at the moment I write my diploma thesis. The purpose of this project is the development of a network of PLC control units with CORBA to realize easy maintainability and network connection. Such solutions are presently not very common and it's hard to get an overview about the existing technologies. In doing so my task is firstly to collect and evaluate the existing technologies, but i never find such applications.
Have someone from this forum ever heard about such software, ORBs, hardware? Or have someone a solution to solve my problem?
Try Borland C/C++ Builder or JBuilder. There are standard Corba objects with examples in this IDEs so You can easy implement CORBA in your application. For communication with PLC I suggest You use Modbus TCP/IP protocol.
To realize maintainability and network connectivity was also one of the tasks the opcfoundation.org had to address in 1996. In stead of using CORBA, it was decided to go with the Component Object Modeling standard (COM). As a result connectivity to the hardware (plc's loop controllers, io-cards) has standardized to OPC (Ole for Process Control aka Openess Productivity & Connectivity . OPC is based on the COM standard. You can look at an OPC Server as a little software component which on one side communicates to devices through some proprietary vendor dependant protocols and on the other side exposes a set of well documented (vendor independant) set of interfaces
So, probably the simplest answer to your task could be:
- find an OPC Server for your preferred PLC.
(e.g. from kepware.com, iconics.com, softwaretoolbox.com)
- interface CORBA with COM using either the
COM custom interfaces or the COM Automation Interfaces. (for details study opcfoundation.org or try some of the Visual Basic code provided with Kepware drivers)
Raymond van der Tas
I ran into this issue last year on a project where we needed to bridge MS technologies with J2EE (CORBA). Unfortunatly the project never got past the high-level design stage but after doing some research I found a couple of Java/COM/.NET bridge applications that might do the trick if you must use OPC/COM:
1. Intrinsyc's Integra http://ja.net.intrinsyc.com/
2. Janeva from Borland (.NET)
3. JNBridgePro from JNBridge
No matter what you chooose, bridging technologies will be complicated.
Ideally you can find an CORBA toolkit that you can build on top of a PLC driver but I've never found anything like that.
Hope the above helps.