Displaying a text on a TP177b, without a script

I have the following problem.

When the user presses a start button (not on the screen) and there is no ventilation, then the TP should display a message, saying that the user should first start the ventilation.

First I thought of solving this through a script :
When the button is pressed, check if the ventilation is on, if so then start the machine. If not then display a messagebox.

But since my TP (177b) doesn't support scripts, I have to find another way.

Any1 have any suggestions?


thx in advance for any help.

What you describe is normally part of the PLC program.
The PLC program can then trigger a message on the HMI.
Even if your panel supported scripts, I would advice you to use scripts very sparingly.

And how do I trigger a message?