VEGA VEGASCAN 850 Profibus DP signal output - Manual (Page 8)

8 Profibus DP signal output VEGASCAN 850
Operating mode VEGASCAN 850
4 Operating mode VEGASCAN 850
Two different operating modes are available
for VEGASCAN.
Depending on the operating mode,
VEGASCAN reserves a different number of
input and output bytes in the Profibus master.
4.1 Mode 50E2A
In this mode, VEGASCAN reserves 50 input
bytes and 2 output bytes.
The Profibus master has to process 50 Bytes
of data consistently.
How it works
A control command and a block number (1
byte each) are written into the 2 Byte output
data. After VEGASCAN has received these
two Bytes via Profibus DP, it answers by
sending the data of the required block these
50 Byte are then available to the Profibus-
Master as input bytes.
Since a maximum of 60 PC/DCS values is
available in VEGASCAN, but only 50 bytes at
a time can be transferred on the Profibus, the
data are multiplexed on the bus.
To facilitate this, the data are divided in
VEGASCAN into blocks. The requested block
can be enquired by the Profibus-Master with
the control command and the block number.
8 PC/DCS values (6 Byte each), the control
command (1 Byte) and the block number (1
Byte) decremented by the value 1 are re-
turned in a block.
4.2 Mode 6E6A
In this mode, VEGASCAN reserves 6 input
bytes and 6 output bytes.
The Profibus-Master must process 6 Byte
data consistently.
How it works
A control command and a PC/DCS value
number (1 Byte each) are written by the
Profibus-Master into the 6 Byte output data,
the remaining 4 Byte must be filled with the
value 0xFF.
After VEGASCAN has received these 6 Byte
via the Profibus DP, it answers by sending
the data of the enquired PC/DCS value.
These 6 Byte are then available as input
bytes to the Profibus-Master.
Since a maximum of 60 PC/DCS values are
available in VEGASCAN, but only 6 bytes at a
time can be transferred on the Profibus, the
data are multiplexed on the bus.
To facilitate this, the data in VEGASCAN are
divided into single PC/DCS values. With the
control command and the PC/DCS value
number, the Profibus-Master can enquire the
respective PC/DCS value.
4.3 Selection of the operating mode
To select the operating mode, it is necessary
to choose the respective configuration when
creating the bus configuration. The GSD file
provides both operating modes as options.
The selection is made with the respective
configuration tool, e.g. HW-Config for SIE-
MENS S7 systems or COM PROFIBUS for
SIEMENS S5 systems.
Depending on the configuration tool, a win-
dow is opened in which the desired operat-
ing mode can be selected when adding a
VEGASCAN slave to the bus configuration.