Peter Placek

It all depends. We are developing OPC servers (and formerly DDE) for more then five years but the only thing I can say is that it depends on situation.

OPC is quicker than DDE in general (nothing to say about the reliability) but if there is possibility to send data in buffers, DDE might go first.

Even more important than DDE or OPC might be the protocol used:
RK512 - good for communication with more PLC's at a time as it is point-to-point
MPI - quicker, but only for communication with one PLC any Profibus - probably the fastest, but we do not have much experience with these protocols yet, but certainly it is the most
costly solution

Peter Placek.

Merz Company ...
Peter Placek, Sales and Marketing Manager
tel: +420 48 510 0272, fax: +420 48 510 0273