Example Applications - RFID: Fundamentals and Applications in Contactless Smart Cards and Identification - page 378

to a batch size of one, without having to set up a complex communication with the
central computer for each object.

• Harsh environmental conditions: RFID systems are completely insensitive to

dust, moisture, oils, coolants, cuttings, gases, high temperatures and similar prob-
lems that can occur in a manufacturing environment. Glass and plastic transpon-
ders usually comply with protection type IP67; that is, they are totally dustproof
and waterproof.
Even particularly dusty or dirty environmental conditions, which would make the
use of barcode readers impossible due to the rapid blocking of scanner optics, pose
no problems for RFID systems.

13.10.2.2 The selectionof a suitableRFID system

When selecting a suitable RFID system for use in the production process, the charac-
teristics of the different memory technologies should be considered (see Table 13.5;
see also Section 10.3).
EEPROM Data stored in an EEPROM is retained for several years without a power
supply. The energy required for writing to or reading from a transponder using EEP-
ROM technology is transmitted by inductive coupling. Since the transponders do not
require a battery they may be very small. The guaranteed number of write access oper-
ations to a memory address is typically around 100 000 cycles, which is greater than
the lifetime of the transponder. However, an innovative type of EEPROM technology
is now available on the market which can be reprogrammed more than 10 6 times. This

Table 13.5 Comparison between the two memory technologies for transponders

EEPROM/FRAM SRAM

Memory size 16 byte-32Kbyte 1-512Kbytes

Data transmission Inductive coupling Inductive coupling,

backscatter

Power supply Inductive coupling Battery

Typical number of
write cycles

EEPROM: 100 000-1 000 000
FRAM: 10 10

Unlimited

20 ◦ C-120 ◦ C 0 ◦ C-60 ◦ C

Typical temperature
range

−

Applications Applications with a limited

number of reprogramming
operations (EEPROM)

Applications with any
number of reprogramming
operations, e.g. in assembly
systems

Applications with expanded
temperature range

Use in the 'normal' industrial
temperature range

— Need for higher memory size

with short transaction time

— Large transponder range

required (or low positional
accuracy)