Storing Data from Serial Connection

Hello All,
I am fairly new to LabView, I am trying to store and anaylze values from a non-Labview hardware via an rs-232 connection.
I have two devices on COM1 and COM2 ports. COM2 sends a value which I would like to store in an array. COM 2 points will form a somewhat sine wave within a few seconds. I would like to compare these values live to generate: max and min peak values, peak to peak values, and mean (I know LabView has signal icons for this, I'm just not sure how to wire it up).
I have attached the vi.
Thank you for your time and help.
Kelvin R.
Solved!
Go to Solution.
Attachments:
krreadwrite.vi ‏74 KB

kore101 wrote:I believe I need to use a for loop along with shift registers, but I just don't know how to.
LabVIEW Basics
LabVIEW 101
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Similar Messages

  • VISA Read gets incorrect data from serial connection

    I am having difficulty using the VISA functions in LabVIEW to read data from a virtual COM port. Data is being sent from a serial to USB chip via a USB connection using OpenSDA drivers. I have a python program written to read from this chip as well, and it never has an issue. However, when trying to achieve the same read in LabVIEW I am running into the problem of getting incorrect data in the read buffer using the VISA Read function.
    I have a VISA Configure Serial Port function set up with a control to select the COM port that the device is plugged into. Baud rate is default at 9600. Termination char of my data is a newline, which is also default. Enable termination char is set to true. A VISA Open function follows this configuration, and then feeds the VISA Resource Name Out into a while loop where a VISA Read function displays the data in read buffer. Byte count for the VISA Read is set to 20 so I can read more of the erroneous datat, however actual data will only be 6-12 bytes. The while loop has a wait function, and no matter how much I slow down the readings I still get incorrect data (I have tried 20ms thru 1000ms). 
    The data I expect to receive in the read buffer from VISA Read is in the form of "0-255,0-255,0-255\n", like the following:
    51,93,31\n
    or
    51,193,128\n
    And occasionally I receive this data correctly, however I intermittently (sometimes every couple reads, sometimes a couple times in a row) get incorrect readings like this:
    51,1\n
    51,193739\n
    \n
    51,1933,191\n
    51,,193,196\n
    51,1933,252 
    51,203,116203,186\n
    Where it seems like the read data is truncated, missing characters, or has additional characters. Looking at these values, however, it seems like the read was done incorrectly because the bytes seem partially correct (51 is the first number even in incorrect reads).
    I have search but haven't found a similar issue and I am not sure what to try from here on. Any help is appreciated. Thanks!
    Attachments:
    Serial_Read_debugging.vi ‏13 KB

    The first thing is that none of the error clusters are connected so you could be getting errors that you are not seeing. Are you sure about the comm parameters? Finally, I have never had a lot of luck looking for termination characters. You might want to just capture data and append each read into one long string just to see if you are still seeing this strangeness.
    What sort of device is returning the data? How often does it spit out the data? How much distance is there between it and your computer? Can you configure it append something like a checksum or crc to the data?
    Mike...
    Certified Professional Instructor
    Certified LabVIEW Architect
    LabVIEW Champion
    "... after all, He's not a tame lion..."
    Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

  • Read data from serial port or TCP port of frontend PC

    Hello Friends,
    I have requirement to read data from device connected to frontend PC which will provide meter reading data.
    Vendor has given me two option.
    1. Device can be connected to seiral port and data transfer will be done through MODBUS RTU protocol.In that case data need to capture from serial port.
    2. Device can be connected to TCP port and Socket program can be provided for data transfer. In that case SAP will act as client and communicate with TCP port.
    There will be multiple workstation with individual meters connected to them.
    I am aware of text file interfacing through front end tools using custom code using VB,JAVA or others.
    Is there any solution availble  to achieve above things using  ABAP other than text file , like direct communication?
    I am using ECC 6.0.

