DQMH Consortium Toolkits Discussions
Helper loop error catching
Solved!
Hi All,
I just tried out the new helper loop feature in DQMH 7 - very useful. I have couple questions related to the architecture, hope someone can clarify.
1. The unregister for event error out or the error handler error out - I expected them to be merged to the main error out as shown below. What's the reason behind not linking them?
2. I just did a simple case to generate a error within the timeout case and gave the error code 5 & description Test. The tester displayed an unrelated error description as highlighted below. Am I not using the error handling within helper loop properly?
3. Can I have more than one helper loop in a module? e.g. one for reading FPGA values periodically, another reading OPC-UA commands from an instrument periodically.
Hey Asa77, thanks for test-driving 7.0!
Re. 1: If you look at the block diagram of the DQMH Error Handler VI for the helper loop, you'll see that the returned error is merely a duplicate of the error coming in. In the case of an error, it is sent to the Error case of the MHL from within that VI. Seeing as the error is processed, we don't need to handle it outside the VI or the helper loop.
For the event registration, seeing as it consumes the same cluster of event references as the EHL, it's highly unlikely that there would be an error for the helper loop but not for the EHL (where we handle the error). That being said, if you wire additional events to the registration node, you should consider also wiring the error out terminals.
Re. 2: LabVIEW comes with lots of predefined error codes. The definition for error code 5 is "File already open". If you go to Help -> Explain Error..., you'll see the same string that DQMH shows in the error description.
Re. 3: Yes, you can create as many helper loops for a module as you wish. You'll be pleased to hear that when adding requests, you can actually choose which loop it should be registered for.
Hope that helps!
