Re: CRC checksum algorithm
Dick,
Not sure the protocal, just rs232 serial string. It calculates it over the
data only, not using the header, not sure if there is a trailer. From the
PLC manual I am to send a request and the PLC responses with the data. Both
the send a receive have a checksum of CITTA.
I had sent you an email asking about the DesktopIO form you site. How would
you use this control and look for a delimeter? Specifically if the buffer is
of size catch a string message and keep the rest.
Thanks
wg
"Dick Grier" <dick_grierNOSP AM@msn.com> wrote in message
news:u5b8dnkfFH A.1204@TK2MSFTN GP12.phx.gbl...[color=blue]
> Hi,
>
> What protocol? Some protocols calculate the CRC over only the data (not
> the packet header and trailer), and some calculate the CRC over the entire
> packet.
>
> Dick
>
> --
> Richard Grier (Microsoft Visual Basic MVP)
>
> See www.hardandsoftware.net for contact information.
>
> Author of Visual Basic Programmer's Guide to Serial Communications, 4th
> Edition ISBN 1-890422-28-2 (391 pages) published July 2004. See
> www.mabry.com/vbpgser4 to order.
>
>[/color]
Dick,
Not sure the protocal, just rs232 serial string. It calculates it over the
data only, not using the header, not sure if there is a trailer. From the
PLC manual I am to send a request and the PLC responses with the data. Both
the send a receive have a checksum of CITTA.
I had sent you an email asking about the DesktopIO form you site. How would
you use this control and look for a delimeter? Specifically if the buffer is
of size catch a string message and keep the rest.
Thanks
wg
"Dick Grier" <dick_grierNOSP AM@msn.com> wrote in message
news:u5b8dnkfFH A.1204@TK2MSFTN GP12.phx.gbl...[color=blue]
> Hi,
>
> What protocol? Some protocols calculate the CRC over only the data (not
> the packet header and trailer), and some calculate the CRC over the entire
> packet.
>
> Dick
>
> --
> Richard Grier (Microsoft Visual Basic MVP)
>
> See www.hardandsoftware.net for contact information.
>
> Author of Visual Basic Programmer's Guide to Serial Communications, 4th
> Edition ISBN 1-890422-28-2 (391 pages) published July 2004. See
> www.mabry.com/vbpgser4 to order.
>
>[/color]
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