Wonderware - NETDDE

T

Thread Starter

Tony Chambers

Hi List,
Is anyone aware of any issues with respect to Wonderware and NetDDE. Our site controls network, mostly Honeywell SCAN3000, with AB PLC's through port servers, and Intouch Wonderware is having network problems. The network guys who
are investigating this are starting to point the finger at the NetDDE side of things. Are there any known problems or areas of concern that we should be concentrating on.

Thanks in advance for your time.

Cheers Tony Chambers.
[email protected]
Norfolk
England
 
J

Jamil, Babar

Can you tell what kind of network problems you are having? DDE Multiplexing (i.e. having too many clients to one DDE server) is one possible issue that you can have with NetDDE.

Again it will be easier if you can tell exactly what kind of problems you are having.
 
L
Oh yes, there are many issues:

Are the DDE shares still 'trusted'? If not, and you can only tell from the IOServer machine if they are, then anomalous comm problems will occur every time.
Do you use WinNT, with NT Domains? If so, have any PC or NT Servers newly joined the domain(s) where the NetDDE is used, or possibly changed machine names, changed IP addresses or moved their domain membership? Same sort of
anomalous comm problems. There may be other issues (host table mis-matches between systems, CPU utilization, memory leaks) causing Dr Watson and assorted breakage. We also had some indications that multiple types of NIC's on the same machines (with their differing Enet drivers) were causing some problems.

There may be others that we have not encountered, but it has never been a network problem for us, when we have shaken the system down to debug the
problem.

Larry
 
A

Anthony de la Rosa

it really depends on alot of thing. For starter, how many active topics do
you have? how many PLC's are we talking about here? and lastly, how many
copies of the application are you running? are these machines standalone? or
do you have one machine setup as a master node and the other machines
pointing to this node.

The kBCD says that the practical limit for NetDDE is about 100 active
topics. I currently have an application that is over that limit and I am
also having problems on 2 out of 98 screen that I have in my refrigeration
plant. Those two screen poll data from 2 evap panels and 48 unit coolers.
The first machine in the RS485 network manages to update these two screens
but the second machine (hot backup) only updates about half of the data and
draws a blank on the balance.

I havent found a solution yet that wont involve some type of rewrite but I'm
looking.

anthony

----- Original Message -----
From: Tony Chambers <[email protected]>
Subject: COMM: Wonderware - NETDDE

> Hi List,
> Is anyone aware of any issues with respect to Wonderware and NetDDE.
Our site controls network, mostly Honeywell SCAN3000, with AB PLC's through
port servers, and Intouch Wonderware is having network problems. The network guys
 
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