    Hello,
    Socket programming in not available on ABAP, but you may use RFC for the same.
    Use the below links for more details
    [Link 1|http://help.sap.com/printdocu/core/print46c/en/data/pdf/BCFESDE2/BCFESDE2.pdf]
    [Link 2|http://forums.sdn.sap.com/thread.jspa?threadID=1820233]
    Regards,
    Abhishek

  • Receive data from serial cable

    hello;
    i am building a program which recive data from serial port... and to tes it i constructed a circuit where i connect the pin 2 to a power source.
    c=inputStream.read();
         readBuffer.append( c);
         System.out.println("ok "+ readBuffer.toString() );
    the prevouse sentence is to print out the result, but the result is numbers ,0,10,255,16,8 collection of numbers at any time i connect the circuit.
    so can any one discuss to me what is these results?

    I agree with Dennis that the timing characteristics of the USB-6008
    would be insufficient to implement a serial interface with, but there
    are other issues as well which would prevent you from doing this.
    RS-232 has a maximum voltage of +/- 25V, which is higher than the
    limits of your device no matter how you connect it.  You may be
    able to read the incoming data line on the analog lines if you use
    differential mode (+/- 20V Range), but you would be unable to output
    any data.  The analog output range is 0-5V, so you wouldn't have
    any way to output the voltage levels needed for a RS-232 interface.
    Both the digital lines and the analog output are software timed, so you
    would not be able to produce the accurately timed I/O needed for a
    RS-232 interface.
    You could overcome the voltage issues by using a line converter such as
    a MAX232 chip to convert between RS-232 and TTL votlage levels, but you
    would still have timing issues which would make it difficult to produce
    a working serial interface.
    I would recommend that you look into purchasing a USB Serial interface.  National Instruments offers a full line of USB Serial Interfaces which allow you to easily interface with RS-232 devices on a computer without a serial port.

  • Unable to capture data from Serial port using LVRT2010 in single core pentium 4 machine

    I am using application written in Labview using windows Labview
    Runtime environment 2010. Application creates a tunnel to intercept data from
    Serial port.
    My problem is, Currently, I am using single core Pentium
    processor. When I am trying to intercept the data between COM1 and COM7 (COM 7
    is a virtual port) it is not able to capture data.
    When I am running Labview RT environment using dual core
    processor machine it is running normally. I wonder whether it could be the compatibility issues with
    single core Pentium processor.

    Hi Magnetica
    Are both of the machines running the same runtime engine,
    drivers ect?
    Have you had RT applications running on this
    machine before?
    Is the development computer a 64bit machine?
    The processor is a supported model (See link below).
    http://zone.ni.com/devzone/cda/tut/p/id/8239
    Regards
    Robert
    National Instruments UK & Ireland

  • How to save a datas from serial port?

    How to save a datas from serial port?

    Hi
    I need some help about rs-232 communication. I want to make a vi witch can do this things:
    -read a txt file (to simulate a serial port like when the datas are coming)
    i will get 3 different data in serial port (like this: 121 213 135)
    i want to save in a txt file what datas get my vi
    so
    -write in a txt file or draw in a diagram (or both)
    so my problem is: read in serial port and save in a file and draw a diagram.
    if anybody can help pls HELP ME because im a beginner in this problem.
    I already do something but Im not sure that good.
    Thx for all.

  • How to read data from a connected modem

    any one can help me? how to read data from a connected modem. The modem received real-time data from other server. The data is in text format. I can see this text when I used hyperterminal for dial up and the data is accumulated such as:
    @aa1235678
    @bb2135647
    @cc5214367
    since it is real-time data, I want to read one line each time instantly when it arrives.

