PLC Programming

9 - DDE Communication with CoDeSys
Dialog for configuring the GatewayDDE Server
Motorola byteorder
Check identity
Updaterate [ms]
Timeout [ms]
Tries
Motorola Byteorder is used
It will be checked, whether the project ID given by the symbol file is
the same as that stored in the PLC.
Time interval for reading all symbol values from the PLC.
Communication timeout for the used driver.
Number of retries of the communication driver to transfer a data
block (not supported by all drivers !)
To set up the connection to the Gateway, the dialog 'Communication Parameters' is opened by the
command 'Online' 'Parameters'. It is the same dialog as you get in CoDeSys with the command
'Online' 'Kommunikationsparameter'. The settings you do here must be the same as in the
corresponding CoDeSys Project.
The actual configuraiton of the GatewayDDE Server can be stored in a file by the command 'File'
'Save'. The standard dialog for saving a file will open, default for the extension of the file is *.cfg.
To get the gateway in active mode, login by the command 'Online' 'Login'. (The gateway symbol in
the status bar will get lightened then.) At login the desired connection will be built up and the available
symbols can be accessed.. These must have been created before in the CoDeSys Project !
To log out use the command 'Online' Logout'.
General Approach to Data
A DDE inquiry can be divided into three parts:
1. Name of the program (here: CoDeSys),
2. File name and
3. Variable name to be read.
Name of the program: CoDeSys
File name: complete project path (c:\example\example.pro).
Variable name: The name of a variable as it appears in the Watch and Receipt Manager .
Which variables can be read
All addresses and variables are readable. Variables or addresses should be entered in the format
used in the Watch and Receipt Manager
Examples:
%IX1.4.1 (* Reads the input 1.4.1*)
PLC_PRG.TEST (* Reads the variable TEST from the POU PLC_PRG*)
CoDeSys V2.3 9-3