How do I send voltage through the serial port?

[JLS]

Hello,

I will assume you are referring to an RS-232 serial port.

When you transmit a given serial frame, you are really modifying the voltage on the transmit pin/line.  The characters you define sending (the string) will define the frame format, and the baud rate will define the rate at which the bits in the frame is clocked out.  This gives you the ability to send voltage waveforms, of course, somewhat restricted by the fact that there are stop bits, a start bit, and a parity bit sent with a given frame; in general you can define the data bits (usually 😎 to be anything by writing the corresponding ascii character.  If you want to programmatically send wither high or low voltage on a single line, you can do this by asserting and deasserting the RTS line.  In LabVIEW you can do this with the NI-VISA API; see the VISA Property Node to get access to (de)assterting the RTS line.

Repost if you have any further questions,

JLS

[RS05]

I am using a data board that communicates using ascii.  I try to connect. LabView acknowldges but says that the device is missing functionality.

[Dennis_Knutson]

You had posted the same question in the Instrument Control forum (which is the correct one - not Digital I/O) but I'll try to answer you here. What are you using to connect? The only functions you should be using are the serial functions (VISA Write, VISA Read, etc.)  on the Instrument I/O>Serial palette. This is assuming that the only connection between your board and the pc is a serial cable. How does LabVIEW acknowledge and what function is returning the "missing functionality" message? Provide some more information such as the make and model of your data board, interface type, etc.