OPC UA Plugin

The OPC UA plugin integrates two OPC UA specifications: Data Access and Alarms and Conditions.
Configuration location:
Console Application
Service Application
[Edge Main Folder]/configs/configurations/InputPlugins/OPCUA
These configs are only used for the Edge instance Luna.Console, executed directly from the [Edge Main Folder]. Click the "Service Application" tab above to check the location for Edge services.
C:/ProgramData/Senseforce/Luna Data/[YourServiceName]/configurations/InputPlugins/OPCUA
You can install several SF Edge service instances onto one device - for example to collect data of several machines from a local data collection device. Each service instance needs it's own set of configurations. When using the Senseforce Edge Service Installer, the default configurations are automatically installed for any service.
Use the default DataMappings.xml and opcapplicationconfiguration.xml for most use cases. The default DataMappings.xml generate the following OPC UA Data Variables which can be used in the EventDefinition.xml
  • DisplayName: Name of the OPC UA item
  • SubscriptionName: Name of the OPC UA subscription, the item was assigned to
  • StatusCode: OPC UA Status Code of the item
  • Data: Data value of the OPC UA item
  • DataType: Translated data-type of the OPC UA item (.net datatype, not opc ua type)
  • SourceTimestamp: Timestamp when the source notified a change in value
  • ServerTimestamp: Timestamp when the Server recognized the change in value
  • StartNodeId: Node-Id of the item
If using the OPC UA Aggregations:
  • [DisplayName]Average, [DisplayName]Maximum, [DisplayName]Minimum, [DisplayName]StandardDeviation: If using the OPC UA Aggregation feature, these data points are moving aggregations according to the aggregation configuration. The DisplayName of the item is prepended to the aggregation type.


The OpcUaSettings.xml contains general information required for both Data Access as well as Alarms and Conditions.

Example configuration

Name of the OPC UA session. Just for informational purposes
Defines where to find the OPC UA server. Use the fully qualified OPC UA server endpoint URL
<?xml version="1.0" encoding="utf-8" ?>
<OpcUaConfiguration xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://senseforce.io/ ..\..\Schemas\opcuasettings.xsd">
<SessionName>Senseforce Luna OPC UA Client</SessionName>
<!-- Defines the maximum security level to connect with -->
<!-- Regex which is used to extract variable name from StartNodeId -->
<!-- <VariableNameRegex> myregex </VariableNameRegex> -->
<!-- Regex which is used to extract a new Datapoint called NodeIdRegex
The NodeId is used to create the value by specifying a regex. -->
<!-- <NodeIdRegex> myRegex </NodeIdRegex> -->
<!-- Set path and file name of the opc application configuration file -->
<!-- Set path and file name of the opc subscriptions configuration file -->
<!-- Set path and file name of the opc mapping file -->
<!--LogLevel: Debug,Information,Warning,Error,Critical,None-->

Advanced settings

By default SF Edge uses the maximum security mode available at the OPC UA server. Optionally degrade the security setting. Allowed values: SignAndEncrypt, Sign, None
Username / Password
Optional user credentials for authenticating SF Edge at the server
Optional. If subscriptions to textual nodes are established, use this setting to set which localization should be used.
Timeout of the OPC UA session.
Regex which is used to extract variable name from OPC UA server's StartNodeId
Regex, used to create a new datapoint called NodeIdRegex. The OPC UA server NodeId is used to create the value by matching this regex.

