Modbus Data Frame, CR+LF HExadecimal Conversion?
Oct 18, 2010
i m working on an application which communicates with PLC machine using Modbus protocol. Now i m able to generate and communicate a modbus data frame with PLC the only problem that i m facing is that in all the data frames of modbus the last ascii characters should be Carriage return + Line feed which should be read by the PLC as 0D 0A that is in Hexadecimal form. But i m not able to do this. The rest entire string is properly read by the PLC but How do I make it read the CR+LF.
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Nov 25, 2009
I'm writing a small program that will convert a negative number (e.g. -200) to a hexadecimal number (e.g. FF38). And back to a decimal number. FF38 back to -200. (I can only use two bytes when converting back and forth.)
Question: is there a function in VB that will help?
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Mar 1, 2010
I am currently working on a software that will convert a string to it's hexadecimal equivalent and back. I have created the following code to make the convert the string to hexadecimal, but I cannot figure out how to get it back.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim skill As String
skill = RichTextBox1.Text
Dim skillfullbyte() As Byte
[code]....
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Sep 1, 2009
I am writing a program and have run into an issue. The program requires a conversion of time (e.g. hours,minutes,seconds) to a hexadecimal value of no more than 4 bytes (e.g. FFFF). I have no idea how this is done. Can anyone point me to a tutorial or give a quick explanation. Sample code would be great as well.
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Mar 2, 2012
I have a modbus TCP device that I have managed to connected to through my VB source code.
I want to poll (continueously read) data from certain registers of the device, and store the polled data in a file (text,csv, excel).
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Oct 27, 2009
I have a Form with 4 Text Boxes, 1 label and one button. What I need to do is: Make all the text boxes and label only except Hexadecimal inputs.when I press Button1
Label1 = TextBox1 AND TextBox2 ^ TextBox3 MOD TextBox4
Once again every all the numbers are in Hexadecimal format.
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May 20, 2012
[Code]...
I can access a specific frame and put the frame into a bitmap so that I can process the bitmap.
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Jul 14, 2011
I have two frames in a frameset with some textboxes in one frame and a button in another frame. How can i get the data input from the textboxes in the first frame, on a click of the button in the second frame?
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May 5, 2010
I'm trying to access a device with modbus in VB or C#. I've been searching all over for a simple way to do it. I know that It would be connecting through a TCP Connection, and I know the address of the device. I need to read the input on it (whether of not it's on), and to toggle the relay on it as well.
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Jul 11, 2010
I want to develop Modbus RTU Master program ..
I am expert in Modbus communication and I have designed the Modbus pre-programmed remote controls ,, Now I want to interface some Modbus RTU slave devices to my own developed application ...
I am much familiar with the Modbus RTU syntax and I've tried following to initiate the the master query but I am getting initial 3 bytes ok ,, rest of the bytes are changing the values on COM port so slave is not responding to my command ..
CODE:
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Jun 4, 2012
I am using datarepeater to display rows of information from database. When i click a 'save' button and i would like to loop through the rows of data in repeater. The code i am using is able to do all these. The only problem i encountered is at the Interface side. When i am looping the data-repeater. The selection 'frame' (refer to the picture point as 'A') is moving from record to the next record and scrollbar is auto moving as well to scroll to further down until the last row where looping finish.Is there anything can be done to remove the selection 'frame' and stop datarepeater from scrolling while looping the datarepeater.
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Jul 11, 2010
I want to develop Modbus RTU Master program ..I am expert in Modbus communication and I have designed the Modbus pre-programmed remote controls ,, Now I want to interface some Modbus RTU slave devices to my own developed application ... and looking for kind guidance ..I am much familiar with the Modbus RTU syntax and I've tried following to initiate the the master query but I am getting initial 3 bytes ok ,, rest of them are changing the values on COM port so slave is not responding to my command ..
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Private Sub Button10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button10.Click
Dim BYTE1 As Byte = 1
Dim BYTE2 As Byte = 6
[code].....
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Mar 8, 2012
I am developing a software that will monitor/poll serveral Modbus/TCP devices on a network.
I have managed to connect to one device using VB.Does anyone know of a driver or perhaps a 3rd party software I could use that will enable me to connect to more than one Modbus/TCP device?
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Apr 19, 2010
I need to interface between a PC and a Microcontroller based Controller to transfer data between the PC and the Controller?
Ive got acces to the register numbers or names in the Microcontroller.
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Jul 15, 2011
Im getting that error in the da.Fill(ds)
Imports System.IO Imports System.Data.SqlClient
[Code]...
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Oct 30, 2009
how does this function works. How does it copy the frame? HDC BiBlt???
ublic Function copyFrame(ByVal src As PictureBox, ByVal rect As RectangleF) As Bitmap
If isRunning Then
Dim srcPic As Graphics = src.CreateGraphics[code].....
the above function is called from the below command which is in a timer event. mycam is a class including the copy frame function.
bm2 = myCam.copyFrame(PictureBox1, New RectangleF(0, 0, PictureBox1.Width, PictureBox1.Height))
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Aug 1, 2009
I am working on an application that will need to read tons of records (close to 500,000) from one table and insert them into another set of tables in the same database. I though about using SSIS package for this but our DBAs don't want to use that. Now, I am thinking of a multi-threaded approach. I am thinking that I can have a few thread started that will read say (500) records at a time and insert them, then come back and read more.
