A breakpoint problem (step into and step over makes differences)

[bhl3302]

Hi crossrulz, I have a question here regarding race condition. If there indeed have a race condiction in this block, how did you figure out this one is from "visa resource"? Is there any other ones caused this race condition? Thank you!

[crossrulz]

It is all about data dependency.  If there is no data dependency between the VISA Clear and the VISA Write, then it is very possible that you are clearing the buffer after the data has been recieved, cleared, and then read.  The best way to make sure the Clear happens first is to wire the VISA Resource and the Error cluster from the VISA Clear to the VISA Write.

But thinking about this again, I am wrong.  The Diagram Disable Structure has to complete first.  So that is not a race condition.

[Ben]

After letting cross do all of the dirty work...

Could it be a timing issue and the operation is timing out but in lightbulb mode it has more time?

Ben

[bhl3302]

Hi Ben, if there is a timing issue, where do you think can cause it? Because I do not see any time related items there, could you give me more deatil? Thank you!

[Ben]

the widget you are talking to may need more time to reply.

Ben

[bhl3302]

Hi Ben, if it needs more time to reply, what should I do? Thank you very much!

[bhl3302]

Hi Ben, if it needs more time to reply, what should I do? Thank you very much!

[Mark_Yedinak]

You could use a simple state machine. The other simple way is to insert a delay between your actions. If you are waiting for responses you can also increase your read timeout.

[Ben]

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@bhl3302 wrote:

Hi Ben, if it needs more time to reply, what should I do? Thank you very much!

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THat question is probably best answered by the maker of the widget.

THey may have a "status" flag that can be checked to see if it is done or the widget just needs more time where a small dealy can be introduced (ms wait function) or simply retry the operation until it responds.

But I am speculating.

You should drop probes or indicators on all of the wires of interest to get a clue of the nature of the failure. Quoting myself "The first step in solving a problem is clearly defing what the problem is."

Ben

[Kevin_Price]

Ben,

Re: your quote.  I guess great minds think alike.  I've heard a similar saying quoted as though it were a well-known (but unattributed) aphorism, "A problem well-defined is a problem half-solved."

-Kevin P