote Transducer (HART) modulator interfacing through an onboard HART TX terminal. It allows the injection of FSK-modulated digital data into the 4-20mA current loop. The 4-20mA T 2 Click Board™ communicates with MCU using a 4-wire SPI serial interface with a maximum frequency of 10MHz, for data transfer and configuration of the DAC functions.

The DAC161S997 supports both Mode 0 and Mode 3 of the SPI protocol. 4-20mA T 2 Click comes with an additional feature, as an interrupt, available on the ERR pin of the mikroBUS™ socket, the loop-error detection/reporting feature. By default, the DAC161S997 detects and reports several types of errors: loop error, SPI timeout error (channel error), frame error, and alarm current. In the case of a fault condition or during the initial Power-Up sequence, the DAC161S997 will output current in either the upper or lower error current band. The band's choice is user-selectable via the appropriate position of an onboard jumper ERRL SEL, while the current error value is programmable through the SPI interface. The 4-20mA T 2 Click Board™ can only operate with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development. SPECIFICATIONS Type Current Applications It can be used for 2-wire 4-20mA current loop transmitters, industrial process control, low-power transmitters, and more On-board modules DAC161S997 - 16-bit DAC for 4-20mA loops from Texas Instruments Key Features High resolution, industry-standard current loop, SPI-programmable, low power consumption, Power-Up programmable output current, loop-error detection and reporting, HART modulator interfacing, and more Interface SPI Compatibility mikroBUS Click board size M (42.9 x 25.4 mm) Input Voltage 3.3V PINOUT DIAGRAM This table shows how the pinout of the 4-20mA T 2 Click Board™ corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns). Notes Pin Pin Notes NC 1 AN PWM 16 NC NC 2 RST INT 15 ERR Loop-Error Interrupt SPI Chip Select CS 3 CS RX 14 NC SPI Clock SCK 4 SCK TX 13 NC SPI Data OUT SDO 5 MISO SCL 12 NC SPI Data IN SDI 6 MOSI SDA 11 NC Power Supply 3.3V 7 3.3V 5V 10 NC Ground GND 8 GND GND 9 GND Ground ONBOARD SETTINGS AND INDICATORS Label Name Default Description LD1 PWR - Power LED Indicator JP1 ERRL SEL Left Power-Up Output Current Level Selection GND/VCC: Left position GND, Right position VCC 4-20MA T 2 CLICK ELECTRICAL SPECIFICATIONS Description Min Typ Max Unit