0203-02 Debugging Using Trace

Example Projects > 0203 Function Blocks REXLANG > 0203-02 Debugging Using Trace

Debugging REXLANG code using Trace() function

This example project illustrates how the user-defined code within the REXLANG function block can be debugged. The algorithm cannot be stopped, therefore the only possibility is to print debug messages to System log.

The algorithm counts pulses (rising edges) at the u15 input and writes messages to System log. The messages can contain both strings and numeric values. If an integer numeric value is written to System log, it is displayed in both decimal and hexadecimal format. It is also possible to manually force a message to be written.

Read the complete description of the REXLANG function block for more details.

Timing of the project

The algorithm runs each 100 milliseconds (0.1 s). See the EXEC function block,
tick x ntick0 = 0.05 x 2 = 0.1


  • REXYGEN Runtime Core must be installed and running on the target device.

Running the example

  • The *exec.mdl file is the project main file.
  • Open it with REXYGEN Studio, compile and download it to the target device.
  • Switch to Watch mode and observe the algorithm.
  • Make sure to configure system log to display all types of messages. Go to menu Target -> Configure System Log and tick all message types in the Function block messages section.
  • Make sure that the Logging checkbox is ticked in the REXLANG block properties dialog.
  • Display the system log. Go to menu Target -> Show System Log.
  • Toggle manually the BSTATE parameter in any of the MP blocks to force a message to be written.
  • Observe the messages appearing in the System log.


Additional information

  • See also the examples on integrating external devices for additional examples using the REXLANG function block
  • Visit the REXYGEN webpage for more information about the example projects and developing advanced automation and control solutions using REXYGEN.