Serial Communication Failure

This section contains information that applies to Windows and Linux, not Windows on ARM.

Problem:

Connection Expert cannot successfully verify a device connected via serial (RS-232) port.

Probable Cause:

A mismatch of communication parameters between Connection Expert and the instrument can prevent successful communication.

Another Windows process may have opened the serial port.

Suggested Steps:

  1. Check the physical connection to your instrument. Ensure that you are using the correct cables. Select the serial instrument from the My Instruments list (Edit the Instrument details). Ensure that the instrument is shown to be connected to the same serial port that it is really connected to.

    • The instrument's VISA interface ID should indicate the serial port it is connected to: for example, ASRL3 for the COM3 port. If it does not, change it to the correct port.
    • Note that some serial ports may actually be mapped to modems or other devices in Windows, and in that case you cannot successfully add instruments to those ports. If attempts to verify the connection using the Test This VISA Address button fail, you may have added the instrument to a modem port. Change the VISA interface ID to correspond to the RS-232 port the instrument is actually connected to.

  2. Compare each property value in the Edit view to the corresponding value on your instrument. This is typically done with front-panel menu selections; consult the instrument's documentation. Change the values in Connection Expert to match those set on the instrument.

    3. Note that in a few cases, you may not be able to match the instrument properties in Connection Expert. For example, Connection Expert does not support a 600 baud connection speed. If you encounter such a case, then change the instrument's connection properties using front-panel selections to match the Connection Expert values.

  3. Click OK to save any properties you have changed.

  4. Close any other Windows applications that may be attempting to use the serial port. This may include applications (for example, Microsoft ActiveSync) that are not using the serial port, but that occasionally open the port to poll or check for connections. You may be able to change the configuration of such applications so that they do not use serial ports you need for your instruments.

    Refer to the Connection Expert help regarding manually adding an instrument. Open the help from IO Control.