GPIB Read Successful; Write Fails

Updated Feb 14, 2018

Reported In

Driver

  • NI-488.2
  • NI-VISA

Issue Details

I can communicate with my GPIB instrument through NI MAX, but only the Read commands return information successfully.  The Write commands do not seem to work. How can I get around this?

Solution

This likely is a result of an incorrect termination character.  Consult your product's manual for the termination character for each and then use the configuration utility for your platform if you need to change the termination character.

To determine the termination mode for a given instrument, refer to its manual. As a rule of thumb, all IEEE 488.2 devices terminate on and assertion of the EOI (End Or Identify) line in the GPIB bus.

Additional Information

When GPIB Write.vi executes, the computer is in talk mode and the instrument is in listen mode. When GPIB Read.vi executes, the device is supposed to switch to talk mode and the computer to listen mode. The device is prompted to switch modes by a termination signal which may be a character (End Of String) or a GPIB bus line (End Or Identify). If GPIB Read.vi times out or returns an EABO (Operation aborted) error, it means that the device is not receiving the right termination signal. 

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