National Instruments NI-488.2 - Manual (Page 60)

Chapter 5 Debugging Your Application
© National Instruments Corporation 5-3 NI-488.2 User Manual
Communication Errors
The following sections describe communication errors you might
encounter in your application.
Repeat Addressing
Devices adhering to the IEEE 488.2 standard should remain in their current
state until specific commands are sent across the GPIB to change their
state. However, some devices require GPIB addressing before any GPIB
activity. Therefore, you might need to configure your NI-488.2 driver to
perform repeat addressing if your device does not remain in its currently
addressed state. You can either reconfigure from your application using
ibconfig , or reconfigure using Measurement & Automation Explorer.
Note National Instruments recommends using ibconfig to modify the configuration.
If your application uses ibconfig , it works properly regardless of the
previous configuration. For more information about ibconfig , refer to
the description of ibconfig in the NI-488.2 Help. For instructions on
accessing the online help, refer to the Using the NI-488.2 Documentation
section in About This Manual .
Termination Method
You should be aware of the data termination method that your device uses.
By default, your NI-488.2 software is configured to send EOI on writes and
terminate reads on EOI or a specific byte count. If you send a command
string to your device and it does not respond, it might not be recognizing
the end of the command. In that case, you need to send a termination
message, such as <
CR > < LF >, after a write command, as follows:
ibwrt(dev,"COMMAND\x0D\x0A",9);
Other Errors
If you experience other errors in your application, refer to the NI-488.2
Help. It includes extensive troubleshooting information and the answers to
frequently asked questions. For instructions on accessing the online help,
refer to the
Using the NI-488.2 Documentation section in About This
Manual .