This is an OPC UA server running on the CAENels FAST-PS power supplies for remote control of the devices.
The sources can be obtained from the github repository git clone https://github.com/lehnertu/CAENels-FastPS-OPCUA.git
The server is based on the Open62541 open source implementation of OPC UA.
- Provides an OPC-UA server at TCP/IP port 16664.
- A server responding to UDP packets is listening at port 16665.
- Access to device data is handled via the provided TCP server (port 10001).
- Server configuration is loadad from file /etc/opcua.xml
All functionality necessary to user the supllies to power corrector coils in an accelerator control system environment is provided via OPC UA. This does not cover the whole functionality provided by the devices, only the essentials.
For faster control loops an additional UDP server was implemented which eliminates the protocol overhead associated with OPC UA.
The server receives packets with the following content:
- UInt32 : signature word 0x4C556543 which is checked for the packet to be accepted
- UInt32 : must be different from 0 to indicate that setpoints should be modified
- Int64 : current setpoint in uA
- Int64 : voltage setpoint in uV
Every received packet showing the correct signature is answered with another packet showing:
- UInt32 : device status word
- Int64 : current setpoint in uA
- Int64 : voltage setpoint in uV
- Int64 : current readback in uA
- Int64 : voltage readback in uV
The server compiles and runs stabily on all power supplies used for the tests.
TODO:
- update to Open62541 V1.0
- reasonable error handling
- wait until TCP server becomes available, don't die immediately
- mreset should always read false
The server is built with a cross-compiler running on a Linux system for the ARM target CPU of the power supplies.
The OPC UA stack needs to be downloaded and built. This can be done on the development system - there is no binary code produced at this stage. The complete stack is obtained in two (amalgamated) files.
- open62541.h
- open62541.c
In addition the libxml2 library is required. It needs to be built and installed into the cross-target tool chain.
A makefile is not yet provided, just a few lines are required to build the server.
- source ../tools/environment
- $CC -std=c99 -c open62541.c
- $CC -std=c99 -c -I $SDKTARGETSYSROOT/usr/include/libxml2/ OpcUaServer.c
- $CXX -o opcuaserver OpcUaServer.o open62541.o -lpthread -lxml2
if dynamic linking is used a compatible version of libxml2.so has to be installed onto the target alternative static linking of xml library $CXX -o opcuaserver OpcUaServer.o open62541.o $SDKTARGETSYSROOT/usr/lib/libxml2.a -lpthread
For istallation a few files need to be copied onto the device:
- opcuaserver binary installed in /tmp/ for testing
- opcua.xml configuration file in /etc/
- libxml2.so.2 in /usr/lib/ (if not static link)
The server can then be run by executing /tmp/opcuaserver.
For an automatic start at bootup the startup script has to be installed as follows: $ scp opcua-startup root@10.66.67.10:/etc/init.d/ A link has to be set in the startup script directory: $ ssh root@10.66.67.10 $ cd /etc/rc5.d/ $ ln -s ../init.d/opcua-startup S99z-opcua-startup
For a first test of the server an universal OPC UA client like UaExpert is recommended.
A LabView client demonstrating the access using OPC UA is provided in the examples/ folder.