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

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44
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 data capacity is sacrificed.
(see table on page 23) .
Note
The CRC_16 data check can only be used in combination with data carriers that have
been appropriately initialized. If a data carrier is not initialized and this parameter is
nevertheless set, CRC errors occur during reading and writing (see chapter 9.5 "Error
Codes" on page 58) .
The data carriers can be initialized for using CRC16 with command designator 12
hex
.
The checksum is written on the data carrier as 2 bytes (per block) of information. Thus, 2 bytes
of user data is lost per block.
The following figure applies for this parameter:
Index 40
hex
, subindex 1
hex
- 1 byte
00
hex
CRC_16 data check is not used (default setting)
01
hex
CRC_16 data check is used
If dynamic mode is activated, a job can be sent even if no data carrier is located in the read/write
range of the read/write head, which would result in errors without dynamic mode. The job is then
stored and is executed as soon as a data carrier is detected.
The following figure applies for this parameter:
Index 40
hex
, subindex 2
hex
- 1 byte
00
hex
Dynamic mode not activated (default setting)
01
hex
Dynamic mode activated
7.2 Mapping of
Parameter Data
CRC_16
Data check
Dynamic mode
7
Configuring the Read/Write Device
BIS M-4 _ _ IO-Link Device
Read/Write Device