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A logger also has a fixed number of analog input ranges - you see often 20
mV, 100 mV, 1 V, 5 V and 10 Volt ranges
Lets take for example we use a logger with 12 bits resolution and 5 Volt
input range.
This means that the 5 Volt is divided in 2¹² steps. This is 5/4096 = 0.00122
Volt per step
So the smallest detectable change on the input is 1.22 mV
If we connect an SP Lite with a sensitivity of 75 μVolt/W/m²
One Watt (change) will give 0.075 mV (change) on the output.
So we need a change of 1.22 / 0.075 = 16.2 Watt/m² before we see a change
in the Logger output.
As you can understand this is not acceptable
A minimun of 1 W/m² should be detected (preferably a factor 10 times better)
This can be achieved in lowering the input range to 100 mV (50 times better)
Or selecting a higher resolution e.g. 16 bits (in stead of 12 bits) this is 16
times better. ( 2¹⁶- 2¹² = 2⁴ = 16 )
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