The intruction manual tells you info about sensitive range, photodiode, intensity, and calibration. There are lots of things such as serial box interface, instruments, and interface are described inside the intruction manual.
In the intruction manual the reader can find explanation regarding range, sensor, light intensity, and response. Here are selected from the intruction manual:
The sensor uses a Hamamatsu S1133 silicon photodiode. It produces a voltage which is proportional to light intensity. The spectral response approximates the response of the human eye as shown in this diagram. The switch on the box is used to select the range. If the reading from the sensor Spectral Response of the reaches the maximum for the selected ranges, you Hamamatsu S1133 Photodiode need to switch to a less sensitive range. If the reading is very small or 0, you need to select a more sensitive range
Additionally, this intruction manual tells you information about light meter, light sensor, and the light sensor.