    You need to use the Java Communications API. (http://java.sun.com/products/javacomm/index.html)

  • Regarding Short Dump While loading data from DB Connect

    Dear All,
    We are having an issue of getting short dump while loading data from DB Connect to BW. We were able to load the data into BW Dev using the same data source without any problem. Whereas in Production, I am getting the following error:
    Runtime Error          PERFORM_CONFLICT_TAB_TYPE  
    Except.                   CX_SY_DYN_CALL_ILLEGAL_TYPE
    What could be the reason for the error that I am getting

    hi,
    Refer Note 707986 - Writing in trans. InfoCubes: PERFORM_CONFLICT_TAB_TYPE
    Summary
    Symptom
    When data is written to a transactional InfoCube, the termination PERFORM_CONFLICT_TAB_TYPE occurs. The short dump lists the following reasons for the termination:
    ("X") The row types of the two tables are incompatible.
    ("X") The table keys of the two tables do not correspond.
    Other terms
    transactional InfoCube, SEM, BPS, BPS0, APO
    Reason and Prerequisites
    The error is caused by an intensified type check in the ABAP runtime environment.
    Solution
    Workaround for BW 3.0B (SP16-19), BW 3.1 (SP10-13)
    Apply the attached correction instructions.
    BW 3.0B
    Import Support Package 20 for 3.0B (BW3.0B Patch20 or SAPKW30B20) into your BW system. The Support Package is available oncenote 0647752 with the short text "SAPBWNews BW3.0B Support Package 20", which describes this Support Package in more detail, has been released for customers.
    BW 3.10 Content
    Import Support Package 14 for 3.10 (BW3. 10 Patch14 or SAPKW31014) into your BW system. The Support Package is available once note 0601051 with the short text "SAPBWNews BW 3.1 Content Support Package 14" has been released for customers.
    BW3.50
    Import Support Package 03 for 3.5 (BW3.50 Patch03 or SAPKW35003) into your BW system. The Support Package is available once note 0693363 with the short text "SAPBWNews BW 3.5 Support Package 03", which describes this Support Package in more detail, has been released for customers.
    The notes specified may already be available to provide advance information before the Support Package is released. However, in this case, the short text still contains the term "Preliminary version" in this case.
    Header Data
    Release Status: Released for Customer
    Released on: 18.02.2004 08:11:39
    Priority: Correction with medium priority
    Category: Program error
    Primary Component: BW-BEX-OT-DBIF Interface to Database
    Secondary Components: FIN-SEM-BPS Business Planning and Simulation
    Releases
    Software
    Component Release From
    Release To
    Release And
    subsequent
    SAP_BW 30 30B 30B
    SAP_BW 310 310 310
    SAP_BW 35 350 350
    Support Packages
    Support
    Packages Release Package
    Name
    SAP_BW_VIRTUAL_COMP 30B SAPK-30B20INVCBWTECH
    Related Notes
    693363 - SAPBWNews BW SP03 NW'04 Stack 03 RIN
    647752 - SAPBWNews BW 3.0B Support Package 20
    601051 - SAPBWNews BW 3.1 Content Support Package 14
    Corrections Instructions
    Correction
    Instruction Valid
    from Valid
    to Software
    Component Ref.
    Correction Last
    Modifcation
    301776 30B 350 SAP_BW J19K013852 18.02.2004 08:03:33
    Attributes
    Attribute Value
    weitere Komponenten 0000031199
    Thanks
    (Activate ODS/Cube and Transfer rules again..)

  • Pick Data From Serial/USB ports

    How can I pick Data from Serial/USB ports Machines
    I want to put Results into Database from Haematology Machine

    You will have to write a Java program to do this and then use a Java Pluggin Commponent (JPC) to read the data into Forms.
    Look on the Internet for code showing how to work with USB ports, and see Francois web site about PJCs.
    http://sheikyerbouti.developpez.com/index_en/

  • I use LabVIEW 7.1 but I have some problem when, I use LabVEW to read the data from serial communication

    I use LabVIEW 7.1 but I have some problem when, I use LabVEW to read the data from serial communication.
    I use LabVIEW to read the data from serial communication then, i open the example (.vi) from Serial Communication - Advanced Serial Write and Read  from LabVIEW Example. BUT it have some error message that : Error - 1073807202 occured  at property node in visa configure serial port (instr).vi -> advance serial write and read .vi
    this error code is undefined. no one has provide a description for this code, or you might have wired a number that is not an error code to the error code input.
    I don't know why? please help me. thank you.

