BEHA UNITEST 93560, Instruction Manual

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5. 2 General Information regarding Measurements
For any test (measurement) the safety references have to be fulfilled.
• In systems with discharge lamps (luminescent lamps) the lamps have to be aged
or operated for minimum 100h, for glow lamps minimum 10 h.
• In systems with vapour discharge lamp (sodium, mercury, halide lamps, etc), the
measurement values may importantly vary due to the different lamp types at dif-
ferent colour spectra.
• Prior to starting the measurements switch on the lamps until stationary condition
of the lighting system is reached (approx. 10 to 15 min.).
• For all measurements, the influence of an external light source on the measure-
ment result must be taken into consideration. In order to obtain maximum preci-
sion two measurement procedures are available:
a) The room in which the measurement has to be carried out has to be complete ob-
scured (e.g. carry out the measurement during the evening or the night).
b) If the room cannot be obscured proceed with a difference measurement. I.e. the
first measurement is carried out with lighting and foreign lighting being switched
on. The second measurement is carried out with all lighting being switched of, at
the same measurement spot. The correct measurement result is deducted from
the difference of both measurements.
Example:
Measurement value 1 1235 lx with lighting or foreign light
Measurement value 2 355 lx without lighting, only foreign light
Measurement result: 1235 lx – 355 lx = 880 lx
For this type of measurement please make sure that both measurements are car-
ried out immediately one after the other as the share of daylight or foreign light may
fluctuate considerably.
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