The HVDI32MI-A board provides 32 isolated digital input channels. Each channel is galvanically isolated from all other channels and from the host control bus for voltages up to 1000VRMS. Change-of-State Interrupts allow for an interrupt to the host to be generated from any level change on any input. Built-in-self-test, selectable debounce times, input pulse counter, and input voltages up to 100 Volts makes for a versatile digital interface board.
Each channel contains two voltage comparators and a precision voltage reference, which together with resistor dividers provide precision High and Low detection thresholds from 0.1V up to 60V in increments of approximately 0.02V. Two signals are derived from each channel, corresponding to “Input below Low threshold” and “Input above High threshold”. These signals are converted by the local controller into a digital state that can be read by the host. For system fault detection, or Built-in Selftest (BIST), the local controller also provides an alarm status bit for each channel if the corresponding input is between the two thresholds.