[Gambas-user] Modbus on serial port

Werner werda at ...1000...
Wed Sep 14 09:40:29 CEST 2005


ariafrancesco at ...86... wrote:

>I am trying to implement the serial modbus protocol on gambas.
>Bookcase was my intention to create a class that all could use but I have a problem that I do not succeed to resolve.
>The instrument with which I try to communicate seems that it understands what I send but does not answer to me .
>What you know version 1,0,3 of gambas has of the problems with the object of the serial port?  
>
>In order to create the string to send to the instrument I use:
>
>  strOutput = Chr$(CByte(Val ("&H "& strNode))) & Chr$(3) & Chr$(CByte(Val ("&H" & Left$(varTemp, 2)))) & Chr$(CByte(Val ("&H "& Right$(varTemp, 2)))) & Chr$(0) & Chr$(1) 
>
>in order then to send it with:
>
>PRINT # Sport, (strOutput & Chr$(CByte(Val("&H "& Right$(strCRC, 2)))) & Chr$(CByte(Val("&H" & Left$(strCRC, 2))))) 
>
>Is possible that problem is the character set ?
>Gambas use UTF8 character set so is possible that using the Chr$ function the instrument does not understand?  
>
>P.S. I sure that the instrument receives the string , in fact it count the message and understand that it is for he (strNode = "1" node 1 of net modbus 485) 
>
>HELP!!
>  
>Is possible that I'm successful to write an OCX for the modbus in VB6 and does not succeed to make of the porting on Gambas!!!!!  
>
>P.S. 2 :-))  where I can find the rpm of last stable gambas for Mandriva?  
>
>THANKS To ALL
>
>  
>
The latest stable version is 1.0.11. The download for all distributions 
starts here: http://gambas.sourceforge.net/download.html
To find out if there is a problem with character conversion you might 
want to hook up with a second computer using a terminal emulator program 
that can display SOH DEL ESC NUL and all the other control characters. 
Alternatively you could write a small gambas program for it simulating 
modbus simple replies.

Just my 2 cents.

Regards,

Werner





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