Omron V680S-HMD64-PNT User Manual page 115

You can use communication diagnostic to detect and diagnoses deterioration of performance for the following
conditions.
Communications performance reduced by inclination of
RF Tags
Communications performance reduced by metal objects
Metal
Communications performance reduced by noise
Communications performance reduced by positional
offset of RF Tags
Communications performance reduced by an excessively
long communications ranges
Section 6
Functions
RFID System
113
User's Manual
(PROFINET)