MSComm woes

[renzokuken]

Hi,

I'm trying to write some code to open a serial port and send data to a motorised x-y stage.

i'm trying to do this in a language called ADL (specific to varian scientific instruments) which is based on Sax Basic, which is VB compatible.

I have referenced the MSCommLib .ocx and am using the following code to open the port ready for various bits of data to be sent

Dim OldHandShake As Integer
Dim OldSettings As String
Dim OldMode As Integer
Dim OldInputLen As Integer



Sub PortControl
 
        Dim myCom As MSCommLib.MSComm
          
        With myCom
          
          .CommPort = 1
          .PortOpen = True
          'save current port settings
          OldHandShake = .Handshaking
          OldSettings = .Settings
          OldMode = .InputMode
          OldInputLen = .InputLen
          'set the new settings
          .Handshaking = comNone
          .Settings = "9600,N,8,1"
          .InputMode = comInputModeText
          .InputLen = 1
          .RThreshold = 1
          
        End With
     
End Sub

     

Sub Main
	PortControl
End Sub

when i run the script i get the following error

Error in file C:\Documents...etc..... at line 15 position 0 (10094) ActiveX Automation: Object var is "Nothing". ......

and it highlights the line .CommPort = 1

Sadly im unsure what this actually means. I'm a chemist, not a programmer, thats been thrown in the deepend without a float. I'm learning fast but this has me a bit a stumped.

Any help would be greatly appreciated. Thanks

EDIT: i should also mention that this script has no form/frontend, it is a macro that runs within the Varian Software

[trisuglow]

Try this.

Replace "Dim myCom As MSCommLib.MSComm"

with

Dim myCom As Object
Set myCom = CreateObject("MSCommLib.MSComm")

In normal VB you would have a MSComm sitting on your form. In your case you are having to create a new one.

[renzokuken]

wow, thanks trisuglow, that worked a charm

i sent a command to my stage and it did what it was supposed to......amazing....thanks

heres the code now (including a command to reset both units to their "home" position

Dim OldHandShake As Integer
Dim OldSettings As String
Dim OldMode As Integer
Dim OldInputLen As Integer




Sub PortControl
 
        Dim myCom As Object
        Set myCom = CreateObject("MSCommLib.MSComm")
        
        With myCom
          
          .CommPort = 1
          .PortOpen = True
          'save current port settings
          OldHandShake = .Handshaking
          OldSettings = .Settings
          OldMode = .InputMode
          OldInputLen = .InputLen
          'set the new settings
          .Handshaking = comNone
          .Settings = "9600,N,8,1"
          .InputMode = comInputModeText
          .InputLen = 1
          .RThreshold = 1
          Wait 1
          .Output = Chr$(0) + Chr$(20) + Chr$(0) + Chr$(0) + Chr$(0) + Chr$(0)
        End With
     
End Sub


Sub Main
	PortControl

End Sub

now i want to add a set of predefined instructions to move units to set positions, how does that effect the two lines you advised me to add. they are not global variables or anything and restricted to the "Portcontrol" sub if i understand correctly.

so would the following work

Dim OldHandShake As Integer
Dim OldSettings As String
Dim OldMode As Integer
Dim OldInputLen As Integer




Sub PortControl
 
        Dim myCom As Object
        Set myCom = CreateObject("MSCommLib.MSComm")
        
        With myCom
          
          .CommPort = 1
          .PortOpen = True
          'save current port settings
          OldHandShake = .Handshaking
          OldSettings = .Settings
          OldMode = .InputMode
          OldInputLen = .InputLen
          'set the new settings
          .Handshaking = comNone
          .Settings = "9600,N,8,1"
          .InputMode = comInputModeText
          .InputLen = 1
          .RThreshold = 1
          Wait 1
          .Output = Chr$(0) + Chr$(2) + Chr$(0) + Chr$(0) + Chr$(0) + Chr$(0)     'renumber all units
        End With
     
End Sub

Sub PositionOne
         .Ouput = Chr$(0) + Chr$(20) + Chr$(85) + Chr$(23) + Chr$(7) + Chr$(0)

End Sub

Sub PositionTwo
     .Output = Chr$(0) + Chr$(20) + Chr$(45) + Chr$(3) + Chr$(34) + Chr$(0)

End Sub



Sub Main
	PortControl
        PositionOne
        PositionTwo
        ......etc
End Sub

[trisuglow]

No.

You'll need to put Dim myCom at the top of your file (along with Dim OldInputLen and the others). Leave the CreateObject line where it is though.

In your PositionOne sub you will need to add "With myCom" and "End With" (also elsewhere).

[renzokuken]

yup, thats nailed it, thanks for your help

in 2 minutes you've helped with weeks of frustration.

[trisuglow]

Great!

Glad to be of help. I wish I was programming robots instead of databases...

[ajay.mnnit]

hi
i also need your help regarding to my probs.

I have to transfer a text file through serial port (COM1 ) to other connected end system.

Give me some idea about this

[trisuglow]

Hi,

I've been on holiday so I'm only just seeing this now. Did you start a new thread and get an answer from somebody else?

The simplest way (in principle) is to open a DOS window and type COPY file.txt COM1:

Also in the DOS window, use MODE COM1: to get/set the port parameters.