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Serial communication STX ETX LRC

Posted by Willy 
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Willy
Serial communication STX ETX LRC
September 05, 2018 10:00AM
Hello

I have to send a a command to a serial device 

<STX>00C100000000100007654321                    0000000000501EUR<ETX><LRC>


I do'nt know what those things like STX ETX and LRC mean.

Can someone help me.

Thanks.

Will Hermans
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harvey68
Re: Serial communication STX ETX LRC
September 05, 2018 10:31AM
Hi,

[ascii.cl]

Kind regards,
G. Predl
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pao
Re: Serial communication STX ETX LRC
September 05, 2018 10:32AM
Hi Willy,
Normally this are hexadecimal control chars.

You can check one ascii table or the device manual to see the hexadecimal values of this chars.

to send the STX you can use the function Charact(02)
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Willy
Re: Serial communication STX ETX LRC
September 05, 2018 10:44AM
Thanks,
So simple.

But there is still one problem. There is no LRC in the ascii table.
The documentation says :

LRC = the exclusive or of 
00C100000000100007654321                    0000000000501EUR<ETX>

I see no XOR in Windev
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ArieM
Re: Serial communication STX ETX LRC
September 05, 2018 10:50AM
Willy,

that's BinaryXOR() in Windev

Arie
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Willy
Re: Serial communication STX ETX LRC
September 05, 2018 10:54AM
Thanks
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slxslx
Re: Serial communication STX ETX LRC
September 05, 2018 05:39PM
Varoius control characters 

cSTX is character = Charact(02) 
cETX is character = Charact(03)
cACK is character = Charact(06)
cNAK is character = Charact(21)
cFS is character = Charact(28)
cRS is character = Charact(30)

Function to calculate LRC 
PROCEDURE get_lrc(LOCAL sString is string)
nLRC is int = 0
nZnak is int 
	//[en.wikipedia.org]
	
FOR nP=1 _TO_ Length(sString)
	nZnak=Asc(Middle(sString,nP,1))
	nLRC=BinaryXOR(nZnak,nLRC)
END

RESULT nLRC

BR,
Alen Uzelac
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