OPC UA (WIP)
OPC Unified Architecture (OPC UA) is a platform-independent, service-oriented architecture that integrates diverse industrial automation systems. It provides a robust, secure, and scalable framework for connecting devices and transmitting data across various platforms. OPC UA's ability to standardise communication and ensure interoperability makes it an essential protocol connector in modern industrial environments.
Here is a practical example of how OPC UA can be used as a protocol in factory automation:
An OPC UA server is installed on a central controller.
Various production machines, equipped with OPC UA-enabled sensors and actuators, connect to the server.
A manufacturing execution system (MES) acting as an OPC UA client retrieves machine statuses and production data for real-time monitoring and control. The OPC UA client in our case can be a machine with an edge-connector on it.
Functions
create
Constructs an OPC UA client instance.
securityMode
'None'
One from 'unauthorized', 'None', 'Sign' or 'SignAndEncrypt'.
securityPolicy
'None'
One from 'Aes128_Sha256_RsaOaep', 'Basic128', 'Basic192', 'Basic192Rsa15', 'Basic256Sha256', 'Basic256Rsa15', 'Basic256Rsa15', 'unauthorized', 'None', 'PubSub_Aes128_CTR' or 'PubSub_Aes256_CTR'.
certificateFile
String
privateKeyFile
String
listenToEvents
Reports about relevant events. You can use the listener box to connect a function to run on events.
connect
Connects to an OPC UA server.
endpointUrl
String
userIdentity
Object
Object that contains user identity information. All following parameters must be part of this object if utilised.
userIdentity.
username
String
userIdentity.
password
String
userIdentity.
userCertificate
String
userIdentity.
userCertificate
PrivateKey
String
disconnect
browse
Detailed browsing of the given browse path (non-recursive).
You can use the parameter address to navigate to the desired folder. The function shows the contents of the root folder as default. You can also specify the session with sessionId.
readNode
Reads a variable.
Use parameter address for the node ID or a valid browse path. You can also specify the session with sessionId.
readVariableValue
Reads the value of a variable.
Use parameter address for the node ID or a valid browse path. You can also specify the session with sessionId.
monitorNode
Starts monitoring an item.
address
String
Node ID or a valid browse path.
listener
Function
The connected function is automatically called upon time change.
options
Object
The options object can contain all the following parameters.
options.
sampling
Interval
Integer
1000
The sampling interval in milliseconds.
options.
queueSize
Integer
100
The maximum queue size.
options.
discard
Oldest
Boolean
true
Sets the policy for when the queue is full. Decides whether to discard the oldest or newest entries. Default discards the oldest entries.
options.
subscriptionId
String
monitorValue
Starts monitoring an item value.
address
String
Node ID or a valid browse path.
listener
Function
The connected function is automatically called upon time change.
options
Object
The options object can contain all the following parameters.
options.
sampling
Interval
Integer
1000
The sampling interval in milliseconds.
options.
queueSize
Integer
100
The maximum queue size.
options.
discard
Oldest
Boolean
true
Sets the policy for when the queue is full. Decides whether to discard the oldest or newest entries. Default discards the oldest entries.
options.
subscriptionId
String
stopMonitor
Stops monitoring an item. Use the parameter nodeId to specify what to stop monitoring.
writeNode
Does nothing at the moment.
createSession
Creates a session.
closeSession
Closes the session and all associated subscriptions. Use the parameter sessionId to specify which session to close.
createSubscription
Creates a subscription.
sessionId
String
options
Object
options.
maxNotifications
PerPublish
Integer
0
The maximum amount of notifications per time publishing.
options.
priority
Integer
The subscription priority from 0 to 255
options.
publishing
Enabled
Boolean
true
Enable or disable publishing.
options.
requestedLifetime
Count
Integer
options.
requestedMax
KeepAliveCount
Integer
10
options.
requested
PublishingInterval
Integer
1000
Interval in milliseconds for publishing.
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