Siemens SIMATIC RF300 System Manual page 83

Interference sources
In order to achieve a high level of electromagnetic compatibility and thus a very low level of
disturbance in a plant, it is necessary to recognize the most frequent interference sources.
These must then be eliminated by appropriate measures.
Table 4- 26
Interference source
Contactors,
electronic valves
Electrical motor
Electric welding device
Power supply unit, switched-
mode
High-frequency appliances
Transmitter
(e.g. service radio)
Ground or reference potential
difference
Operator
Power cable
High-voltage cable
What interference can affect RFID?
Interference source
Switched-mode power supply Interference emitted from the
Interference injected through
the cables connected in
series
HF interference over the
antennas
SIMATIC RF300
System Manual, 01/2009, A5E01642529-03
Interference sources: origin and effect
Interference results from
Contacts
Coils
Collector
Winding
Contacts
Transformer
Circuit
Circuit
Antenna
Voltage difference
Static charge
Current flow
Voltage difference
Cause
current infeed
Cable is inadequately
shielded
The reader is not connected
to ground.
caused by another reader
RF300 system planning
4.7 EMC Directives
Effect on the interference sink
System disturbances
Magnetic field
Electrical field
Magnetic field
Electrical field
Magnetic field, system disturbance,
transient currents
Electrical and magnetic field, system
disturbance
Electromagnetic field
Electromagnetic field
Transient currents
Electrical discharge currents, electrical
field
Electrical and magnetic field, system
disturbance
Electrical field
Remedy
Replace the power supply
Better cable shielding
Ground the reader
Position the antennas further
•
apart.
Erect suitable damping materials
•
between the antennas.
Reduce the power of the readers.
•
Please follow the instructions in the
Installation guidelines/reducing
section
the effects of metal
83