Simulating PROFIBUS devices with CX7031
The CX7031 can simulate up to four PROFIBUS devices. It should be noted that the CX7031 can only simulate the GSD file, but not the actual function or logic. Timings are also not part of the simulation. The user must therefore take care of this himself and is also responsible for the application. The number of process data as well as parameter and configuration data must not exceed 240 bytes in total.
The parameter and configuration data are always confirmed without errors. However, it is possible to redirect these two data packets to the PLC for evaluation and, if necessary, to change the process data or function.
Proceed as follows:
- 1. Insert the GSD file that you want to simulate into the folder \TwinCAT\3.1\Config\Io\Profibus.
- 2. Activate the Allow all GSD files option to activate this function.
- 3. Insert the PROFIBUS device to be simulated into the structure tree. The input data is then regarded as output data and vice versa, as the data direction changes. The GSD file shows the data from the master's point of view. However, as the GSD file is viewed from the slave's perspective, the data direction is reversed.
Example: The GSD file contains an INT variable that displays the temperature value of a PROFIBUS slave. In the simulation on the CX7031, this value is determined via an EL3312, which is connected to the terminal as an input and forwarded to the PROFIBUS interface as an output. The value then appears again as an input on the PROFIBUS master side.
The picture shows a simulated BK3100 with an analog input terminal. An analog output is required to link the data for the input (from the master's point of view).