Siemens SIMATIC RF600 Series System Manual page 51

4.3.8.3 Optimization of robustness of tag data accesses for readers that are operated
simultaneously
Parameter data access reliability
If several readers are to be operated simultaneously in an environment, then the following
settings affect the reliability of the reader's access to transponder data:
● Electromagnetic environment (see section "The response of electromagnetic waves in the
UHF band (Page 56)")
● Type of transponder (see section "Transponder (Page 289)")
● Number of transponders to be detected by an antenna at a time
● Type of antenna (see section "Antennas (Page 179)" and section "Guidelines for
selecting RFID UHF antennas (Page 52)")
● Transponders' distance from and orientation to antennas (see section "Transponder
(Page 289)")
● Distances and orientation of antennas of different readers to each other
● Radiated power of antennas
The robustness of transponder data access is improved for readers whenever distances to
adjacent readers are increased, radiated power is reduced, and a channel plan (for ETSI
readers) is implemented. Adjacent readers are parameterized in the channel plan such that
they cannot use the same channels.
A channel plan can be created for ETSI and CMIT readers; for FCC readers, it is assumed
that the probability of two readers accidentally using the same channel is very low.
4.3.8.4 Frequency hopping
This technique is intended to prevent mutual interference between readers. The reader
changes its transmission channel in a random or programmed sequence (FHSS).
Procedure for FCC
Frequency hopping is always active with FCC. With 50 available channels the probability is
low that two readers will be operating on the same frequency. In China, one reader operates
on at least 2 channels, e.g. sixteen 2 watt channels.
You will find more information on frequency bands in the section "Regulations applicable to
frequency bands (Page 83)".
Procedure for ETSI
Frequency hopping is optional with ETSI. According to ETSI EN 203 208 V1.4.1, frequency
hopping is used in multi-channel operation. Without frequency hopping, only single channel
operation is possible for which the standard specifies a pause of 100 ms after each 4 s of
sending.
SIMATIC RF600
System Manual, 10/2016, J31069-D0171-U001-A19-7618
RF600 system planning
4.3 Antenna configurations
51