Case Structure Voltage Initiation

[CINATAS]

I would like to execute a program located inside a case structure with a voltage. Is their a sub vi I can use to do this with? I would like the case structure to be in the true state when a 5v digital volatage is recieved, the voltage would remain on and the program inside the case structure would execute. When the voltage is not present, the case structure would be in the false state. Is this possible? If so are thier any examples available? Thanks.

[Dennis_Knutson]

What kind of hardware do you have to measure the 5 volts? If you have a DAQ board, then you would use the DAQ functions. If it's a GPIB instrument, then you use a driver that you download or write. If you want to hook up the signal to the parallel port you can read the logic state of the parallel port's data pins. It all depends on what type of physical interface you intend to use.

[CINATAS]

The voltage would be digital 5V from a plc.

[CINATAS]

Hardware is scb-68 connector block and a pci-6220.

[Dennis_Knutson]

You can use either an analog or digital input of the DAQ board to read the signal. There are a lot of shipping examples of using DAQmx to read either a voltage or digital signal. For example, if using digital I/O, the output might be a True/False or 1/0. Either one of these can be wired directly to a case statement. For an analog read, use the comparison function to see if the value is greater than 3.5 volts and wire that to the case statement.