VB.Net And RS232 Communication ??
Hi everyone !
In the past I've done several projects under VB6 to talk to measurements devices hooked to the RS232 ports of the computer. I used the MSComm-Control for this.
Now I'm making the transition the VB.NET, and I don't see how I should do this RS232 communication, as the MSComm isn't shipped with VB.Net...
Has anyone some information, pointers or hints as how I may implement serial communication under VB.Net ??
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i am trying to get data from a device using rs232 port.
until now i have written the following
Private Sub cmdGetData_Click()
txtDisplay.Text = MSComm1.Input
Private Sub Form_Load()
'Dim Instring As String
' Use COM1.
MSComm1.CommPort = 1
' 9600 baud, no parity, 8 data, and 1 stop bit.
MSComm1.Settings = "9600,N,8,1"
' Tell the control to read entire buffer when Input
' is used.
MSComm1.InputLen = 0
' Open the port.
MSComm1.PortOpen = True
i was expecting to get data continously in the textbox from the device. but it shows only once. and then nothing. do i have to put in some loop?
kindly advice how do i proceed in order to get data continously from the device. also please tell me how to save the data once i get them.
any help will be greatly appreciated.
thanks in advance.
Hi, I want to create an application that reads from a RS232 port (COM) and print the data received on the screen. I have an RF module connected to the RS232 so the data is an analog waveform.
I want to be able to read and transmit data through the COM port. I do not have much experience with comm. ports.
Any help or source where I can look into is appreciated.
I'm working on a Robotics project.
Using VB6 (SP3)
RS232 Communication With I2c Protocol
Does anyone have some expeciance with programming an i2c interface on the serial port on a windows xp system.
I'm want to make a sort of thermometer.
I've made a interface that uses the RTS/CTS lines from the rs232 for making the SCL signal and the CD/DTR lines from the rs232 for the SDA line.
The SCL line is the clock line and should have frequency of 100kHz, this line must be generated by the rs232.
The SDA line is an input and a output.
First it should generate the 8 address bits: 10010001
Where the first 4 bits are the fix, the 3 next bits the address of LM75 and the last should be 1, so the LM74 knows that we want te read information.
The the LM 75 sends 9 bits to the rs 232 contaning the information about the temperature.
Is there anyone that knows how to start with this topic.
I tried with MSComm but .... like I'm a newbie it is not very clear for me.
I even don't know how to generate the SCL (clock signal) line of 100 kHz on the RTS/CTS line
I attached the diagrams containing more information.
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I need to send and riceive string from an instrument by com1 interface and excell 2000, iI have written this lines:
Dim var As String
var = "*cls"
Open "com1: 1200,n,8,2,rs,cd,lf,pe" For Random As #1
Put #1, , var
but the instrument gives me the following error:
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I know very little about using RS232 communication for anything other than just straight Rx Tx kinda communication....
I think that it has to have at least 4 output bits
is this right?
if so I need to manipulate the values of those.
I would need to send a sequence of...
Don't try to make sense of this, it is just to talk to hardware, and this is the sequence it needs to work. So this is basically what I need to do, I have a c++ program to do this through the parrell port, but it is very very slow, and I was wanting to take advantage of the higher baud rates that the RS232 hardware allows.
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I'm building a tool to simulate a portion of an embedded system. I need to be able to use the RTS and CTS lines on the PC's serial port for out of band signaling. Example: I'm physically connected to a device via a standard 9 wire serial cable. When I want to let the device know that I'm ready to send data, I need to set the RTS line high. In response, the device will set the CTS line high. This lets me know that the device is prepared to receive and send data over the normal receive and send lines. Is this even possible using the MSCOMM control and VB? If not VB, can I do this is C?
Any help is greatly appreciated.
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the camera address is 01
i am running this with visual basic and have come up empty at the momemt
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i'm quite new to vb6. I'm trying to send the data via RS232. I used MScom. I send out 1 Byte at at time. I can see the correct data on oscilloscope. But the problem is that between each byte is about 3ms of delay occuring.. the stop bit stay high for about 3ms and another data byte is send out.. But the strange thing is that all data byte looks correct... my question is that, on my laptop i'm using USB to RS232 converter.. Is it causing the problem.. no RS232 on my notebook ( ) .. ok currently no desktop PC available... pls i'm really mad...very urgent to go further.. Thx..
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hi all, im a newbie and have got the coding below to read information in from a PIC Microcontroller.. Could anyone suggest how to change this code to send information the opposite way- out to a microcontroller???
All help greatly appreciated.
