Re: [foxboro] String 2 ASCII
- From: Kevin Fitzgerrell <fitzgerrell@xxxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Mon, 14 Jun 2010 22:22:56 +0900
Khaled,
I'm away from the office now so can't check. In the documentation you can
look up "subset" of an internal string reference. I have not done this in a
long time, but I believe the format was STRING (1 .. 4) or something similar
to use character 1,2,3,4 of STRING.
The "lookup table" is probably going to be a subroutine with a series of IF
statements comparing each character to the allowable ASCII characters to
determine what it is and writing the appropriate output.
This is relatively trivial programming but because of the number of steps
needed to parse and output values for an 80 character string this has the
capacity to put significant load on the system. I would lean towards
processing this on the AW rather than in the controller. On the AW this
would be a straightforward "C" or a trivial Perl program.
Regards,
Kevin
On Mon, Jun 14, 2010 at 8:49 PM, Ahmed K. Sayed <a.sayed@xxxxxxxxxx> wrote:
> Kevin,
>
> Can you give an example of such sequence? Or at least its main
> functions?
> How to read each character individually from a string? How to use lookup
> table inside a sequence?
>
> Thanks,
>
> Khaled
>
> -----Original Message-----
> From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
> On Behalf Of Kevin Fitzgerrell
> Sent: Monday, June 14, 2010 8:43 AM
> To: foxboro@xxxxxxxxxxxxx
> Subject: Re: [foxboro] String 2 ASCII
>
> Off the top of my head I don't see any way to do this without changing
> the
> string to ascii codes on the DCS side.
> You can do this in sequence logic, one character at a time. If the
> operator
> enters a string, you can read that string in to sequence logic, read
> each
> character, use an ASCII lookup table to convert, and then output those
> values to the specified registers as integers or packed.
>
> Regards,
>
> Kevin
>
> On Mon, Jun 14, 2010 at 2:17 PM, Ahmed K. Sayed <a.sayed@xxxxxxxxxx>
> wrote:
>
> > Hello list,
> >
> >
> > I need some help on communication requirement with one MODBUS TCP
> device
> > via FDSI link.
> >
> > DCS has to send some specific string messages indicating package
> status,
> > lot number, time stamp, product type, etc.
> >
> >
> >
> > What I normally do for such requirements is to map those predefined
> > strings to integer numbers, and through graphics or simple CALCA I can
> > send them.
> >
> > The requirements here is bit different, those strings are not
> > predefined, i.e. any text can be entered by operator must be sent to
> the
> > MODBUS device for historical notes recording.
> >
> >
> >
> > The vendor has defined the ASCII mapping he's using, which maps every
> > character to specific register bit coding.
> >
> >
> >
> > Example: if the DCS transmits string "OFF" then the corresponding
> > registers must have the following values:
> >
> > Register 0001 = 464F
> >
> > Register 0002 = 0046
> >
> > Register 0003 to 0016 = 0000
> >
> > Where 0x46 is the ASCII code for the letter "F", and 0x4F is for
> letter
> > "O".
> >
> >
> >
> > I've tried to use STROUT block, but failed to get it to work. It does
> > not accept the allocated MODBUS registers giving "invalid point
> > connection".
> >
> > There isn't any information mentioned the use of STROUT/STRIN blocks
> in
> > FDSI TCP/IP & Serial MODBUS documentation; Only for other DCI blocks.
> >
> >
> >
> > Is there any other built-in function that can do this transformation
> > from string to ASCII?
> >
> >
> >
> > Regards,
> >
> >
> >
> > Khaled
> >
> >
>
>
>
>
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