We send exactly the commands according to the techincal docs we have from Aqua Illumination.

When they meanwhile changed their protocol without notifying us I would be irritated a little bit, but I can`t imagine this, they know that we spent a lot of time in programming the AI-interface for the ProfiLux.

Of course you can connect a PC RS232 interface in parallel to check what happens during communication, you will see the sent commands for example with a terminal program.
But I doubt that this will help us to find the source of the problem.