Siemens SIMOTRAS 6SG7050 Operating Instructions Manual page 115

01.04
The following diagram shows the services and channels supported by a CBP:
PKW
Job/
response
Slaves (e.g. CBP2) may only respond to received messages and are referred to as passive
nodes .
PROFIBUS ( Pro cess Fi eld Bus) combines high baud rates (to RS485 standard) with simple, low-
cost installation. The PROFIBUS baud rate can be selected within a range of 9.6 kbaud to 12
Mbaud and is set for all devices connected to the bus when the bus system is started up.
The bus is accessed according to the token-passing method, i.e. permission to transmit for a
defined time window is granted to the active stations (masters) in a "logical ring". The master can
communicate with other masters, or with slaves in a subordinate master-slave process, within this
time window.
PROFIBUS- DP ( D istributed P eripherals) predominantly utilizes the master-slave method and data
is exchanged cyclically with the drives in most cases.
The user data structure for the cyclic channel MSCY_C1 (see picture above) is referred to as a
Parameter Process(data) Object ( PPO ) in the PROFIBUS profile for variable-speed drives. This
channel is also frequently referred to as the STANDARD channel.
The user data structure is divided into two different sections which can be transferred in each
telegram:
PZD section
The process data (PZD) section contains control words, setpoints, status words and actual
values.
PKW section
The parameter section (PKW - Parameter ID Value) is used to read and write parameter
values.
When the bus system is started up, the type of PPO used by the PROFIBUS master to address the
drive is selected. The type of PPO selected depends on what functions the drive has to perform in
the automation network.
Process data are always transferred and processed as priority data in the drive.
Process data are "wired up" by means of connectors of the basic unit (drive) or via technology
board parameters, if these are configured.
Parameter data allow all parameters of the drive to be accessed, allowing parameter values,
diagnostic quantities, fault messages, etc. to be called by a higher-level system without impairing
the performance of the PZD transmission.
SIEMENS AG 6SG7000-0BA76
SIMOTRAS HD Operating Instructions
CPU
(Class 1 master)
MSCY_C1
MSAC_C1
Cyclic channel Acyclic channel
PPO DS 0
PZD Diagnosis
Setpoint/
actual values
Parameter channel
(Class 2 master)
Acyclic channel
DS 100
PKW PKW
Job/ Job/
response
response
Process data channel
DriveMonitor
MSAC_C2
PZD
Setpoint/
actual values
Start-up
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