How do I program the Instrument I/O Assistant to read a variable in the input string? I can manually type in the string using the Instrument I/O Assistant using the "Write" or "Query" tools but I do not know how to send a variable input to the Instrument I/O Assistant so that variable can be used inside the "Write" string. For example, I have a power supply whose current I want to set to X Amps. I can type the command "PC10" to program the current to 10 Amps, however I want to be able to program it at any arbitrary current. How do I feed the value X into the code for this purpose?