Commissioning and configuration
100
BCL 504
i
Leuze electronic
10
Commissioning and configuration
Attention Laser!
Observe the safety notices in chapter 2!
10.1
General information on the PROFIBUS implementation of the
BCL 504
i
10.1.1
Communication profile
The
communication profile
defines how participants serially transmit their data via the
transmission medium. The
BCL 504
i
supports the communication profile for automation
systems and
D
ecentral
P
eriphery ->
PROFIBUS DP
.
DP communication profile
The
PROFIBUS DP
communication profile is designed for efficient data exchange on the
field level. Data exchange with the decentral devices occurs primarily cyclically. The neces-
sary communication functions are defined in the
DP
base functions. The
DP
optionally offers
acyclic communication services as well. These are used for configuring, operating,
observing and alarm handling.
In order to be able to perform data exchange, services are defined which
PROFIBUS DP
differentiates between on the basis of the data access points transmitted in the telegram
header.
The BCL 504
i
profile is based on the PROFIBUS profile for identification systems.
10.1.2
Bus-access protocol
The PROFIBUS communication profiles (DP,FMS) use a uniform bus-access process. It is
implemented by layer 2 of the OSI model. The bus-access control (MAC) defines the
process for specifying the point in time at which a network device can transmit data. It must
ensure that no more than one participant has permission to transmit at any given time. The
PROFIBUS bus-access process includes the token-passing process and the master-slave
process.
Process
Description
BCL 504
i
Token-passing
process
With this process, the bus-access permission is distributed
by means of a token. The participant obtains permission to
transmit with the token. The token wanders between the
master devices in the ring in a permanently defined time
frame. This type of bus access is used for communication
between the masters.
No
Master-slave
process
Various slave devices are assigned to a master. The master
can address the slaves which are assigned to it and fetch
messages from them. The master always has the initiative.
Yes
Table 10.1:
PROFIBUS bus-access processes