This reference design showcases space- and cost-optimized architecture for a 4-channel DC-input binary module with improved measurement accuracy and status indication using only two products simplifying system design. MCU-based binary module improves measurement resolution of binary input resulting in improved system performance for accurate and repeatable fault indications and eliminates the need for multiple hardware versions (use same design for multiple nominal voltage inputs). This reduces design, testing, manufacturing and field support efforts. In this design, 4-input channels are configured as group isolated inputs to minimize cost per channel. A 10-bit analog-to-digital converter (ADC) measures the DC inputs within ±3% ±1-V accuracy over wide range. Pre-compliance tests for EMI and EMC have been performed.
- Binary input module design based on reinforced isolation ISOW7841 or ISOW7841F, digital isolator with integrated high-efficiency, power converter with soft-start and 75-mA current output (quad with various configurations for GPIO, SPI or UART interface) simplifying system design
- MSP430G2332 or MSP430FR2111, MCU-based 4-channel DC-input or 2-channel AC or DC voltage input measurement type binary input module
- ISOW7841 provides 46% efficiency with output ripple of 100 mV for 70-mA load (pkpk)
- Accuracy <= ±3% of measured value ±1 V (programming resolution or step size)
- Meets pre-compliance tests for EMI and EMC as per IEC61000-4 and CISPR22 standards