    When I copy that code into "Explain Error" I get: "VISA:  (Hex 0xBFFF009E) A code library required by VISA could not be located or loaded."
    You may have a bad install of VISA or the wrong version of VISA loaded. Try re-installing VISA. You can get the latest version from the NI support site: http://digital.ni.com/softlib.nsf/webcategories/85256410006C055586256BBB002C0E91?opendocument&node=1....
    Also ensure that you are not pointing the example towards a serial port that does not exist.
    Please let us know what you find and what gets this working for you.
         Rob

  • Problem while reading data from Serial Port

    Hi All,
    I am facing some problem while reading data from Serial Port.
    As per the requirement I am writing the data on Serial Port and waiting for response of that data.
    Notification for data availabilty is checked with method public void serialEvent(SerialPortEvent event) of javax.comm.SerialPortEventListener.
    When we are writing data on the port one thread i.e. "main" thread is generated and when data availability event occures another thread "Win32SerialPort Notification thread" is generated. This creates problem for me as we can't control thread processing.
    So can anybody pls explain me how to overcome this problem?
    Regards,
    Neha

    My Problem is:-
    I am simoultaneouly wrting data on port & reading data from port.
    First I write data on port using outputStream.write() method. Now when target side sends me response back for the request on serial port DATA_AVAILABLE of SerialPortEventListner event occured,we are reading data from serial port.Now till the time we didn't get the response from target next command can't be written on the serial port. When we are writing data on port main thread is executed.Now my problem starts when DATA_AVAILABLE event occured.At this point another thread is created.Due to this my program writes data of next command without reading response of previous command.To solve this prob. I have used wait() & notify() methods as follows.But again due to this my pc hangs after execution of 2 commands. (PC hang in while loop in a code provided below.)
    From SOPs I could figure it out that after 2 commands we are not able to write data on serial port so DATA_AVAILABLE event doesn't occure n pro. goes in wait state.
    Can anybody help me to solve this issue.
    Neha.
    Code:
    public void serialEvent(SerialPortEvent event)
              switch (event.getEventType())
                   case SerialPortEvent.BI:
                   case SerialPortEvent.OE:
                   case SerialPortEvent.FE:
                   case SerialPortEvent.PE:
                   case SerialPortEvent.CD:
                   case SerialPortEvent.CTS:
                   case SerialPortEvent.DSR:
                   case SerialPortEvent.RI:
                   case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
                                 break;
                   case SerialPortEvent.DATA_AVAILABLE:
                        try
                             dataThread = Thread.currentThread();
                             dataThread.setPriority(10);
                             dataAvailable = true;
                                                                                    byte[] tempArray=new byte[availableBytes];
                                        inputStream.read(tempArray);
                                                                       catch (IOException io)
                             SOP(io, "Error in serialEvent callback call for event DATA_AVAILABLE");
    public void  writetoPort(byte[] data) throws IOException
                             outputStream.write(data);
                              while(finalTimeOut >= actualTime)
                            if( ! dataAvailable)
                                    actualTime = System.currentTimeMillis();
                           else
              synchronized (mainThread)
                   mainThread = Thread.currentThread();
                   mainThread.wait();
    public  void sendDatatoUser(byte[] b) throws Exception, HWCCSystemFailure
              obj.returnData(b);
              synchronized(mainThread)
                   mainThread.notify();
                                                           

  • To read & save data from serial port (write to .csv file), and plot data as waveform

    Hi,
    I've been stuck with this problem for weeks and really need some help. I've been searching a lot but I can't find a proper solution.
    I am trying to use Labview to plot and display some parameters of a data acquisition system for a project.
    The data acquisition system is connected to a computer via serial connection through COM 1 port.
    The data acquisition system sends a serial stream of data (ASCII string with baud rate 19200), as shown below (from HyperTerminal),
    01:00:26,933.24,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    01:00:27,931.54,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    The serial data stream consists of a time stamp (as 1st data), followed by 16 individual channel data, separated by comma "," and each stream ending in return "\n". Each value of the data ranges from 1 to 6 digits (value of -5000 to 15000).
     I have no problem reading this values correctly using HyperTerminal, but I have problem to plot and display individual parameters of this serial string in Labview. I want to save the entire data in  a “.csv” file corresponding to all the 16 channels with time stamp and plot each individual channel parameter in a graph with time on X-axis.
    I am relatively new to Labview hope I can learn a lot from your help.
    　Thank you

