Whats bothering me...n the world is not bothered about !!!

 

Its Global Warming !!!!!!!!!!!!

India's sea levels are increasing....n imagine what???

OPC UA

Existing OPC Model is dropped for below reasons

COM/DCOM security vulnerability
Intra- corporate network operational issues
Too many protocols, some work together..some doesn’t



New Model - UA
Support for existing model
User webservices to communicate
Ease of communication,easy configuration
Optimized for internet - OPC binary encoding over TCP ???
Subscription Update Features
Keep-alive (heartbeat) messages
Allows clients to detect a failed server or channel ???
Sequence Numbers in each update message
Allows client re-sync to obtain missed messages
Decouples callback channel from notification mechanism, allowing callback channel to be reset without loss of data ???
Security
UA Clients present credentials to UA Servers (x509 certs on both sides).
UA Servers require authentication and authorization.
Access control can be fine-grained down to the property level.
Optional message signing and encryption.
How is enterprise integration done ???
communication architecture: 3 layers: protocol, proxy/stub, API (.NET)
fully based on public specifications (WSDL, SOAP, WS*)
o platform independent
o well supported with the next .NET version
efficient enough to replace DCOM
Scalable
Standard internet protocols allow cross-platform communication
Multiple UA APIs
C/C++
JAVA
Microsoft .NET

Protocols
As described before there are two protocols. An application programmer will recognize this only via the different URL he has to pass for binary protocol opc.tcp://Server and http://Server for WebService. Otherwise OPC UA works completely transparent to the API.

1. Binary protocol
best performance, the least overhead
takes minimum resources (no XML Parser, SOAP and HTTP required -> important for embedded devices)
best possible interoperability (binary is explicitly specified and allows less degrees of freedom during implementation as XML does)
only one single TCP port (4840) gets used for communication and can get tunneled or enabled through a Firewall easily
2. WebService (SOAP)
best supported from available tools. It can be easily used i.e. from JAVA or .Net environments
Firewall-friendly. Port 80 (http) and 443 (https) will usually work without additional configuration.


Can binary protocol interop with wenservice protocol???


Specifications:




Services:
OPC UA Defines 34 services
SecureChannelService Set
Session Service Set
Node Management Service Set
View Service Set
Query Service Set
Attribute Service Set
Method Service Set
Subscription Service Set
Monitored Item Service Set


The first thing to note is that OPC DA is here to stay. Is your existing OPC DA server delivering the data you need to your HMI/SCADA system the way you need it to? Then it's not obsolete. As shown in Fig. 1, OPC UA in large part seeks to address the issues of sharing information in more complex data structure formats with enterprise level MES and ERP systems in a way that they can understand. OPC UA does this by providing the means to handle complex data structures and transport them in a secure, reliable, service oriented architecture (SOA). But the data from the plant floor devices still has to come from somewhere. That 'somewhere' is for now OPC DA servers and will remain the status quo because of the large installed base of OPC DA servers.
Are all UA Specs out??? Well defined ?? Like UA 1, UA2 etc
What is the current development going on at OPCF on UA?
What is binary coding to increase performance via WS