How to configure visa to adquire dat from serial port and then converted to numeric value from a home embedded device
I already stablish communication with my serial port using VISA, selecting COM1 as the resoure name.
After that, I tried to read the data from the port (as we know the data was in string format )but I need to convert the data to numeric value to hadle it (no arrays).
Another main thing is that I'm develoing a new based Embedded design and tthe info that will trhow out from the device to the PC is binary.
How can I solved the problem, and if I want to make bidirectional communication with my system how can I do it? The VISA intructions as *IDN? and so forthetc can be recognize by the external system if the COM1 port is recognized by NI Max as ADSRL1::I
NSTR1?
Hello,
For an example of bidirectional serial communication in LabVIEW, please see the shipping example LabVIEW <-> Serial.vi. This can be found from LabVIEW by going to Help >> Find Examples. From the example finder, select Hardware Input and Output >> Serial >> LabVIEW <-> Serial.vi.
Once you are able to read the string data in, you can use the VIs in the String/Number Conversion palette to convert the data to numeric format. To access these, right-click on the block diagram >> All Functions >> String >> String/Number Conversion.
Let me know if this does not help.
Regards,
Sean C.
Applications Engineer
National Instruments
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I'm building a heart rate monitor as a final year project with my lab partner using the NI USB-6009 and Labview 2009. We have managed to obtain a signal using a photo transciever, smooth it out and count the events, however the count is incremental.
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Attachments:
TCRT-1010DAQ_jeshua1.vi 367 KB -
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How to decode a set of datas received from serial port and display image on a canvas based on CVI ?
Hi !
I have received a set of datas via rs232 and it contains picture messages. I have to decode the datas first and then display them on a canvas.
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Attachments:
Decode and display image.zip 212 KBWell, things are getting a bit clearer now.
1. Your image is actually 240x240 pixel (not 320x240 as you told before). The size of image data is 57600 bytes which corresponds to that frmat (I was puzzled by such a data size compared with larger image dimensions!)
2. The image is a 8-bits-per-pixel one; this means that you must provide a color palette to create the bitmap
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My contributions to the Developer Zone Community
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Hi,
I have a custom h/w which reads the data from GPS Rx and after parsing send it to PC over RS232.
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jayant
Attachments:
Telemetry_Receiver_v2.zip 3075 KBOne of the most common problems in serial communication is the need for an adequate timing: how much time is expected your device to spend before answering? Have you put and adequate pause in your code before reading from the serial port?
Hope this helps
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Reading ascii codes from serial port and plotting them
Hello
I am trying to build a VI that reads data (ascii values) from the serial port.
I am trying to build a wireless phonocardiogram. I have a microphone that acquires heart sounds. these signals are amplified and sent to a A/D converter to digitize them. the digital signal are sent to a base unit. The digitals signals received at the base unit have to be sent to a computer (over a serial port to view them).
I would like build a VI to plot ascii data received over the serial port.
I would like to plot those values so that the plot just looks like a analog signal (the one I had before A/D conversion).
Can anyone provide me some help?
Thanks in advance.....
Solved!
Go to Solution.Hi chaitu209
What is your transmission speed, samplerate, and bandwidth needed in your project? The bandwidth of the serial port is somewhat limited. Let me give you an example
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How could I choose some bytes from HEX string and then convert it to a decimal value?
Hi I am working with an OMRON E5EN temperature controller using VISA serial to get data, I send the Read from Variable Area command and get this string in hexa 0230 3130 3030 3030 3130 3130 3030 3030 3030 3030 3041 3203 71 or .01000001010000000000A2.q in ASCII this string means:
02 STX
3031 3030 Node and subadress
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I want to choose the eight bytes for the temperature data and convert it to a decimal number. I have seen the examples to convert a Hexa string to decimal but I do not know how to choose the specifics bytes that I need.
I have look for a driver but i didn´t find any. I am a beginner so please include especific topics for me to study in your answer.
Thanks
Carlos Fuentes Silva Queretaro MexicoIf the response always has the temperature starting with byte 15 and is always 8 bytes in length, you can use the String Subset function to get those bytes out of the string. Then use Hex String to Number to convert to a decimal number.
Well someone already beat me to the solution:
Message Edited by tbob on 01-04-2008 04:42 PM
- tbob
Inventor of the WORM Global
Attachments:
HexStr2Decimal.png 7 KB -
I send the frame by a microcontroller ( 8bits) the fram contains 6 bytes, 2bytes conform a long variable, I want to decode the frame and make operations with these long variables and then plot them
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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 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,
NehaMy 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();
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Reading a char array from Serial port
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Hi, I've got the following problem - I wanna read a input stream from serial port and I use at the moment the following method (reading bytewise):
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} catch (IOException e) {}
return fStrBuf.toString();But it doesn't seem to work :-(May I suggest that you use StringBuilder rather than StringBuffer. It has less overhead because it is not threadsafe. I do synchronous serial port stuff with Opto 22, and i have no listeners enabled.
Appending to the String(Builder/Buffer) directly from the byte buffer mangles it. So I use a string (ugh). With the Opto22 brain boards, i am looking for a carriage return as a term char. It either finds it or times out.
This is the best i have come up with so far:
StringBuilder response = new StringBuilder();
String data = new String();
long msTimeOut = 2000;
public void getResponse () throws IOException {
byte[] readBuff = {0};
int charAvail;
response.delete(0,response.length());
long ts = Calendar.getInstance().getTimeInMillis();
try {
while ( readBuff[readBuff.length-1] != '\r' ) {
charAvail = inputStream.available();
if ( charAvail > 0 ) {
readBuff = new byte[charAvail];
inputStream.read(readBuff);
response.append(new String(readBuff));
if ( Calendar.getInstance().getTimeInMillis() > (ts + msTimeOut) ) {
response.delete(0,response.length());
response.append("TIMEOUT");
break;
} catch (IOException e) { e.printStackTrace(); throw e; }
data = response.substring(0);
} I just starting writing Java about 4 days ago, so caveat emptor. -
Using substring to pick the numeric value from a string failing
Hi,
I have a string like fffd_1234.com from this I need to pick the numeric value from which is in between the _ and . , for that I have wriiten the expression as
Reverse(SUBSTRING( REVERSE( "fgfg_asdd.com" ),
FINDSTRING(Reverse( "fgfg_asdd.com" ), ".", 1 )+1 ,findstring(
Reverse( "fgfg_asdd.com" ),"_",1 )-FINDSTRING(Reverse("fgfg_asdd.com"
), ".", 1 )-1))
This is throwing me the error or its giving me with the result with _123.Why all the "reverse" calls? Do you expect underscores or periods to occur more than once in the file name?
This should work:
SUBSTRING("fffd_1234.com", FINDSTRING("fffd_1234.com", "_", 1) + 1, FINDSTRING("fffd_1234.com", ".", 1) - FINDSTRING("fffd_1234.com", "_", 1) - 1)
Talk to me now on
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