    Thank you Dennis.........
    Now I had modified the program incorporating1D array for gauge display.....but currently I have a new problem. The program is running updating the file, waveform graph and Gauge very slowly. Approximately once in every 15 seconds 16 data streams are getting updated in a bunch with gauge sticking to the last value rather than indicating real time value.
    eg.
    12:33:41,-3728.78,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:42,-3730.47,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:43,-3729.81,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:44,-3733.80,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:45,-3733.57,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:46,-3729.27,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:47,-3725.97,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:48,-3730.14,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:49,-3733.20,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:50,-3733.60,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:51,-3732.24,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:52,-3734.51,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:53,-3728.07,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:54,-3732.54,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:55,-3732.24,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    12:33:56,-3731.58,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.00,
    gets updated in a bunch after 15 seconds, rather than in every second. I thought the problem is with while loop but, i realised there is no delay associated with it..... Can u kindly help me in modifing the program so as it can update the waveform, file data and gauge in real time? (I have attached the modified VI file "suitcase new.vi" and the data gathered after executing the same as in "Trail.txt".)
    Thank You,
    Rahul
    Attachments:
    trail.txt ‏85 KB
    suitcase new.vi ‏44 KB

  • Adobe Reader is Cacheing Data From OLEDB Connection

    I am trying to pre-populate a form from an oledb connection to an access database. I have an html page where a user can search an id. This id then gets written to a table where the sql query defined in the PDF form can grab it, join it with a table where the user info is stored, then display it.
    My problem is that Adobe Reader seems to be caching data from the first SQL select query that is executed. When I change the id I am loading, I still get data from the first SQL query in Reader. If I open the PDF via Acrobat, the data loads up properly, and it doesn't seem to be cached. I have looked at the following forum for suggestions: http://www.adobeforums.com/webx/.3bc3549c, but their suggestions haven't worked.
    I have tried turning off caching anywhere I can find it (i.e. in LiveCycle, Adobe Reader), but nothing is working. Does anybody have any suggestions?

    It sounds like you need use the adobe schema in MII so the output of your transaction matches it.
    Regards,
    Jamie

