Companion specifications complement OPC UA with the goal of fostering interoperability. This article will provide an overview about implementing a Companion Specification with open62541.
So far programs using Qt OPC UA with the open62541 back-end produced quite a bit of chatter on stdout originating from the open62541 stack itself. Unfortunately there was no simple way to get rid of these low-level logs. We now provide a way to control this behavior.
Something that has traditionally been complicated to achieve in Qt/QML, especially on low end hardware, is high performant list scrolling with complex delegates.
This has recently changed. In Qt 5.15, it is as simple as setting the new QML ListView property called reuseItems to true. For more details, have a look at the documentation.
In this blog post, I will explain how you can implement this feature in Qt Versions prior to 5.15.
The Qt OPC UA module has been ported to CMake and will be part of Qt 6 right from the first release.
In addition to numerous bug fixes and improved test coverage, the open62541 plugin has been updated to open62541 v1.1 and uses OpenSSL for security support, thus removing the dependency on mbedTLS.
basysKom recently extended this plugin to also accept PEM-based input. PEM is a file format used for certificates and keys which is specified by an RFC and is a preferred format for a lot of open source software. The pull request has been merged and our contribution is available from the 1.1 branch (and will also hit the master branch soon).
The open62541 OPC UA stack with its Pub-Sub extension now supports MQTT over TLS as well as MQTT-brokers requiring a login (contributed by basysKom). This allows the direct communication between open62541 and the Azure IoT Hub and therefore highly simplifies the connection of OPC UA based IoT Devices to the cloud.