Error 4 Occurred At Read From Text File
document has been archived and is no longer updated by National Instruments Hardware: PXI/CompactPCI>>Controllers Problem: I have a file that I am reading using the Read File VI in LabVIEW. It reads all the contents of the file correctly, but then gives me the following message Error 4 Occurred at Read File in XXX.vi. Possible Reasons: End of File when it gets to the end of the file. I even get the same error when I use the Read From Text File VI example from National Instruments. How can I prevent this error? Solution: The information in this article pertains to older versions of LabVIEW, the Read From Text File VI was rewritten completely and this information does not apply to later versions of LabVIEW.This is expected behavior when the end of the file is read. The Read From Text File VI example is designed so that the While Loop that reads the file will terminate if the user presses the stop button or if an error occurs. Then it simply displays the error in a pop-up dialog box. Even though Error 4 shows up as an error, it is not fatal; it simply informs the user that the end of the file has been reached. By handling the error appropriately you can prevent the error from showing up. The following are some ways you can prevent this error from displaying: You can omit or disconnect the Simple Error Handler VI or General Error Handler VI completely. But then, if you have other errors besides the one above, you will not be able to see those in a pop-up dialog box either. Set the Type of Dialog node of the error handler VI to 0 (zero). This will disable a pop-up dialog box. In this case also, you will not be able to see other errors. If you know how many lines your file has, use a For Loop and set it to iterate and read that number of times from the file. If the number of lines in your file changes or for a more dynamic solution, change your code to expect Error 4 and handle it accordingly. Use the Unbundle by Name node to extract the error code. If the code is equal to 4, then change the error status from TRUE to FALSE. Then bundle the error cluster using Bundle by Name node. Setting the error status to FALSE will instruct the error handler to ignore the error. But it will still display other errors in a pop-up dialog box. Refer to Read From
Custom Icon in Application Builder Primary Software: LabVIEW Development Systems>>LabVIEW Professional Development System Primary Software Version: 7.1 Primary Software Fixed Version: N/A Secondary Software: N/A Problem: I am encountering Error 4 after selecting my custom icon in LabVIEW Application Builder. In LabVIEW 7.x the error message is:Error 4 occurred at Read File in Read BMP Data.vi->Read Icons from ICO File.vi->Read Icons http://digital.ni.com/public.nsf/allkb/A1DA28A91A4680A786256D050065F294 for Application.vi->Dist Call Get Icons.vi->Build Application.viIn LabVIEW 8.x and later the error message is:Error 4 occurred at Read from Binary File in Read BMP Data.vi->Read Icons from ICO File.vi->Read Icons for Application.vi->ABAPI Dist Call Get Icons.vi->EBUIP_Get_Icons.vi->EBUIP_Build_Rule_Editor.vi->EBUIP_Item_OnDoProperties.vi->EBUIP_Item_OnDoProperties.vi.ProxyCallerWhat can I do to resolve this error? Solution: This error occurs when an .ico http://digital.ni.com/public.nsf/allkb/ABDB91CDA0837D4286256F3500011AFF file has one or more icons saved with color pallets that are True Colors (24-bit color). To avoid this error and to allow your application to build successfully, it is necessary to edit the .ico file and ensure that all icons are saved with a color pallet other than True Color (24-bit color). Using the icon editor in Application Builder to create a 16 color 32x32 icon will never encounter this problem. Related Links: KnowledgeBase 18SGJ9VJ: Customizing an Icon for a Executable Created in LabVIEW Attachments: Report Date: 10/21/2004 Last Updated: 07/23/2014 Document ID: 3EKI61T0 Your Feedback! Poor|Excellent Yes No Document Quality? Answered Your Question? 1 2 3 4 5 Document needs work? Please tell us why. Please Contact NI for all product and support inquiries. My Profile | RSS | Privacy | Legal | Contact NI © 2014 National Instruments Corporation. All rights reserved. |
TestStand Primary Software: Primary Software Version: 3.5 Primary Software Fixed Version: 3.5 Secondary Software: N/A Problem: I am using the "Read From Measurement File" http://digital.ni.com/public.nsf/allkb/4D9AAFF41DC004D286257126000B3D6C Express VI in one of my TestStand sequences to read in a file. I have one LabVIEW action step that is configured to use the Express VI. The sequence runs http://www.cs.mtu.edu/~shene/COURSES/cs201/NOTES/chap04/iostatus.html correctly the first time through, but displays error code 4 as shown below in future runs. This error occurs both with the LabVIEW Development System or the LabVIEW Run-time Engine error 4 selected as the LabVIEW Server in the Adapter options. I don't receive this error when I repeatedly run the Express VI in LabVIEW. Solution: The error from the Express VI is expected as the Express VI contains flags that prevent it from reading the same file once it hits the end of the file flag. LabVIEW resets these flags every time error 4 occurred the VI is run. However,in TestStand, by default, VIs are reserved for execution meaning the flags retain their current values and are not reset. This causes error code 4 to appear. Two possible workarounds are as follows. Option 1: Specify that LabVIEW does not reserve each VI when TestStand loads the VI. Launch either the TestStand Sequence Editor or a TestStand Operator Interface. Select Configure » Adapters.... Select the LabVIEW adapter and press the Configure... button. Uncheck the Reserve Loaded VIs for Execution option and click OK. Option 2: Specify that each code module is unloaded after step execution.* Launch the TestStand Sequence Editor. Select Edit » Sequence File Properties. Under the Unload Option drop down menu, select Unload after Step Executes and then click OK. *It is unnecessary to unload all code modules for all steps to prevent this error. Instead, you can specify that each step calling the express VI unload its code module individually. Launch the TestStand Sequence Editor. Right click the individual step and select Properties. Select the Run Options tab and under the Unloa
fact, you have encountered such a technique in Programming Assignment 1 in which a keyword IOSTAT= was used in a READ statement. The following is its syntax: INTEGER :: IOstatus READ(*,*,IOSTAT=IOstatus) var1, var2, ..., varn The third component of the above READ is IOSTAT= followed by an INTEGER variable. The meaning of this new form of READ is simple: After executing the above READ statement, the Fortran compiler will put an integer value into the integer variable following IOSTAT=, IOstatus above. Based on the value of IOstatus, we have three different situations: If the value of IOstatus is zero, the previous READ was executed flawlessly and all variables have received their input values. This is the normal case. If the value of IOstatus is positive, the previous READ has encountered some problem. In general, without knowing the system dependent information, it is impossible to determine what the problem was. However, if hardware and I/O devices are working, a commonly seen problem would be illegal data. For example, supplying a real number to an integer variable. If IOstatus is positive, you cannot trust the values of the variables in the READ statement; they could all contain garbage values, or some of them are fine while the others are garbage. If the value of IOstatus is negative, it means the end of the input has reached. Under this circumstance, some or all of the variables in the READ may not receive input values. What is the end of file? How do we generate it? If you prepare your input using a file, when you save it, the system will generate a special mark, called end-of-file mark, at the end of that file. Therefore, when you read the file and encounter that special end-of-file mark, the system would know there is no input data after this mark. If you try to read passing this mark, it is considered as an error. If you prepare the input using keyboard, hiting the Ctrl-D key would generate the end-of-mark under UNIX. Once you hit Ctrl-D, the system would consider your input stop at there. If your program tries to read passing this point, this is an error. However, with IOSTAT=, you can catch this end-of-file mark and do something about it. A commonly seen application is that let the program to count the number of data items as will be shown in examples below. Examples In the following code, the DO-