Vishay G4, Техническое руководство, Страница: 113 / 200

G4 Multi Channel Weighing Instrument
6-9
blocks. Note that the set-up and use of the Fieldbus interface (Profibus-DP or
DeviceNet) is completely separate and independent from the EtherNet/IP interface.
Instance 100 is used to control the instrument and set-up certain values, like levels and
set points in the instrument. If used in a class 1 connection it will be exclusively owned
by this connection (only one can write to instance 100)
Instance 101 can be used if only the base data block is of interest and not the
configurable data blocks.
Instance 102 contains only configurable data blocks. This instance is convenient to use
if the base data blocks is not of interest. The actual data size depends on the
instrument settings, which defines the usage of the data blocks that should be used.
Instance 103 should be used if the complete set of data is needed. The actual content
depends on the instrument settings, which defines the usage of the data blocks.
Instance 190 is a so called Heart Beat instance, which can be used instead of instance
100 if no control of the instrument is desired.
Ftp Server
The G4 instrument contains an ftp server that can be used to transfer files between the
instrument and an external computer using an ftp client. To connect to the instrument
the ftp client must login to the instrument with the user ID ‘G4User’ and the password
‘1937’ (default password). Note that the password for the ftp server and the web server
can be set in the menu ‘Server Configuration’. In this menu there are also settings for
turning on or off the ftp server and web server. By default both ftp server and web
server are turned on.
The ftp handling can be automatic, e.g. to collect log files once every 24 hours or
manual.
The ftp client (on an external computer) can access the user area of the instrument
flash file system. The user area consists of (by default) the InstrBackup, Misc, Recipes
and LogFiles folders.
In the current instrument version the InstrBackup folder is used by default when
creating backup files. The LogFiles folder is used for storing Scale batching log files.
Modbus protocol
For communication with a master computer (PLC) the Modbus protocol is used in
the instrument. The Modbus protocol is a standard protocol, used for master/slave
communication in the industry.
Information is transmitted in blocks of data to minimize polling and response time
delays. For example the error register, status register and weight register could be read
with one command to the instrument.
When a command that cannot be performed is sent, the instrument responds with
an exception code. For a better explanation of the error, a special command error
register could be read.
Depending on the type of the communicating equipment (the master), the commands in
the application programme (PLC programme, or pc programme) may be different from
type to type. However, if the master is not a Modicon PLC system, then the Modbus
implementation in the master must have some cross-reference function to transfer the
Modbus register and I/O bit numbering to the masters own register and
I/O bit numbering. All registers and coils described in this manual use the standard
Modbus (Modicon) register and I/O numbering.