Self test timeouts occurring for certain oscilloscope models in the Tektronix MDO/MSO/DPO family

We have received recent reports of timeout problems that occur during the automated self-test routine for certain models of Tektronix oscilloscopes in the MDO, MSO, and DPO families.  This self-test subprocedure will be updated by Fluke, then all associated MET/CAL Gold procedure packages will be rebuilt and released after testing.  If you are seeing self-tests that last longer than 20 minutes, and would like to apply your own immediate fix, I have provided two options to consider below.

The procedure that handles the self-test routine is "Sub Tek MDO/MSO/DPO Self-Test VISA" (currently at Rev 1.4).  This procedure issues the required remote command, instructing the UUT to execute a self-test.  It then immediately calls Sub Wait for OPC VISA (currently at Rev 1.2), which waits for the self-test to complete before proceeding, and also provides some error reporting capability.  The OPC sub appears to be utilizing its default timeout setting of 20 minutes (1200000 milliseconds) while waiting for the self-test to complete.

Option 1

Remove the automated self-test routine timer and replace it with a display prompt, instructing the operator to select "Advance" once the self-test finishes.  For maximum reliability, this is the fix that will be applied to the Gold procedures for self-tests and also signal path compensation routines.

To apply Option 1, replace existing steps 2.016 through 2.028 in "Sub Tek MDO/MSO/DPO Self-Test VISA" with something similar to the lines below.  This will cause MET/CAL to initiate the UUT self-test, pause briefly, and then display a prompt with operator instructions.  After the operator selects "Advance", MET/CAL will automatically query the UUT for the results of the self-test and proceed.
 2.028 WAIT [D2000] 2.029 DISP The UUT self-test is now in progress. 2.029 DISP 2.029 DISP Select "Advance" when it is complete.

Option 2

Allow a longer OPC timeout by adding the following line to "Sub Tek MDO/MSO/DPO Self-Test VISA".  Note that the timeout is specified in milliseconds.  This new line will override any timeouts set previously, and will also override the 20 minute default timeout setting within the OPC sub.  Increasing the timeout to one hour (3600000 ms) will allow a timeout of one hour.  However, if the UUT self-test completes in 10 minutes, the procedure will proceed and not make you wait the entire hour.  An exception to this could occur if there is an issue with the UUT that causes the self-test to hang: MET/CAL will then consume the entire hour while waiting for the operation to complete, unless you manually terminate the procedure.

To apply Option 2, add this MATH FSC statement immediately before the call to Sub Wait for OPC VISA:

 MATH @Timeout = 3600000 2.019 CALL Sub Wait for OPC VISA

Thank you for letting us know about this behavior, and please continue to let us know of any troubles that you encounter!

Chad Dodds
MET/CAL Procedure Development Manager
Fluke Calibration

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