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Selecting a Measurement Range
The meter has three measurement ranges for each unit of measure (0-200, 0-2000, and 0-5000 Fc)
and (0-2000, 0-20000, and 0-50000) Lux). The proper range selection will produce the most accurate
reading. Always select the range that produces the maximum number of digits without exceeding the
maximum count for that particular range. For example, a reading of 1456 Fc should be read on the 0
- 2000 range, not the 0-5000 range.
Zero procedure
The meter zero (display with no light input) may change with time. Occasional checking and
adjustment may be required.
1.
Completely cover the sensor to block out any light.
2.
Set the range switch to the lowest Lux or Fc range.
3.
Using a small screwdriver, adjust the Zero control for a zero display. The last digit may
change slightly. This is normal and does not affect the accuracy of the meter.
Analog Output
The analog output jacks on the front panel produce a 0.1mV DC per digit signal that can be used for
recording or datalogging purposes.
Lighting Type Correction Factors
The 401025 light meter is calibrated under a precise Standard tungsten light source of 2856
O
K. If the
meter is to be used under a different type of light the correction factor of from the table below should
be applied to the readings obtained.
Mercury Lamp
x1.14
Fluorescent Lamp
X0.92 to 1.12
Daylight
x1.00
Sodium
x1.22
Metal Halide
x1.00