Private Sub CmdScan_Click()Dim startedOn Error GoTo Errorhandlerstarted = False DoEvents Timer1.Enabled = True Instring$ = "" TxtInput.Text = "" Done = False If MSComm1.PortOpen = False Then MSComm1.PortOpen = True End If lblaction.Caption = "WAITING FOR SCAN" Instring$ = "" Do While Not Done DoEvents Do While MSComm1.InBufferCount > 0 started = True DoEvents Instring$ = Instring$ & MSComm1.Input Timer2.Interval = 100 Timer2.Enabled = True Do While Timer2.Enabled = True DoEvents Loop Loop If MSComm1.InBufferCount = 0 And started = True Then Done = True End If Loop TxtInput.Text = Instring$ Timer1.Enabled = False If MSComm1.PortOpen = True Then MSComm1.PortOpen = False End If lblaction = Len(Instring$)Exit Sub
I was wondering does anyone know how to develop a form to read a value I am picking up via rs232?
I have using a PIC 16f877 Micro and a ds1620 temperature sensor - at the minute I am sending the temperature via rs232 just to hyperterminal - i want to hopefully develop a Visual Basic form to take the rs232 value and display it, etc. Any help would be greatly appreciated.
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I connect my mobile phone to my pc via a cable. I open the Hyper Terminal and I write:
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When I push the button “setup port 1” the program must to send the command “AT+CMGW” to the phone. The second window opens (picture2) end firtly I must write the text. When I push th button (ok) the program must to send the text and the command (control+Z) to the mobile phone.
Can anyone help me with the code please?
Thank you very much.
I am new to evb. I have downloaded embeded visual basic 3 and had a play with it. It seems to be quite similar to std vb. I have some questuions.
1. Will i be able to make an aplication for ce 2003? It seems to only ask me if I want to create one for ce2002 when I make a new project.
2. When I go to add a component, there is no ms comm addin. Is there an easy way I can talk to the com port. I want to receive and send data to it.
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I have to reset (space = 0) the TXD pin of serial Port Rs232 fo 2 second. I can't do it with the MsCom object. I think there is a low level way to do it , like C with the inport instruction. Do you know the inport (input to the port I/O xxx) instructio for VB?
Thanks for Help.
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i am now facing some problem in sending data n receiving data by using serial port. i connect my com port 1 to a MAX232. i had short circuit pin11(T1In) and pin12(R1Out). thats mean i will receive the same data that i sent. i did this circuit to test on my vb program wheater it can send and receive data to / from an external circuit.
i tried an software named CommSniffer and i can receive the data i sent, thats mean my circuit is ok. but i failed when i try it with VB6. i have trying and modifying on many samples in this forum but none of them work for me.
1 of my reference is the sample from this thread:
can any1 please hep me on this???
I am having some timing issues with a data stream via RS232. From this propritary signal, I get two data lengths 856 bytes and 546 bytes. and the data feed is continious. Both have a <SOH> = &H01 and <EOT> = &H04. My problem is on starting my VB, is i randomly can jump in the middle of all this. There are no control lines to signal a starting point. How do I get around this continious feed and capture the data stream on the <SOH>
Thank you for any support!!
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does any one hex format of mp3 file
i think it is stubid quasition but i'm try to store this files through serial to
pic then into flash memory so i need to know how to start to transmit the file
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b4, ive been working on usb communication using vb with the help of jan axelson's sample code. it works well.. n now i want to learn about rs232 n really need a sample code.
Hey, I got a serial cable connecting from one of my PC to another. I am looking for VB code or existing program that allows me to transfer files between the two PCs.
Newby On RS232 Again
What do I do wrong?
I would like to "synchronize" the incoming message somehow. I mean I don't want to see any truncated "Hello world!" messages but it does happen sometimes. I tried this:
Private Sub MSComm1_OnComm()
If Flag = 0 Then
Do Until MSComm1.Input = "H"
Flag = 1
Temp = Temp & MSComm1.Input
Text1.Text = Text1.Text & Temp
The goal would be to use Flag to indicate synchronization. Flag would be set to 0 in form_load() so in the first time the If/then block should be fired. In this block the loop would wait until the incoming character is "H", the first of the "Hello world!", then set the Flag (now it is "in sync"), then leave the if/then block and capture all incoming message.
The flag would be zeroed after clicking on "Close port", because next time the port is opened chances are there'd be no synchronization :-)
Needless to say the above rutine does not work :-) What's wrong?
Gurus out there?
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I am trying to connect to a GPS using a VB app and the GPS vendor tells me that I need to enable the 7 PIN on the rs232 port that is the RTS (request to send) pin.
