An industrial connectivity edge reference application translating from proprietary protocols to OPC UA leveraging the W3C Web of Things (WoT) thing descriptions via the new WoT-Connectivity specification. Thing Descriptions can be easily edited using the Eclipse Foundation's edi{TD}or.
UA Edge Translator solves the common "brownfield" use case of connecting disparate industrial assets with proprietary interfaces and translates their data into an OPC UA information model (ideally to one of the standardized companion specifications from the UA Cloud Library), enabling processing of the assets' data either on the edge or in the cloud leveraging a normalized, IEC standard (OPC UA) data format. This accelerates Industrial IoT projects and saves cost since the data doesn't need to be normalized in the cloud and makes use of the OT expertise often only found on-premises. For defining a mapping from the proprietary data format to OPC UA, the Web of Things (WoT) Thing Description schema (JSON-LD-based) is used. Additionally, the mechanism to provide the schema to the UA Edge Translator is also leveraging OPC UA. Therefore, for the first time, OPC UA is used for both the control and data plane for industrial connectivity, while previous solutions only used OPC UA for the data plane and a proprietary REST interface for the control plane.
UA Edge Translator is available as a pre-built Docker container and will run on any Docker- or Kubernetes-enabled edge device. See "Packages" in this repo for details.
UA Edge Translator supports provisioning via GDS Server Push functionality as described in part 12 of the OPC UA specification. Until an issuer certificate is provided in the issuer certificate store of UA Edge Translator, it is in provisioning mode and access to the WoT-Connectivity-related OPC UA nodes in its address space is restricted. An issuer certificate can be provided as part of the GDS Server Push mechanism or by manually copying a certificate into the issuer certificate store found in the /app/pki/issuer/certs directory. During provisioning, all client certificates are auto-approved by UA Edge Translator, but afterwards they need to be manually trusted by copying them from the rejected certificate store to the trusted certificate store, unless of course the certificates were already trusted (for example because they were provided by the GDS Server Push mechanism). These stores can also be found in the /app/pki/ folder.
UA Edge Translator can be controlled through the use of just 2 OPC UA methods readily available through the OPC UA server interface built in. The methods are:
- CreateAsset(assetName) - Creates an asset node and an OPC UA File API node below the asset node (which can be used to upload the WoT Thing Description), returning the node ID of the newly created asset node on success.
- DeleteAsset(assetNodeId) - deletes a configured asset.
In this reference implementation, Modbus TCP, OPC UA, Siemens S7Comm (experimental), Mitsubishi MC Protocol (experimental), Rockwell CIP-Ethernet/IP (experimental), and Beckhoff ADS (experimental) are supported. Other interfaces can easily be added by implementing the IAsset interface. There is also a tool provided that can convert from an OPC UA nodeset file (with instance variable nodes defined in it), an AutomationML file, a TwinCAT file, or an Asset Admin Shell file, to a WoT Thing Model file.
The following folders within the Docker container store logs, certificates, secrets and settings and should be mapped and persisted (-v argument in Docker command line) to the Docker host to encrypted folders, e.g. protected folders using BitLocker:
- /app/logs
- /app/settings
- /app/pki
E.g. -v c:/uaedgetranslator/pki:/app/pki, etc.
Client certificates need to be manually moved from the /pki/rejected/certs folder to the /pki/trusted/certs folder to trust an OPC UA client trying to connect.
OPCUA_USERNAME- OPC UA username to connect to UA Edge Translator.OPCUA_PASSWORD- OPC UA password to connect to UA Edge Translator.
LOG_FILE_PATH- path to the log file to use. Default is /logs/uaedgetranslator.logfile.txt (in the Docker container).APP_NAME- OPC UA application name to use. Default is UAEdgeTranslator.UACLURL- UA Cloud Library URL (e.g. https://uacloudlibrary.opcfoundation.org or https://cloudlib.cesmii.net).UACLUsername- UA Cloud Library Username.UACLPassword- UA Cloud Library Password.OPCUA_CLIENT_USERNAME- OPC UA client username to connect to an OPC UA asset.OPCUA_CLIENT_PASSWORD- OPC UA client password to connect to an OPC UA asset.