OPC UA Certificate handling

To establish a secure connection between SF Edge and the OPC UA server, the SF Edge certificates as well as the OPC UA server certificate need to be exchanged
  1. 1.
    Copy public Senseforce Edge certificate (the public .der -file in the certs/certs - folder) to the OPC UA Server's trusted certificate folder
    1. 1.
      Default OPC UA server trusted certificate folder is in [CommonApplicationData]/OPC Foundation/CertificateStores/UA Applications/certs (on the OPC UA server computer)
      1. 1.
        CommonApplicationData for Windows: C:/ProgramData
      2. 2.
        CommonApplicationData for unix: /usr/share (or the assemblies runtime location)
  2. 2.
    Copy the the OPC UA Server certificate to the SF EOPC UA trusted certificate folder. (Configured in the SF Edge opcapplicationconfiguration.xml file)
    1. 1.
      Default folder: CommonApplicationData/OPC Foundation/CertificateStores/UA Applications/certs
    2. 2.
      Default behavior to get the server certificate:
      1. 1.
        Start SF Edge with OPC UA Plugin (and therefore try to connect to the server)
      2. 2.
        SF Edge will automatically place the server certificate in the rejected certificates folder (configured in the SF Edge opcapplicationconfiguration.xml file - default: [CommonApplicationData]/OPC Foundation/CertificateStores/RejectedCertificates/certs).
      3. 3.
        Manually copy the server certificate from Rejected to Trusted folder

Subscription creation

To finally connect to the OPC UA server and subscribe to server nodes, the opcuasubscriptions.xml file needs to be configured. Use the Senseforce OPC UA server browser to create subscriptions for either OPC UA Data Access or Alarms and Conditions.
Exemplary opcuasubscriptions.xml are found below

Data Access

The belows example subscription subscribes to two Monitored items by defining two MonitoredItem blocks (see line 29 to 44 and 45 to 60). The most relevant settings are:
Identifier (line 32)
Defines the OPC UA node address - to be found in the OPC UA Server definition or by using a OPC UA Data Access client.
SamplingInterval (line 40)
Set the server-side sampling interval of the data point. Set to 0 for "as fast as possible" or -1 for "as fast as publishing interval". In milliseconds.
To add another node id to the subscription, simply copy/paste a full MonitoredItem (eg. lines 29 to 44) and change the Identifier as described above.
<?xml version="1.0" encoding="utf-8"?>
<ListOfSubscription xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://opcfoundation.org/UA/2008/02/Types.xsd">
<StartNodeId i:nil="true" />
<RelativePath i:nil="true" />
<IndexRange i:nil="true" />
<Encoding i:nil="true" />
<Filter i:nil="true" />
<RelativePath i:nil="true" />
<IndexRange i:nil="true" />
<Encoding i:nil="true" />
<Filter i:nil="true" />
<RelativePath i:nil="true" />
<IndexRange i:nil="true" />
<Encoding i:nil="true" />
<Filter i:nil="true" />

Setting OPC UA hysteresis filters

OPC UA implements powerful hysteresis filter settings. To add a filter to a specific monitored item, simply replace the section "<Filter i:nil="true" />" with
<Filter i:type="DataChangeFilter">
any absolute hysteresis value (eg. changing DeadbandValue to 10 means only values which changed by at least 10 compared to previous values are recognized)

Alarms and Conditions

Use the Senseforce OPC UA Data Access browser to create an opcuasubscriptions.xml file. Replace the original file with the newly created one.


Use the Aggregations.xml file to define moving aggregations for one or several of your variables.
<?xml version="1.0" encoding="utf-8" ?>
<AggregationConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<!-- DataPointName must match a StartNode-Identifier of a monitored item
see the subscription.xml for node-identifiers-->
<!-- Allowed types are: Average, StandardDeviation, Maximum, Minimum-->
<!-- Defines the size of the moving aggregation window. -->
Use one AggregatedValue Block per variable you want to aggregate. Add the following settings to each block:
Name of the OPC UA item to aggregate. Note: The name identifies the Node-Identifier of a monitored item, not the DisplayName. Refer to your subscription.xml to check your NodeIdentifiers.
(Annotation: If you have an Identifier like ns=2;i=10854, the Node-Identifier and therefore DataPointNmae is 10854!
Add one <Type></Type> line for each aggregation type you want to configure. Allowed types are Average, StandardDeviation, Maximumand Minimum.
You can define several types for one variable (but only one for each type of aggregation).
The aggregations are implemented using moving statistics - meaning, always a moving window of aggregations is calculated. The WindowSizeNumber defines how many samples are used for one aggregation cycle. Refer to the SamplingInterval setting in your subscription.xml (see section Subscription creation)