The V420 from Highland Technology simulates resistors, resistance temperature detectors (RTDs), thermistors, strain gages, and load cells. It remains accurate for dc, ac, or pulsed excitation. Users directly program resistances or simulated RTD temperatures. According to the company, the V420 is quiet and reliable, and resistance changes are fast and monotonic with no contact bounce or transient switching errors. The device simulates eight two- or four-wire resistive sensors. Channels are individually programmable in four ranges from five ohms to 65.5 K ohms and operate from microvolts to 24 v/50 mA. Channels are fully isolated with up to 750-V common-mode range with overvoltage protection up to 50 V. The module provides channel calibration check capability and optional built-in self test.