Now, say I spawn off 3 threads of this application. The first thread reads 500 rows and starts processing them. Can I lock these rows that were already read so that the next thread does not pick them up? I am trying to find some articles regarding this on the internet, but perhaps I am not searching for the correct terms in Google.
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Jan 19, 2012
I have eight text boxes each can have any numerical value only consisting of the numbers 1-8 up to eight digits each. No 0's or 9's.I am using a timer to loop through the sequences of text boxes at a given rate. This is already configured.Now here's the hard part so bare with me.I need to output the first value of a text box, wait some time then output it's counter letter (below the number on the keyboard), go to the next text box and repeat. Example:
1
34
765
[code].....
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Jun 15, 2012
Here's the function I'm a bit mystified by(Little rusty bitwise operators)
void two_one(unsigned char *in,int in_len,unsigned char *out)
{
unsigned char tmpc;
int i;
[CODE]...
I marked the two places that I don't quite understand. How to convert those pieces to Vb.Net.
Update: So this is what I came up with, but it's not quite giving me back the right data...Anything look wrong here?
Public Function TwoOne(ByVal inp As String) As String
Dim temp As New StringBuilder()
Dim tempc As Char
[code].......
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Oct 26, 2010
VB 2008 Express edition. I'm pretty new to VB2008, a little over halfway through my first classi am writing a console program to ask the user for the price of gas for 7 days, then to get the average of that price. here is my code so far:
Option Strict On
Module Module1
Sub Main()
[code].....
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Jun 8, 2011
I`m trying to write a programme ,in VB2008 Express, to receive Serial Port Ascii data ( from a Multimeter) and display it as Hex Data in a textbox. I can get the Ascii data to show, but just cannot convert it into Hex. Once I can do this I want to write a new front end for the Mulimeter software.
This is what i`ve written so far :
Imports System
Imports System.IO.Ports
Imports System.Text
[Code].....
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Jan 18, 2012
I have eight text boxes each can have any numerical value only consisting of the numbers 1-8 up to eight digits each. No 0's or 9's. I am using a timer to loop through the sequences of text boxes at a given rate. This is already configured.
Now here's the hard part so bare with me.I need to output the first value of a text box, wait some time then output it's counter letter (below the number on the keyboard), go to the next text box and repeat. Example:
[Code]...
Ultimately I'm trying bring my PC Interface project up to date by going from a parallel port to USB. This will be the "Custom Loop" function for the device.
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May 7, 2009
I'm writing a C# application that reads data from an SQL database generated by VB6 code. The data is an array of Singles. I'm trying to convert them to a float[]
Below is the VB6 code that wrote the data in the database (cannot change this code):
Set fso = New FileSystemObject
strFilePath = "c: emp emp.tmp"
' Output the data to a temporary file
[Code]....
The problem here is the VB6 binary to string conversion. The VB6 string char is 2 bytes wide and I don't know how to transform this back to a binary format I can handle.
Below is a dump of the temp file that the VB6 code generates:
And here is the dump of the data as I read it from the database in (=the VB6 string):
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Jun 3, 2012
I am trying to retrieve and display data from MySQL database to vb.net console window using the following code
myconnection = New MySqlConnection("Server=localhost;username=root;password=;database=agro-system;")
myconnection.Open()
cmd1 = New MySqlCommand("select * from sales", myconnection)
myreader = cmd1.ExecuteReader()
While myreader.Read()
[Code] .....
But I get the following error:
Unable to convert MySQL date/time value to System.DateTime
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Mar 2, 2011
Just wondering what the preferred/practised data type conversion technique is?
For example I recently enabled option strict, which in turn found quite a few errors in relation to data types, vb.net prompted me to use CType, which is fine.
However, I have seen other functions for data type conversion, such as .tostring, CInt , Convert, integer.parse and also Ctype.
Why would you use Ctype over the others?
I know its a pretty primitive question , but why do so many conversion methods exist?
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Sep 2, 2010
I'm working on a form that allows to add new users to a users table in my Access database. The table only has 3 fields: user (string), password (string) and admin (boolean). user is the primary key. But when I run it and try to add, I get an error when casting the query to Double (?). I don't have any double variables or table fields, and I'm not trying to cast anything from or to double. So I have no clue about how to fix this. The code I'm using to insert (and it's working correctly on other forms and tables I have) is:
[Code]...
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Oct 17, 2011
I don't know how to convert the nvarchar value into an int, but that is the way it needs to be set up. I've found other posts about this but I don't know how to use CAST in the INSERT statement I have. All the posts I could find were about converting to int in SELECT statements. I need this statement to change the field @Duration to an int in the database. @Duration is an amount of time. (01:00, 02:00...) They will all get rounded up to the next int value. So if a user enters 0:45, it should be converted to 1. how to get this INSERT to work?
'SQL Insert: Product table
Dim sqlInsertProduct As String = "INSERT INTO Product (ProductName, Status,
CreateDate, ModifyDate, CreateUser,
[Code]....
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Mar 11, 2010
[code] My project topic is on data conversion for length and weight. There is something wrong with the code.
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Aug 11, 2011
im using vb 2010 and currently working on a program that senses and displays values in hexadecimal, i have already done this part, but now im required to convert the value that is in the textbox, for example 006d to 109.
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Apr 8, 2009
a user will enter a number, n, which ranges from 1 to 30. they will also enter a "P" or an "S" (sum or product). depending on which was selected, it will calculate the sum or product of the numbers from 1 to n.i'm having a conversion error on line 5 stating "Conversion from string "S" to type 'Double' is not valid." [code]
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