  • How to get data from serial port to GUI textArea

    From Serial Port.....
    Messages from base (always 5 bytes):
    0xAA, 0, 0, 0, 0xBB - IDLE Mode
    0xAA, 0, 0x80, 0x80, 0xBB - Question Mode
    messages from terminal (always 6 bytes):
    0xAA, a, b, c, chksum, 0xBB
    where chksum = a+b+c;
    a = address (0-250)
    the 2 MSB's of b represenet the answer:
    0 0 - A
    0 1 - B
    1 0 - C
    1 1 - D
    the 6LSB's of b and 8bits of c is the time for answer, in milliseconds.
    (0-16384 milliseconds)
    I have VB Code for that but I want the same thing in Java ...
    Can any one help me?
    Here's VB Code..
    VERSION 5.00
    Object = "{648A5603-2C6E-101B-82B6-000000000014}#1.1#0"; "MSCOMM32.OCX"
    Begin VB.Form Form1
       BorderStyle     =   1  'Fixed Single
       Caption         =   "Aakar GUI"
       ClientHeight    =   4665
       ClientLeft      =   60
       ClientTop       =   375
       ClientWidth     =   6105
       LinkTopic       =   "Form1"
       MaxButton       =   0   'False
       MinButton       =   0   'False
       ScaleHeight     =   311
       ScaleMode       =   3  'Pixel
       ScaleWidth      =   407
       StartUpPosition =   3  'Windows Default
       Begin VB.CommandButton cmdPort
          Caption         =   "Open Port"
          Height          =   375
          Left            =   120
          TabIndex        =   4
          Top             =   600
          Width           =   1455
       End
       Begin VB.ComboBox cmbPort
          Height          =   315
          ItemData        =   "Form1.frx":0000
          Left            =   120
          List            =   "Form1.frx":0016
          Style           =   2  'Dropdown List
          TabIndex        =   3
          Top             =   120
          Width           =   2895
       End
       Begin VB.CommandButton cmdEnd
          Caption         =   "End"
          Height          =   495
          Left            =   1560
          TabIndex        =   2
          Top             =   1320
          Width           =   1215
       End
       Begin VB.CommandButton cmdStart
          Caption         =   "Start"
          Height          =   495
          Left            =   120
          TabIndex        =   1
          Top             =   1320
          Width           =   1215
       End
       Begin VB.TextBox txtMessage
          Height          =   2040
          Left            =   119
          MultiLine       =   -1  'True
          ScrollBars      =   3  'Both
          TabIndex        =   0
          Top             =   2475
          Width           =   5848
       End
       Begin VB.Timer tmrRead
          Enabled         =   0   'False
          Interval        =   1
          Left            =   2040
          Top             =   600
       End
       Begin MSCommLib.MSComm MSComm1
          Left            =   3120
          Top             =   360
          _ExtentX        =   1164
          _ExtentY        =   1164
          _Version        =   393216
          DTREnable       =   0   'False
          ParityReplace   =   45
          SThreshold      =   1
       End
       Begin VB.Label Label5
          Caption         =   "Result Data:"
          Height          =   375
          Left            =   120
          TabIndex        =   5
          Top             =   2115
          Width           =   1320
       End
    End
    Attribute VB_Name = "Form1"
    Attribute VB_GlobalNameSpace = False
    Attribute VB_Creatable = False
    Attribute VB_PredeclaredId = True
    Attribute VB_Exposed = False
    Option Explicit
    Dim PortIsOpen As Boolean
    Dim Answers(4) As String
    Dim RejectKeystroke As Boolean
    Private Sub cmbPort_Change()
    Debug.Print cmbPort.ListIndex
    End Sub
    Private Sub cmbPort_Validate(Cancel As Boolean)
    'Cancel = True
    End Sub
    Private Sub cmdEnd_Click()
    MSComm1.Output = "e"
    txtMessage.Text = ""
    End Sub
    Private Sub cmdPort_Click()
    On Error GoTo ErrorHandler
    If cmbPort.ListIndex < 0 Then Exit Sub
    If PortIsOpen Then
        cmbPort.Enabled = True
        MSComm1.PortOpen = False
        PortIsOpen = False
        cmdPort.Caption = "Open Port"
        cmdStart.Enabled = False
        cmdEnd.Enabled = False
    Else
        MSComm1.CommPort = cmbPort.ListIndex + 1
        cmbPort.Enabled = False
        MSComm1.PortOpen = True
        PortIsOpen = True
        cmdPort.Caption = "Close Port"
        cmdStart.Enabled = True
        cmdEnd.Enabled = True
    End If
    Exit Sub
    ErrorHandler:
    Debug.Print Err.Number
    Debug.Print Err.Description
    MsgBox Err.Description, vbExclamation Or vbOKOnly, "Error opening port"
    cmbPort.Enabled = True
    PortIsOpen = False
    cmdPort.Caption = "Open Port"
    cmdStart.Enabled = False
    cmdEnd.Enabled = False
    End Sub
    Private Sub cmdStart_Click()
    MSComm1.Output = "s"
    txtMessage.Text = ""
    End Sub
    Private Sub Form_Initialize()
    Dim tmp As Variant
    tmp = InitCommonControls
    End Sub
    Private Sub Form_Load()
    Answers(0) = "A"
    Answers(1) = "B"
    Answers(2) = "C"
    Answers(3) = "D"
    'MSComm1.Settings = "9600,n,8,1"
    ''MSComm1.Settings = "115200,n,8,1"
    'MSComm1.PortOpen = True
    On Error GoTo ErrorHandler1
    MSComm1.CommPort = 1                    ' comm port 1
    MSComm1.RThreshold = 1                  ' use 'on comm' event processing
    MSComm1.Settings = "9600,n,8,1"         ' baud, parity, data bits, stop bits
    MSComm1.SThreshold = 1                  ' allows us to track Tx LED
    MSComm1.InputMode = comInputModeText    'comInputModeBinary  ' binary mode, you can also use
