K8056 problem with serial port, VB 2008

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1

Hi,
I 've just finished my K8056 Velleman kit. I Try to write a program in VB 2008 but I don’t really know how to use VB.

here my program, I just want to set the relay n°1 with a button

Imports System
Imports System.IO.Ports

Public Class Form1
    Dim Port As SerialPort = New SerialPort("COM1", 2400, Parity.None, 8, StopBits.One)

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub Essai_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Essai.Click
        Port.Open()
        Port.Write(Chr(13) & "1" & "S" & "1" & "88")
        Port.Close()
    End Sub
End Class

How can I calculate the Checksum, is it really necessary?
what is the code to configurate the serial port, is it correct?

thanks for your answer

fred

2

Sorry, I have no VB2008 experience.
Regarding the checksum calculation, please check the VB6 demo source.

3

ok but do you have any example with VB6?? It should be almost the same program…

regards

4

See above: The source code of the demo program is available for download. It contains all possible commands for this item.

5

You serial port settings are correct :slight_smile:

velleman.be/downloads/files/ … b_demo.zip
Try reusing the calculations made in the VB6 code and see if it works

6

ok thanks for your answer but i think the problem is in the parameter that i try to send to the card: CHR$13 (is it 0x13 in hexa?), adress 1 (in hex?), S (in ASCII code?), adress 1 (in ASCII code?):

00010011 : CHR$13 (ASCII)? or 0x13 in hex
00000001 : adresse of the card --> 1
01010011 : instruction ‘S’ in ASCII
00011001 : nb of the relais --> 1 or 0x31 in hex

10000000 : addition
01111111 : 2-complement
00000001+: add one

10000000 : checksum=128??? is CORRECT??

Nothing happen on the card but with the demo program, it’s working…
fred

7 
13 = 0x0D
 1 = 0x01
83 = 0x53
49 = 0x31

i’m not entirely sure, but try 18 (0x12) as the checksum
in hex: - (FF - (0D+01+53+31)) = -6D = 12

8

ok thanks but what about the +1??

I understand (FF - (0D+01+53+31)), I suppose it’s the 2-complement but why do you put a “-” before all the equation??? (sorry i’m a beginner)

fred

PS: I suppose that the Led D10 on board is red only in case of a good communication between the card and the pc??

9

Hi,

Just to say that I found the error: Here my program in VB2008 just to communicate with the K8056 board and set the relay one. I can send you the code when i will finish it if you want.

[code]
Imports System
Imports System.IO.Ports

Public Class Form1
Dim Port As IO.Ports.SerialPort = My.Computer.Ports.OpenSerialPort(“COM1”, 2400, IO.Ports.Parity.None, 8, IO.Ports.StopBits.One)

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Port.Close()
End Sub

Private Sub Essai_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Essai.Click

    Dim messagestring As String
    messagestring = Chr(13) & Chr(1) & "S" & Chr(49) & Chr(110) 'number in decimal
    messagestring = messagestring & messagestring
    messagestring = messagestring & messagestring

    Port.Open()
    Port.Write(messagestring)
    Port.Close()
End Sub

End Class[/code]

Thanks for your help…

see u

PS: for the checksum in hexa: [FF-(0D+01+53+31)]+1 = 6E or 110 in decimal

10

Hi all

I found out that the formula of the demo program may get a wrong checksum of 256 while using the command “Send a Byte” with the value 176.
That’s why I came to the following solution to get the checksum for the K8056 in VB6:

Public Function funcChecksum(bytAddress As Byte, strCommand As String, bytValue As Byte) As String

Dim X2 As Integer

X2 = 13 + bytAddress + Asc(strCommand) + bytValue
X2 = Not (X2)
X2 = X2 + 1
X2 = X2 And 255

funcChecksum = Chr$(X2)

End Function

11

hi all,

Here a routine function in VB2008 that works with the good formula for the checksum… address, command and relay_nb are integer.

[code] Public Function instruction_card8056(ByVal address As Integer, ByVal command As Integer, ByVal relay_nb As Integer) As Integer

    checksum = ((255 - (13 + address + command + relay_nb) + 1)) 'complément à 2 des 4 bytes

    messagestring = Chr(13) & Chr(address) & Chr(command) & Chr(relay_nb) & Chr(checksum)
    messagestring = messagestring & messagestring       'double envois de la commande
    messagestring = messagestring & messagestring       'double envois de la commande

    Port.Open()
    Port.Write(messagestring)
    Port.Close()

    Sleep(200)      'pause de 200ms entre 2 commande

    Exit Function
End Function

[/code]
Some define in the beginning of the main:

    Dim relay8 As Integer = 56 ' number "8" in ASCII
    Dim relay_on As Integer = 83 ' "S" character for SET
12

Here is a vb sub for sending the command “B” (send a byte)
using Val7654’s formula

[code]Private Sub K8056_SendByte(Relays As Byte)
'oparates 8 relays of k8056 with address address

Dim checksum As Integer

checksum = 13 + address + Asc(“B”) + Relays
checksum = Not (checksum)
checksum = checksum + 1
checksum = checksum And 255

factor = RTrim(LTrim(Chr$(Relays)))

messagestring = Chr$(13) & Chr$(address) & “B” & factor & Chr$(checksum)
messagestring = messagestring & messagestring
messagestring = messagestring & messagestring
MSComm.Output = messagestring
End Sub[/code]