2.2.3 Perform Optical Calibration
After the first installation, it is required to perform optical system calibration for the
module to ensure the accuracy of rain detection. Calibration steps:
1. Ensure the external surface of the glass is clean, dry and free from foreign matters, and
it is recommended to calibrate in a dark room to keep the calibration free from
interference of light.
2. According to the commands listed in Table 1.9, the host sends to the module an
automatic calibration command: "3A 83 00 00 54". After the module receives it, it will
automatically perform optical system calibration and send the calibration result to the
host. The result will be written into Flash so there is no need to calibrate again after
power on. If the host receives the command "3A 82 04 00 91" for unsatisfactory optical
system calibration, it means that the optical path asymmetry of the optical system is
beyond the adjustable range due to the mechanical structure and installation accuracy,
which reduces the module
’
s ability to resist sunlight interference, thus leading to
misjudgment.
During use, if the optical system changes, perform the optical system calibration again as
per needs.
2.2.4 Initialize Module to Read Rainfall Status & Control Wiper
After the first calibration, the module can be used without initialization if there is no
special requirements. The host can control the wiper according to the rainfall status
automatically reported by the module. If you have special needs, you can adjust the
rainfall status output frequency according to Table 1.10, adjust the rain detection
sensitivity according to Table 1.11, etc. The adjustable parameters such as calibration
value, V, S, N and frequency are saved when powered off, so there is no need to
reconfigure them every time you power on.
