Balluff BIS M-4008-048-0 ST4 PROFINET Series, Operating Manual, Page: 56 / 232

BIS M-4008-048-0xx-ST4
PROFINET
8
The compact processor unit is the link between data carrier and host system. It manages two-
way data transfer between data carrier and compact processor and provides buffer storage.
The compact processor unit writes data from the controlling system to the data carrier or reads
the data from the data carrier and makes it available to the controlling system.
Controlling systems may be the following:
– A PLC.
Double bit string:
In order to ensure complete transmission of all data in the data buffer, the control bits in the data
buffer's first and last byte (bit header) are transmitted and compared. If both bit headers are the
same, then the data is updated completely and can be taken over. This means that the data for
each R/W head is only valid if both bit headers are the same. Thus, the host system also has to
compare the bits in the bit strings.
In order to increase data integrity, data transfer between the data carrier and
compact processor as well as the storage device can be monitored using a check procedure.
A CRC_16 data check can be enabled for this via parameter configuration.
With the CRC_16 data check, a check code that allows the validity to be checked at any time is
written to the data carrier.
A CRC_16 data check provides the following advantages:
– Data integrity even during the non-active phase (data carrier outside the R/W head).
– Shorter read time – page is read once.
Open bus system for process and field communication in cell networks with few nodes and for
data communication in accordance with IEC 61158/EN 50173. Automation devices, such as
PLCs, PCs, operating and observation devices, sensors or actuators, can communicate using
this bus system. PROFINET IO is used in the BIS M-4008.
Process data (cyclical):
The GSDML file provides combined input/output modules (8 bytes…254 bytes) to map the
sensor image:
– Combined input/output modules (8 bytes…254 bytes)
Service data (diagnostics, parameters):
– Parallel and non-reactive to process data
3.3 Control function
3.4 Data integrity
3.5 PROFINET
3.6 Communication
Mode
3
Basic Knowledge