I have tried the following code from another posting but still can't get it to work
Private Sub Command1_Click()
MSComm1.CommPort = 1 ' set the port
MSComm1.Settings = "1200,n,8,1" ' set the settings
MSComm1.RThreshold = 1 ' how many characters received per onComm event
MSComm1.PortOpen = True ' open the port
Private Sub MSComm1_OnComm()
Select Case MSComm1.CommEvent
Text1.Text = MSComm1.Input
I don't understand how I "enable" the 7 pin (RTS) that effectively starts the GPS running. Can any one help??
In my application i need to receive string (ok ng) value from rs232 cable .the value will sent by microprocessor..
how to i convert the value into string??
or otherwise what mode i need to set in the mscomm control for receive string value??
waiting for your valuable reply...
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in my application i need to read the value(weight) from weight machine..the weight machine connect thru rs232 cable..i understand that i need to use mscomm control..whenevr i receive i need to display in the textbox and once i receive i need to stored inside the database..
but how to i do ??
is there any example source??
if u have information or example source pls pass to me..
waiting for yuor value..
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Hi i need to make communication with a device through COM port but for some reason i can't get input. When i'm using a com monitor program like docklight i send a command and the device respond, but when i try this from vb program(using MSComm Control) the device react on the command but i can't get response !? That's strange ! I'm handling OnComm event but there is no event to be handled after i send the command ! Any ideas ? Thanks in advance !!!!
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My program work OK with a normal RS232 or a PCMCIA card , but whit the USB->RS232 , the only thing that move is the RTS DTS , but TX and RX , nothing ?
Any idea is welcome
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sometimes (rarely) the delay between one transmit to the other transmit is more then 500 msec
anybody know what can cause such a thing?
I tried setting my application thread to 32 priority (which is realtime priority)so it will be the most important thread and that no other thread may enter before it and delay the transmits but still I get sometimes more then 500 msecs between two following transmits...
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I have some simple code that works as an .exe but when I make it an Active X it doesn't work.
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I would like to build a VB app with the ability to control pan/tilt/zoom operations of a Sony camera via RS232 com port.
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Many thanks, Daniel.
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In concrete I just need to enter 1-2 bytes in a form on web page,
and to send it on serial port. How can I do that?
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Can some one there help me please.
I need to build Command string to send to serial port (RS232) with Windows XP Proffesional
Com is COM1
Baudrate is 9600
Stop bit 2
Serial protocol FULL DUPLEX
ENQ = reset communication (PASSWORD)
ACK = command acknoweledged
NAK = command not acknoweledged, try again
error = information about error type
command and answer
STX + 0x03 + POINTER + ASCII1 + ASCII2 + ... + ASCII10 + ETX + CHK
STX + 0x03 + POINTER + ETX + CHK
POINTER = 10 (but in hex format)
ASCII1 + ASCII2 = 2 (but in bcd format)
ASCII3 + ... + ASCII10 = some characters like words
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Thanks in advance for any info on UPS/VB info.
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I am using RS232.vb class to develop an application to communicate with a card-reader attached to the serial port on my system. The code is working properly.
Data is sent and received properly. My problem is that none of the events of RS232.vb are fired.
My declaration line for RS232 class goes like this:
Public WithEvents CommPort As New Rs232
What should I do to get the events fired ?
thanks in advance
for your reference, RS232.vb is available at :
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Using MSCOMM control.
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I can get my reading on screen no problem running the program from within vb,but when i compile the program and install it on the same pc
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MMM....Why is there a delay after it is compiled.
Has anyone ever experienced this before..
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can anyone help
i can recieve data from my device but i try to update a access table with the recieved data it does not work correctly. my form has ado control on it connecting to the db.
While blnStat = True
If MSComm1.InBufferCount Then
str = str & MSComm1.Input
txtFields(0) = Right(str, 23)
when i add in the line (datPrimaryRS.Recordset.AddNew) into the if statement my recordset jumps three records each time.but when i manually add a record using the add button it works fine but does not work using code.mmm
has anyone got any source code to do a similar thing in access
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i have received from the vendor of a device for cars the information in order to obtain a real time info from the engine.
Here is the info he has sended to me:
Data starts streaming 15 seconds after power up.
> >Output Data Format
> > RS 232
> > Baud rate 9600
> > Data 8 bit
> > Parity None
> > Stop 1 bit
> > Flow Control None
> > Header block
> > #00 null heading
> > #01 start heading
> > #02 start text
> > Data block: data format
> > AFR HEX 8 bit
> > EGT LSB HEX 16 bit
> > EGT MSB HEX 16 bit
> > RPM LSB HEX 16 bit
> > RPM MSB HEX 16 bit
> > Boost LSB HEX 16 bit
> > Boost MSB HEX signed
> > TPS HEX 8 bit
> > User1 HEX 8 bit
> > Config Register HEX 8 bit
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Can anyone give me the way in order to receive the info?
Thanks very very very much in advance.