VEGA VEGACOM 557 Profibus DP - Manual (Page 80)

80 VEGACOM 557 Profibus DP
Sync and Freeze mode
In addition to the participant-related useful
data traffic, handled automatically by the
DPM1, it is possible for the DP Masters to
send control commands to a Slave, a group,
or to all DP Slaves together . These control
commands are transferred as multicast func-
tions. With these control commands, the Sync
and Freeze modes can be preset for the
synchronisation of the DP Slaves. They en-
able an event-driven synchronisation of the
DP Slaves.
The DP Slaves start the Sync mode upon
receipt of a Sync control command from the
allocated DP Master .
Analogue to this, a Freeze-control command
activates the Freeze mode of the contacted
DP Slaves.
Open planning
For the Pr ofibus DP, the characteristics of the
instruments are documented by the manu-
facturer in the form of a data sheet and an
instrument master file which are made avail-
able to the users. Structure, contents and
coding of these instrument master data
(GSD) are standardised. The PNO archives
this information (multivendor) and upon re-
quest, provides information on the GSD.
Each DP Slave and each DPM1 must have an
individual ID number . This number is r equired
for identification of the connected instrument
types (without significant protocol overhead)
by the DP Master .
The manufacturers have to apply for an ID
number for each DP Slave and each DPM1 at
the PNO. The PNO administrates the ID num-
bers together with the instrument master
data.
Mixed operation with Profibus FMS
The common operation of Profibus FMS and
Profibus DP components on one bus is a
special advantage of PROFIBUS. For appli-
cations with reduced demands on system
reaction time, the mixed operation of Profibus
FMS and Profibus DP components is possi-
ble and useful on one bus. Even the simulta-
neous operation of both protocol versions in
one instrument is possible. These instru-
ments are called mixed instruments. Mixed
instruments offer advantages for the manu-
facturer and the user .
The mixed operation is possible, because
both protocol versions use unique transmis-
sion and bus access procedures (layer 1/2).
The different application functions are sepa-
rated by different service access points of
layer 2.
Further information
The PNO represents the Profibus interests of
the manufacturers and user and coordinates
the maintenance and further development of
the Profibus standard.
Chart 1: Master-Master functions with Profibus DP
Function Meaning DPM1 DPM2
Get_Master_Diag Reading of the diagnostic data of the DMP1 or the collective diagnostics MO
of the DP Slaves
Download / Loading or reading of the complete configuration data of a DPM1 O O
Upload group and the respective DP Slaves
(Start_Seq, Download /
Upload, End_Seq)
Act_Para_Brct
Activation of the bus parameters together for all responded O O
DPM1 instruments.
Act_Param Activation of parameters or modifications of the operating condition O O
on the responded DPM1 instrument.
M: mandatory, O: optional
Supplement C