If you use a macro program, you can read the time variable. When the time is longer than 15: 30, let the program skip machining all the time, so that even if the program runs circularly, the parts will not be machined, but such a discerning person can see it at a glance. Another kind of concealment is to modify the ladder diagram and add a signal to limit your start button. After this time, the start button is invalid. This method is generally not an expert can remove! No explanation, I thought the machine tool was broken (in fact, the hardware itself is fine)