The following panel for setting the parameters
of symbolic addresses is shown:
Figure: Use of symbolic addresses
of S7 tags
With Accon-AGLink it is also possible to use
the symbolic addresses of the S7 tags.
CAUTION
Note that "|" should be used as separator
(to specify the length) instead of ":" . This also works
for normal addresses. For normal addresses also ":"
can be used.
The symbol browsing work when also when the peripheral
address had not been configured. That means that the symbol browser
does not depend on the S7 driver.
The searching (browsing) is divided into two processes:
Program selection
Item browsing
The symbolic addresses can only be browsed for
an S7 project, therefore the name of such a project has to be
specified. When the above panel is opened the first time, you
have to define the project name (which also defines the internal
data point name of type _S7_Symbolics).
Caution
Make sure that the project name, defined in
this panel, is the same like the defined project name in the STEP
7 program.
There can only be one project per PLC (_S7_Conn
data point). You can make the following settings in this panel:
Connection name
Several connection names
can be defined in a STEP 7 project. Specify a connection name
in this text field for filtering the data in the project or load
a program by clicking on the button Reload programs.
Filter
A filter can be set (to reduce the number of shown tags) in this
text field. This filter does not influence the browsing itself,
only the display.
Delete
symbolic
Deletes the corresponding data point of type _S7_Symbolics.
Reload items
Browsing is only then
possible when addresses are configured. Otherwise the button is
disabled.
The DPE DoBrowseSymbols
of the internal connection data point is set. The S7 project will
be browsed for tags. For each browsed S7 project a new internal
data point of the type _S7_Symbolics
is generated automatically from the panel. The name of the data
point is the name of the internal connection data point with the
suffix _<project name>
(for example _AG45_testproject). The driver fills the elements
of this data point after browsing, the panel shows the contents
of this data point.
Address translation
The translation from symbolic to normal address
is done based on the internal DP _S7_Symbolics
and on the selected project name on the internal DP _S7_Conn.ProjectName.
There could be several DPs for each PLC but only one project can
be selected at a time. The name of the _S7_Symbolics
data point consists of the PLC name (_S7_Conn
DP) and the project name (_S7_Conn.ProjectName).
The translation of the address is done in the driver.
Detailed information on the internal data points for the S7 driver
you will find in the chapter Internal
data points of the S7 driver.
Note
When the project name or the _S7_Symbolics
data point is changed, the driver must be restarted. This is necessary,
because otherwise the driver addresses might be inconsistent with
symbolic information. In that case the driver writes the following
error message in the Log Viewer:
”Driver restart required, for using changed symbol information
of project '<STEP7_project>'”
So the normal procedure, when working with Symbolic
would be:
Start
the driver.
Select
the project name by opening the Symbolic panel and enter the
value in the panel for the data point.
Select
the connection name from the combo box in the panel or reload
programs. If the program name is empty the symbols from all
programs are browsed.
Click
on Reload
items. This will last several seconds depending
on the size of the Step 7 project.
The driver
will update the corresponding S7_Symbolics
data point.
Restart
the driver to take the new table into account. Symbolic addresses
are always prefixed with a ”$” sign. This is necessary for
the driver to safely identify a symbolic address.
Note
For symbolic
addresses the transformation type must be correctly set. Default
is not allowed in this case, because the type cannot be
derived by parsing the string. This might be changed in a future
version.
Note
The driver will connect to the internal _S7_Conn data point only if
there is an address configured on that
S7 PLC. This means if there is not at least one address the browsing
of the S7 project will not work, because the driver does not get
the hotlinks for the _S7_Conn.ProjectName and the _S7_Conn.DoBrowseSymbols DPEs. |