Re: Simple Components 4.12 with MQTT implementation released

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 14/04/2016 23:30, slos wrote:

> Be prepared to ear about it soon.
> Just google for "industry 4.0 opc ua"

Well, actually I am involved in an Industry 4.0 project:

    http://www.secureplugandwork.de/servlet/is/10291/

We indeed use OPC UA in this project. But OPC UA is unsuitable for field 
automation, basically, for any work associated with data acquisition and 
control. Therefore the architecture is that the OPC UA is only a gateway 
to the applications. All actual the work is done by the middleware 
developed by cbb software GmbH running on the system nodes (ARM boards). 
The middleware feeds an UPC UA server which the gateway's OPC UA client 
accesses. BTW, the middleware is 100% Ada and 0% OPC.

Note that without OPC UA everything could work far better and require 
far less resources. E.g. having all process data the OPC cannot access 
because it is too slow to pace with the middleware capable to deliver 
data at less than 1ms rate and does not properly support 
push-subscriptions, does not support distributed time stamping, physical 
units, error states etc.

That was the reason why it was decided that the OPC UA gateway would not 
deal with process data at all. It is used only for configuration and 
possibly for history process data.

In short, there are serious multiple reasons why OPC UA cannot be used 
in the field, regardless how strong the push for it is.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de