X9₁-US Photometer
VL-3704-4 Illuminance Detector
LDM-9901-4 Luminance Detector

The US version of the X9₁ (Xnine one) meter plus VL-3704-4 and/or LDM-9901-4 light detector forms a compact lightweight photometer for the measurement of illuminance in foot-candles (fc) and luminance in foot-lamberts (fL). Lux meters and luminance meters are the traditional instruments used in most lighting applications. The X9₁ lightmeter design features separate meter and two cable connected detector heads for illuminance and luminance measurements. The VL-3704-4 Illuminance detector is fitted with a precise photometric correction filter and cosine diffuser. It’s V(λ) spectral sensitivity matches the DIN CIE standard to equal or better than 5% meeting the DIN Class B specification. Its 20 mm low profile height allows measurement close to the reference level. The LDM-9901-4 Luminance detector is designed with a chromatically corrected lens for a measurement distance independent V(λ) match of equal to or better than 5% to the DIN CIE standard. Its field of view is 1° and the measurement distance range 40 cm to infinity. To target the object to be measured, the LDM-9901 has a notch and bead sight which has marks for near and far field distances. The X9₁ meter is a handheld battery operated meter with 9 mm high character LCD display for easy viewing. Its high linear current to voltage amplifier offers seven manually or automatically selected gain ranges. The max. error within this wide dynamic range is 0.2 %. Operating the X9₁ is simple. Once set-up all settings are stored and recalled on next power-up unless settings are changed. The light detector connected is recognized by the meter and set to the associated measurement quantity fc or fL. The meter is operated by a standard 9 V battery. An optional BHO-04 hard-shell case is available.