Available. The Keyence FS-V21R is a fiber amplifier main unit designed for NPN output, featuring a red LED light source. It offers multiple response times, including 250 µs (FINE), 500 µs (TURBO), 1 ms (SUPER TURBO), 4 ms (ULTRA TURBO), 500 µs (HIGH RESOLUTION), and 50 µs (HIGH SPEED). The device supports light-ON/Dark-ON output selection and provides dual digital monitors with 7-segment displays for preset and current values. Additional features include a shift function with a maximum of ±1,999, and a timer function with selectable modes and variable ranges from 1 to 500 ms. The control output is an NPN open collector with a maximum of 100 mA (40 VDC max) and a residual voltage of 1 V max. The operating voltage ranges from 12 to 24 VDC ±10%, with a ripple of 10% or less. The device has a power consumption of up to 650 mW (27 mA max at 24 VDC) when S-APC is off, and up to 720 mW (30 mA max at 24 VDC) when S-APC is on. Environmental resistance includes ambient light tolerance up to 20,000 lux for incandescent lamps and 30,000 lux for sunlight, with an operating temperature range of -10 to +55 °C (14 to 131 °F) and a humidity range of 35 to 85% RH (no condensation). The device is housed in a polycarbonate case and weighs approximately 80 g (including a 2-meter cable).