課件成果ni培訓(xùn)lesson error handling

1、Lesson 4 Error HandlingImportance of Error HandlingDetect and Report ErrorsErrors and WarningsRanges of Error CodesError HandlersA. Importance of Error HandlingEssential for:Debugging: Helps to catch programming errorsStress testing: Helps to test application boundary casesRobustness: Helps detect e

2、rrors introduced by system and environment differences Error Handling Anticipation, detection, and resolution of warnings and errorsB. Detect and Report ErrorsPropagate errors along wiresMerge errors from different wire pathsMerge Error VIMerge Error VI returns the first error found. If no error is

3、found, it returns the first warning.This VI does not concatenate errors.C. Errors and WarningsErrorStatus = TrueWarningStatus = False and Code is nonzeroErrors and WarningsReport errors and warnings with the Simple Error Handler VIModify Type of Dialog to detect warningsCall the Simple Error Handler

4、 VI from the top-level VIAvoid error dialogs in subVIsErrors and WarningsUse shift-registers to detect errors and warnings in all loop iterationsUse error status as a condition to stop a loopWhile LoopsConditional For LoopsD. Ranges of Error CodesRefer to the LabVIEW Help for complete list of error

5、code ranges:FundamentalsRunning and Debugging VIsHow-ToError Codes and MessagesRanges of LabVIEW Error CodesCodes are subdivided into ranges according to product and VI groupingMost codes are unique, but some error codes are used by more than one product or VI groupingE. Error HandlersExamples:Simpl

6、e Error Handler VI Optionally display a dialog box with error information when an error occurs.State machine error handler Transitions the state machine to an error or shutdown state when an error occurs.I/O error handler If an I/O operation times out, retry for a certain period of time before repor

7、ting an error.Error Handler A VI or code that changes normal flow of program execution when an error occurs.Exercise 4-1Updating the Print Console With Error HandlingUpdate a VI to report errors and include a shutdown state.Exercise 4-1Updating the Print Console With Error HandlingWhat will happen i

8、f there is an error in the consumer loop but not the producer loop? How can you fix this?SummaryQuizMerge Errors VI concatenates error information from multiple sources.TrueFalse12SummaryQuiz AnswerMerge Errors VI concatenates error information from multiple sources.TrueFalse13SummaryQuizAll errors have negative error codes and all warnings have positive err