                                            ' comInputModeText for text only use
    PortIsOpen = False
    cmbPort.ListIndex = 0
    ' open the port
    MSComm1.PortOpen = True
    cmbPort.Enabled = False
    PortIsOpen = True
    cmdPort.Caption = "Close Port"
    cmdStart.Enabled = True
    cmdEnd.Enabled = True
    Exit Sub
    ErrorHandler1:
    Debug.Print Err.Description
    PortIsOpen = False
    cmbPort.Enabled = True
    cmdPort.Caption = "Open Port"
    cmdStart.Enabled = False
    cmdEnd.Enabled = False
    End Sub
    Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
    If MSComm1.PortOpen Then MSComm1.PortOpen = False
    End Sub
    Private Sub lblOption_Click()
    End Sub
    Private Sub MSComm1_OnComm()
    ' Synopsis:     Handle incoming characters, 'On Comm' Event
    ' Description:  By setting MSComm1.RThreshold = 1, this event will fire for
    '               each character that arrives in the comm controls input buffer.
    '               Set MSComm1.RThreshold = 0 if you want to poll the control
    '               yourself, either via a TImer or within program execution loop.
    '               In most cases, OnComm Event processing shown here is the prefered
    '               method of processing incoming characters.
        Dim i As Long
        Dim sBuff    As String           ' buffer for holding incoming characters
        Const MTC       As String = vbCrLf  ' message terminator characters (ususally vbCrLf)
        Const LenMTC    As Long = 2         ' number of terminator characters, must match MTC
        Dim iPtr        As Long             ' pointer to terminatior character
        ' OnComm fires for multiple Events
        ' so get the Event ID & process
        Select Case MSComm1.CommEvent
            ' Received RThreshold # of chars, in our case 1.
            Case comEvReceive
                ' read all of the characters from the input buffer
                ' StrConv() is required when using MSComm in binary mode,
                ' if you set MSComm1.InputMode = comInputModeText, it's not required
                'sBuff = sBuff & StrConv(MSComm1.Input, vbUnicode)
                'If Len(txtMessage.Text) > 4096 Then txtMessage.Text = ""
                sBuff = MSComm1.Input
                Dim ch As String
                Dim PacketStart As Boolean
                Dim PacketLength As Integer
                Dim Packet() As String
                PacketStart = False
                PacketLength = 0
                While (Len(sBuff) > 0)
                    ch = Left(sBuff, 1)
                    If (ch = Chr(&HAA)) Then PacketStart = True
                    If (ch = Chr(&HBB)) Then PacketStart = False
                    If (ch <> Chr(&HAA) And ch <> Chr(&HBB)) Then
                        PacketLength = PacketLength + 1
                        ReDim Preserve Packet(PacketLength)
                        Packet(PacketLength) = ch
                    End If
                    'txtMessage.Text = txtMessage.Text + Format(Hex(Asc(ch)), " @@")
                    sBuff = Right(sBuff, Len(sBuff) - 1)
                Wend
                If (PacketLength = 3) Then
                    Debug.Print "Command packet recieved"
                    'txtMessage.Text = txtMessage.Text + vbCrLf + "Address =" + Str(Asc(Packet(1)))
                    'txtMessage.Text = txtMessage.Text + vbCrLf + "Address =" + Str(Asc(Packet(2)))
                End If
                If (PacketLength = 4) Then
                    Debug.Print "Response packet recieved"
                    txtMessage.Text = txtMessage.Text + "Address =" + Str(Asc(Packet(1))) + _
                        " Answer = " + Answers((Asc(Packet(2)) And &HC0) / 64) + _
                        " Time =" + Str((Asc(Packet(2)) And &H3F) * 256 + (Asc(Packet(3)))) + "mS" + vbCrLf
                    'txtMessage.Text = txtMessage.Text + vbCrLf + "Address =" + Str(Asc(Packet(1)))
                    'txtMessage.Text = txtMessage.Text + vbCrLf + "Option =" + Str((Asc(Packet(2)) And &HC0) / 64)
                    'txtMessage.Text = txtMessage.Text + vbCrLf + "Time =" + Str((Asc(Packet(2)) And &H3F) * 256 + (Asc(Packet(3))))
                End If
                If (PacketLength <> 4 And PacketLength <> 3) Then Debug.Print "Unknown packet of length" + Str(PacketLength) + " recieved"
                txtMessage.Text = txtMessage.Text + vbCrLf
            ' An EOF charater was found in the input stream
            Case comEvEOF
                DoEvents
            ' There are SThreshold number of characters in the transmit  buffer.
            Case comEvSend
                DoEvents
            ' A Break was received.
            Case comEventBreak
                DoEvents
            ' Framing Error
            Case comEventFrame
                DoEvents
            ' Data Lost.
            Case comEventOverrun
                DoEvents
            ' Receive buffer overflow.
            Case comEventRxOver
                DoEvents
            ' Parity Error.
            Case comEventRxParity
                DoEvents
            ' Transmit buffer full.
            Case comEventTxFull
            ' Unexpected error retrieving DCB]
            Case comEventDCB
                DoEvents
        End Select
    End Sub
    Private Sub tmrRead_Timer()
    'MSComm1.Output = vbCrLf + vbCrLf
    'MSComm1.Output = Chr(128)
    End Sub
    Private Sub txtMessage_KeyDown(KeyCode As Integer, Shift As Integer)
    If Shift = 2 Or Shift = 4 Then RejectKeystroke = False Else RejectKeystroke = True
    End Sub
    Private Sub txtMessage_KeyPress(KeyAscii As Integer)
    If RejectKeystroke Then
        KeyAscii = 0
    End If
    End SubThanks in advance..

