BEHA UNITEST 93408 - 6 Calculation Example; Using the Analogue Recorder Output (Only 93408)

5.1 Using the analogue recorder output (93408)
Model 93408 is equipped with an analogue recorder output. A data recorder may be connec-
ted to this output via a connecting cable of a maximum length of 3 m.
The connection to the luxmeter is carried out via a conventional 3.5 mm jack bush.
The connecting impedance must not fall below 10 kΩ for model 93408.
If the connections are short-circuited, the display no longer indicates any usable measurement
results.
The output voltage amounts to 2 V, for model 93408, respectively referring to the full reading
of the measurement range.
6.0 Calculation example:
Watt rule:
An illumination of 100 lx in a room requires:
• via light bulb illumination (15 lm/W), a power of approx. 20 W/m
2
• via tubular fluorescent lamp (60 lm/W), a power of approx. 5.5 W/m
2
.
You want to calculate the number of tubular fluorescent lamps as well as the wattage neces-
sary for an office which according to the table of standard values requires an illumination of
500 lx. The total office surface is 40 m
2
.
100 lx requires a wattage of:
W
P = 5,5 ------- x 40 m
2
= 220 W
m
2
for 500 lx factor five, i.e. approx. 1100 W.
Tubular fluorescent lamps of the type 65 W are to be installed.
1100 W
Number of lamps = ------------ = 16.9
65 W
20
Using the analogue recorder output (93408)