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Chapter 4 Debugging Your Application
© National Instruments Corporation 4-5 NI-488.2 User Manual for Windows
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 the NI-488.2 Configuration utility.
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 online 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\x0A\x0D",9);
Other Errors
If you experience other errors in your application, refer to the NI-488.2
online 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.