"Gokul" <[EMAIL PROTECTED]> wrote:

>I am trying to acquire data using LabView from KV16AR
>PLCs data memory. A program in PLC is going to dump
>data in PLCs data memory and LabView is going to
>simultaneously acquire it. The transmission is over
>serial port and I have done serial port acquisition
>before with temperature controllers. 
>
>I felt both type of acquisition are the same...but
>still wanted to ask... Is this any different? ... I
>have never worked with PLCs before..thats why wanted
>to know.  

Well serial programming is serial programming! But then
no device or protocol is really the same. RS-232 means
recommended standard and is not always followed to the
word but even then only really specifies the electrical
chararacteristics.

The protocol depends on the the more or hopefully less
warped mind of the original developer. As long as it is
decently documented there is always a way to make it work,
serious bugs in the device firmware excluded. If you have
working C or even Basic sample code that usually helps too
to understand what the protocols intimate details are.

There is no reason to assume that PLCs are worse or better
in their design of the cummunication protocol than any other
device, other than there might have been a tendency in the
past to cook up its own protocol to make sure they can sell
their own programming tools and peripheral devices.

Rolf Kalbermatter
CIT Engineering Nederland BV    tel: +31 (070) 415 9190
Treubstraat 7H                  fax: +31 (070) 415 9191
2288 EG Rijswijk        http://www.citengineering.com
Netherlands             mailto:[EMAIL PROTECTED]
 



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