GPIB Troubleshooting

This section should be used for troubleshooting a test station's GPIB configuration when a problem is indicated.

Manual Check of GPIB Bus Devices (Keysight/Agilent/HP GPIB)

1. Start the Visa Assistant:

   • Click the hp box or the IO box on the right side of the task bar, or access it through Start > Programs > HP I_O Libraries > Visa Assistant.

2. Check for all expected GPIB devices:

   • Verify that all of the expected GPIB devices are shown in the left window. If a device is missing, correct the problem and restart VISA Assistant.

3. Check for basic operation of each GPIB devices:

1. Click the desired GPIB device to highlight it.

2. Click the Formatted I/O tab (expand the window if needed).

3. Click SCPI > *IDN?.

4. The model, serial number, and firmware revision should be represented in the response string. Check to see that the expected model number is contained in the response text string.

   This will not work with the Dynamic Accuracy Test Set or the Gain Compression Test Set.

4. Check for detectable options on a given device:

   1. Click the desired GPIB device to highlight it.

   2. Click the Formatted I/O tab, then click SCPI.

   3. Enter *OPT, then click viQueryf.

   4. Each expected option should be represented in the response string. A detectable option is one that can be detected via the GPIB.

      This will not work with the Dynamic Accuracy Test Set or the Gain Compression Test Set.

5. Check communication with the Dynamic Accuracy Test Set or Gain Compression Test Set:

   1. Click the desired GPIB device to highlight it. Click the Attributes tab.

   2. Click to open INSTR Resource Attributes, then click to open Generic INSTR Attributes.

   3. Highlight VI_ATTR_TERMCHAR. Change the current value to 0x0D, then click Set.

   4. Highlight VI_ATTR_TERMCHAR_EN and change the current value to VI_TRUE, then click Set.

   5. Click the FORMATTED I/O tab, set the SCPI radio button, enter sn?, then click viQueryf. (This should return the serial number of the test set.)

Manual Check of GPIB Bus Devices (National Instruments GPIB)

1. Start the NI MAX (Measurement Automation Explorer):

   • Go to Start > Programs > National Instrument > Measurement & Auto....

2. Check for all expected GPIB devices:

   • Verify that all of the expected GPIB devices are shown in the left window. If a device is missing, correct the problem and rescan for instruments.

3. Check for basic operation of each GPIB device:

   1. Right click the desired GPIB device to highlight it. Select Communicate with instrument to open a new window.

   2. Send a "*IDN?" query.

   3. The model number, serial number, and firmware revision should be represented in the response string. Check to see that the expected model number is contained in the response text string.

      This will not work with the Dynamic Accuracy Test Set or the Gain Compression Test Set.

4. Check for detectable options on a given device:

   • Send a "*IDN?" query. Each expected option should be represented in the response string.

   • A detectable option is one that can be detected via the GPIB.

   This will not work with the Dynamic Accuracy Test Set or the Gain Compression Test Set.

5. Check communication with the Dynamic Accuracy Test Set or Gain Compression Test Set:

   1. Open VISA Interactive Control via the Program menu. (This is a separate program from the NI MAX used above.)

   2. Double click on the appropriate GPIB instrument. A new window will open specifically for that GPIB interface.

   3. Under the Template tab, select the viSetAttribute tab.

   4. Process for changing an attribute:

      1. Select the desired attribute name.
      2. Select or enter the new value.

      3. Click the Execute button to make the change effective.

   5. Enter new values for the following attributes:

      • VI_ATTR_TERMCHAR = xD

      • VI_ATTR_TERMCHAR_EN = VI_TRUE

   6. Select the Basic I/O tab which will allow you to read and write to the GPIB interface.

      Be sure to terminate write strings with: \n Example: Type the following into the viWrite buffer: sn?\n Click the Execute button. Select the viRead tab, then click the Execute button to view the response.