I have a power supply connected to my PC via RS232. To this power supply I am able to send out a value (by labVIEW -- is already working). And I have another device connected by serial interface as well to my PC! There HF-pulses are generated and always if there is a puls generated (e.g. every ten seconds), I want to send out a value to the power supply (to set a certain current). After a certain period of time (e.g. two seconds) I want to reregulate the power supply, in order to set a new current until the next puls (trigger) is coming. So my power supply should switch between different values, controlled by LabVIEW and this external trigger. Thank you!