How to read from an electronic scale (POS app)

Cesar F. Manzano T.

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Mar 1, 2000, 3:00:00 AM3/1/00

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I am developing a Point of Sale application and I bought a NCI 6720-15
(Weigh-Tronix) electronic scale; it has a serial port an cable and all that
I am supposed to do is send "W<CR>" and read "<LF>(weight in numbers)<CR>".

How do I do that?. Do I need a .dll for RS-232 interface? Are the old
FOPEN(), FWRITE() and FREAD() still working for Win98 and VFP6?

Thanks in advance

Rick Bean

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Mar 2, 2000, 3:00:00 AM3/2/00

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Cesar,
Windows (especially NT), doesn't like anyone directly accessing the com
ports, instead use the MS Communications Control (Mscomm32.ocx) - assuming
you are using VFP. See
http://support.microsoft.com/support/kb/articles/Q154/7/41.asp for some
sample code.

Rick

"Cesar F. Manzano T." <cman...@avantel.net> wrote in message
news:#ehhOMBh$GA....@cppssbbsa02.microsoft.com...

Garrett Fitzgerald

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Mar 2, 2000, 3:00:00 AM3/2/00

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In article <#ehhOMBh$GA....@cppssbbsa02.microsoft.com>,
cman...@avantel.net (Cesar F. Manzano T.) quoth...

> I am developing a Point of Sale application and I bought a NCI 6720-15
> (Weigh-Tronix) electronic scale; it has a serial port an cable and all that
> I am supposed to do is send "W<CR>" and read "<LF>(weight in numbers)<CR>".

I would suggest looking into a OLE for POS (OPOS) driver for this --
would make it easier to program, if they have one.
--
Garrett Fitzgerald
#INCLUDE "\Program Files\Microsoft Visual Studio\VFP98\stddsclm.h"
(Anyone who thinks I do anything vaguely resembling speaking for Microsoft
is sorely deluded...)

Cesar F. Manzano T.

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Mar 4, 2000, 3:00:00 AM3/4/00

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Thank You all, I made the scale work and also a PSC VS1200 countertop
scanner; both connected to serial ports.

How to deal with serial ports and MSCOMM32.OCX ? read on

For the scale ...
************
(the trick is to wait)

*** cmdWeight.Click()
SET DECIMALS TO 3 && ** If not, it rounds the weight to 2
decimals
LOCAL el_peso, eran, ns

eran = SET( 'DECIMALS', 1)

WITH THISFORM.oleBascula && *** the name of the object MSCOMM32

ns = SECONDS()
.portopen = .T.
.inputlen = 20

DO WHILE SECONDS()- nS < 1 && ** A loop to read the COM port
.output = "W" + CHR(13) && ** An orden to the scale
&& (it's part
of the NCI protocol)
FOR x = 1 TO 100000 && ** Just waiting ...
ENDFOR

el_peso = .input && ** Here is the weight
measured

el_peso = RIGHT( el_peso, LEN( el_peso) - 1)
el_peso = VAL( LEFT( el_peso, 7))

IF el_peso > 0
THISFORM.txtPeso.Value = el_peso
EXIT
ENDIF

ENDDO
.portopen= .T.
ENDWITH

SET DECIMALS TO (eran)

For the scanner ...
************
(the trick is to use the OnComm event to let the data flow in alone)

*** In the Form Init method...
THISFORM.oleScanner.portopen = .T.
*** In the cmdExit.Click() ( exit button)
THISFORM.oleScanner.portopen = .F.

*** In the ONCOMM Event of the OLE object (THISFORM.oleScanner)
IF This.CommEvent = 2 AND This.InBufferCount > 0 && *** There is something
in the scanner !!

WITH THISFORM.txtClave
la_clave = THIS.input
la_clave = RIGHT( la_clave, LEN( la_clave) - 1) && *** I clean up an
"A" that I get (??)

.Value = la_clave
.Valid()
ENDWITH

ENDIF

Of course I validate that we are entering codes and the cashier does not use
buttons but F-( ON KEY LABEL F10
_ACTIVEFORM.cmdIniciar.Click())