mod_openopc was developed under Fedora Core 7 [Moonshine], and was intended to
be run upon a Linux 2.6 or laterkernel based Operating System. OpenOPC.
Matrikon has documents on their web site explaining how to configure DCOM to make
remote OPC connections work. In reality it can be quite complicated to get remote
OPC connections working. This is certainly true for Windows XP SP2 where additional
security settings further complicates the configuration.
An Open Source software project called OpenOPC tries to change this. With OpenOpc
you can access OPC servers from other platforms. OpenOpc also gives you the possibility
to bypass DCOM security by installing a service that allows remote TCP/IP
connections requesting OPC data. The Gateway service will typically be installed on
the same machine where the OPC server is installed, making it much simpler to ensure
the Gateway service has the correct permissions allowing it to connect to the OPC
server. The Gateway service is also used by non-Windows operating systems that do
not support DCOM.
mod_openopc is a cross platform utility/package that has the following goals:
- function primarily in a Linux kernel 2.6 or greater environment and any other UNIX or
UNIX-Like Operating System.
While it has been shown that performance is poor in MS-Windows (21 times slower than in Linux).
Strictly speaking though, mod_openopc is to run on any OS which can support Python and MySQL.
- serve as a 'front end' for 'Open OPC for Python', thereby turning that
library's more complex functions into very simple tasks (add transparency for the end user).
- serve as a central point of contact for the following discrete items, and
OPC Servers running Open OPC Gateway
MySQL Servers and Databases
Web pages issuing write commands to OPC Devices
Any other 3rd party program or device which issues a write command to an OPC Device
- function as a bridge between two OPC Devices on the same OPC server or a different OPC servers. For
example, an OPC Device on Ethernet may not typically be able to communicate
with an OPC Device on Allen Bradley's Data Highway Plus network (without
expensive proprietary hardware and program modifications). mod_openopc shall
enable fast (relative) read and writes between these devices (messaging).
XML/DA client |
Java clients |
DCOM implement |
Intermediate SW/HW solution |
UA-COM wrappers |
Links and tools