Communication Errors

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.

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);

Refer to your instrument's documentation to determine which, if any, termination characters to use.