15
Attention
Take care that the naming convention is IEC 61131-3 compatible (no special characters,
...); otherwise the button Finish will not be available in the dialog. See also:
Variable
names
(on page 19)
Info
The variables declared in zenon are always entered in the Global area of the variable list in
straton.
3.5.3
Using zenon variables in straton
It is very easy to further process variables from PLC systems such as e.g. Siemens S7 or Beckhoff
TwinCAT in straton, variables which were read in by the according zenon drivers in zenon.
One possibility to realize this functionality is the allocations (see Allocations). The variable from the PLC
(e.g. S7 ) is linked to a straton variable with an allocation. In this case only a unidirectional
communication is possible.
PLC variables (e.g. from a S7) can be exchanged between zenon and straton via a shared memory
connection bidirectionally (!), easier and quicker . In the properties of the PLC variable the flag
Externally visible has to be set to make the variable available in the straton Workbench.
16
As soon as this flag is set, the variable is displayed in the variable list of the straton Workbench.
17
Attention
Regard interactions with property Hysteresis:
If a Hysteresis was configured for the zenon variable, the value in straton does not match
the value in the PLC. It is also possible that it does not match the value in zenon:
If the value changes in the PLC and stays within the configured hysteresis, it is not communicated
to the zenon Runtime and therefore also not to straton.
If the value is changed by the user in zenon (e.g. via a function) and the value stays within the
configured hysteresis, the value remains the same in zenon and in straton but it changes in the
PLC.
If the value is changed in straton and stays within the hysteresis, the value in the PLC and in
stratonchanges. It remains however the same in zenon.
If in this situation the value changes in the PLC and stays within the hysteresis, three different
values exist.
one in the PLC, one in zenon and one in straton.
Such a variable is especially marked in straton, as it cannot be changed in straton. Changing the variable
here would lead to problems, as the source of the variable is the PLC programming environment in the
external PLC (e.g. S7).
Attention
Be careful with the variable name! The name of the variable from an external PLC has to
be IEC 61131-3 compatible. Also see
Variable names
(on page 19).
18
In straton a so-called I/O driver - shared memory driver - must be loaded in order to make the
communication for such variable possible in the Runtime.
In order to do this open the fieldbus configuration in the straton Workbench with
File -> Open... ->
Fieldbus configuration
.
The following dialog opens with the menu
Insert -> Insert configuration...
:
Here select the configuration
straton to zenon-RT
connection. So this configuration is inserted in
the tree of the fieldbus configuration:
Now it is guaranteed that the externally visible variables from zenon communicate with straton.
Info
Please be aware, that such a connection only works locally on a PC or a CE device. Here it
is not possible to communicate with a straton Runtime on another device.
With the help of the zenrt driver complex variables (arrays and structure variables )are resolved into a
flat structure. The values of variables with the same name in straton and zenon are exchanged via the
shared memory driver.
19
Info
The functions for checking the status of a variable and for setting Dirty are not supported
at the moment.
The status information (time stamp and status bits) are not supported for complex data
types.
If you marked an element of an array or a structure variable as externally visible, a simple variable with
the same name is created in the straton Workbench. If you marked the array or the structure variable
itself as externally visible, this complex variable is created in the workbench.
Info
If you mark an array or a structure variable as externally visible, the individual elements are
not created in the Workbench anymore.
You can create variables in the workbench, which contain characters '.' or '[]' in their
name. Therefore you can create variables which have the same name as variables which
derive from an array or a structure variable. In this case the communication with the zenrt
driver is not possible as no distinct allocation can be made.
3.5.4
Variable names
In straton variable names must be in accordance with the IEC 61131-3 regulations. The correctness of
the entry is checked by zenon as well as by straton (communication take place using the STRATON32
driver).
For variables of other drivers (e.g. S7 TCO/IP driver), the engineer has to check that the variable name
fulfills the regulations of the IEC 61131-3 (communication takes place using shared memory).
_XYZ
__XYZ
Twice with Underscore
xy_z
xy__z
Twice with Underscore