Wireless Data Acquisition System Instruction Manual
25
(1-2) Distance Between Devices
Place the WDT within a 20 m radius (recommended line-of-site distance) of the WDR.
If more distance is required, add another WDT.
(1-3) Ensuring Line of Sight
Good line of sight for each device (WDR, WDT) and free of any obstacles hereafter referred to as the Fresnel Zone - is
required. The Fresnel zone is a three-dimensional space, whose size is estimated as follows:
Line of sight L: 20 m
⇒
Fresnel zone diameter D: about 1.6 m
Line of sight L: 10 m
⇒
Fresnel zone diameter D: about 1.2 m
If you cannot set up the Fresnel zone, sometimes the available communication distance may be shorter than
usual due to obstacles inhibiting communication.
When installing on a metal plate or concrete wall, install the devices in the Fresnel zone so they are free of any obstacles.