    I want to replicate the entire VB program as Java Program.
    This has to be included in my project which i am doing in java.

  • Problem in reading data from serial port continuously- application hangs after sometimes

    I need to read data from two COM port and order of data appearance from COM port is not fixed. 
    I have used small timeout and reading data in while loop continously . If my application is steady for sometime it gets hangs and afterwards it doesnt receive any data again. 
    Then I need to restart my application again to make it work.
    I am attaching VI. Let me know any issue.
    Kudos are always welcome if you got solution to some extent.
    I need my difficulties because they are necessary to enjoy my success.
    --Ranjeet
    Attachments:
    Scanning.vi ‏39 KB

    billko wrote:
    Ranjeet_Singh wrote:
    I need to read data from two COM port and order of data appearance from COM port is not fixed. 
    I have used small timeout and reading data in while loop continously . If my application is steady for sometime it gets hangs and afterwards it doesnt receive any data again. 
    Then I need to restart my application again to make it work.
    I am attaching VI. Let me know any issue.
    What do you mean, "not fixed?"  If there is no termination character, no start/stop character(s) or even a consistent data length, then how can you really be sure when the data starts and stops?
    I probably misunderstood you though.  Assuming the last case is not ture - there is a certain length to the data - then you should use the bytes at port, like in the otherwise disastrous serial port read example.  In this case, it's NOT disastrous.  You have to make sure that you read all the data that came through.  Right now you have no idea how much data you just read.  Also, if this is streaming data, you might want to break it out into a producer/consumer design pattern.
    Not fixed means order is not fixed, data from any com port can come anytime. lenght is fixed, one com port have 14 byte and other 8 byte fixed..
    Reading data is not an issue for me as it works nice but I have a query that why my application hangs after sometime and stops reading data from COM PORT.
    Kudos are always welcome if you got solution to some extent.
    I need my difficulties because they are necessary to enjoy my success.
    --Ranjeet

Maybe you are looking for