There are different ways to using timing with LabVIEW. How are you interfacing with your hardware? Do you have a DAQ board or a switch? What are you using to provide the current?
Depending on your hardware, there may be several options. Some options include the timed loop or sequence, a timer (i.e. wait ms) inside a while loop, external signals to trigger an event, or hardware timing for a daq task (analog or digital).
If you do not require precise timing (i.e. your load can be on for approximately 1 minute, 55-65 seconds is fine) then the simplest option would be to using the timing functions or timed structures. To learn about these functions use context help (CTRL+H) or LabVIEW help for the functions in your structures pallette (timed structures) and your timing pallette.
If you would like a more detailed suggestion, please post information regarding what hardware you are using and what signals you would like to control from LabVIEW.
Jennifer O. Applications Engineer National Instruments