Balluff BIS M-4 045 0 07-S4 Series, Operating Manual

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22
4
Basic Knowledge
To ensure data integrity, data transfer between the data carrier and read/write device can be
monitored using a CRC_16 data check.
With the CRC_16 data check, a checksum is written to the data carrier which enables the data
to be checked for validity at any time.
Advantages of the CRC_16 data check:
– Very high data integrity, even during the non-active phase (data carrier outside the read/write
head)
Restrictions of the CRC_16 data check:
– Longer write times, as the CRC must also be written.
– User bytes are lost on the data carrier
(see table on page 23) .
Use of CRC_16 can be configured by the user (see chapter „7.2 Mapping of Parameter Data“
auf Seite 44) .
The Autoread function is used to immediately read out a specific memory area of the data carrier
when the data carrier enters the vicinity of the read head. The data quantity here is 8 bytes (BIS
M-4_ _-045-...) or 30 bytes (BIS M-4_ _-072-...), the start address can be configured in the
parameters.
If a read error occurs during autoread or if the specified data area lies outside the capacity of the
data carrier, no error is displayed. In this case, no data is output.
4.5 Data integrity
4.6 Autoread
BIS M-4 _ _ IO-Link Device
Read/Write Device