Operation Of Several Readers Within Restricted Space; Dense Reader Mode - Siemens SIMATIC RF600 System Manual

4.3.7

Operation of several readers within restricted space

4.3.7.1

Dense Reader Mode

A special operating mode for Gen 2 tags enables several RF600 readers to be operated
without interference in close proximity to each other. This applies to all RF600 readers:
RF660R, RF630R and RF620R.
Dense Reader Mode (DRM)
In this mode, tag readability is increased through the application of interference-reducing
measures.
DRM is only defined for Gen 2 and does not function with other tag types.
Operating principle
Dense Reader Mode allows physically adjacent readers to use the same frequency when
Gen 2 tags are being used.
In accordance with EPC Global as well as ETSI EN 302 208 V1.1.2, only the even channels
are used for transmitting in this mode (communications path Reader -> Tag) with the
RF660R; the tag response is on the odd channels as a result of the frequency offset. In
accordance with EPC Global as well as ETSI EN 302 208 V1.2.1, the four transmit channels
are used for transmission with the RF620R/RF630R (see Section Regulations for UHF
frequency bands in Europe (ETSI EN 302 208 V1.2.1) (Page 62)) and the tag response
appears on all channels. As a result of the large difference in level between the transmitter
channels and the tag response channels, this technology provides great advantages for
frequency reuse. However, a prerequisite is that a certain minimum distance, and thus
minimum decoupling, is observed between the antennas of adjacent readers.
SIMATIC RF600
System Manual, 10/2009, J31069-D0171-U001-A8-7618
RF600 system planning
4.3 Antenna configurations
51