The OPC UA adapter functions as an OPC UA client and allows an IoT gateway (or any other client) to interact with an OPC UA server.
Communication with the OPC UA adapter is enabled through MQTT and the configuration collections detailed below.
Currently, the adapter supports OPC UA read and write, with more options to follow.
The OPC UA adapter was constructed to communicate with a system defined in a ClearBlade Platform instance. Therefore, the adapter requires a system to have been created within a ClearBlade Platform instance.
Once a system has been created, artifacts must be defined within the ClearBlade Platform system to allow the adapter to function properly. At a minimum:
- An adapter configuration data collection named
adapter_configneeds to be created in the ClearBlade Platform system and populated with data appropriate to the Modbus client adapter. The data collection schema should be as follows:
| Column name | Column datatype |
|---|---|
| adapter_name | string |
| adapter_settings | string |
| topic_root | string |
The adapter_settings JSON string provided in the adapter_config collection is expected to have the following structure. This JSON is how you provide the adapter with the specific OPC UA server connection details.
{
"endpoint_url": "opc.tcp://clearblades-mbp.lan:53530/OPCUA/SimulationServer",
"authentication": {
"type": "username",
"username": "testing",
"password": "testing"
},
"security_mode": "signandencrypt",
"security_policy": "Basic256"
}| Authentication type | Details |
|---|---|
Anonymous |
Use anonymous authentication; no other fields are required in the authentication object |
Username |
Use username and password authentication, must include username and password key/values in the authentication object |
Certificate |
Not yet implemented |
| Security mode |
|---|
None |
Sign |
SignAndEncrypt |
| Security mode |
|---|
none |
Basic256 |
Basic256SHA256 |
| Operations |
|---|
read |
write |
method |
subscribe |
The OPC UA adapter will subscribe to specific topics to handle OPC UA operations. Additionally, the adapter will publish messages to MQTT topics for the OPC UA operation results. The topic structures utilized are as follows:
- OPC UA read request: {TOPIC ROOT}/read
- OPC UA read results: {TOPIC ROOT}/read/response
- OPC UA write request: {TOPIC ROOT}/write
- OPC UA write response: {TOPIC ROOT}/write/response
- OPC UA method request: {TOPIC ROOT}/method
- OPC UA method response: {TOPIC ROOT}/method/response
- OPC UA subscribe request: {TOPIC ROOT}/subscribe ** create, publish, and delete are the only supported services in the OPC UA library being utilized
- OPC UA subscribe response: {TOPIC ROOT}/subscribe/response
- OPC UA publish: {TOPIC ROOT}/publish/response
- OPC UA browse request: {TOPIC_ROOT}/browse/_edge/{EDGE_ID}
- OPC UA browse results: {TOPIC_ROOT}/browse/response
- OPC UA connect request: {TOPIC_ROOT}/connect/_edge/{EDGE_ID}
- OPC UA connect results: {TOPIC_ROOT}/connect/response
{
"node_ids": [
"ns=3;i=1001",
"ns=3;i=1002",
"ns=3;i=1003",
"ns=3;i=1004",
"ns=3;i=1005",
"ns=3;i=1006"
]
}{
"server_timestamp": "2021-07-30T05:04:55Z",
"data": {
"ns=3;i=1001": {
"value": 6,
"source_timestamp": "2021-07-30T05:04:55Z"
},
"ns=3;i=1002": {
"value": -1.698198,
"source_timestamp": "2021-07-30T05:04:55Z"
},
"ns=3;i=1003": {
"value": -2,
"source_timestamp": "2021-07-30T05:04:55Z"
},
"ns=3;i=1004": {
"value": -1.732051,
"source_timestamp": "2021-07-30T05:04:55Z"
},
"ns=3;i=1005": {
"value": -2,
"source_timestamp": "2021-07-30T05:04:55Z"
},
"ns=3;i=1006": {
"value": -1.333333,
"source_timestamp": "2021-07-30T05:04:55Z"
}
},
"success": true,
"status_code": 0,
"error_message": ""
}{
"node_id": "ns=3;i=1001",
"value": 25 // can be string or int/float
}{
"node_id": "ns=3;i=1001",
"timestamp": "", //ISO formatted timestamp
"success": true|false,
"status_code": 0, //Integer
"error_message": ""
}{
"object_id": "ns=3;i=1001",
"method_id": "",
"arguments": [
{
"type": "uint32", // boolean, int16, uint16, int32, uint32, int64, uint64, float, double, string, node
"value": 5
},
{
"type": "node", // note that node type has a custom value structure to allow you to specify different node types
"value": {
"namespace": 0,
"identifier_type": "numeric", //also can be string
"identifier": 85
}
}
] //Array of arguments (with types)
}{
"object_id": "ns=3;i=1001",
"method_id": 25,
"timestamp": "", //ISO formatted timestamp
"success": true|false,
"status_code": 0, //Integer
"error_message": "",
"arguments": [],
"values": []
}{
"request_type": "create|republish|delete",
"request_params": {
//One of the following: (see below for schema)
//
//OPC UA subscription create request
//OPC UA subscription delete request
//OPC UA subscription republish request
}
}{
"publish_interval": 1000,
"lifetime": 25,
"keepalive": "", //ISO formatted timestamp
"max_publish_notifications": true|false,
"priority": 0, //Integer
"items_to_monitor": [
{
"node_id": "ns=2;i=1001",
"events": true|false,
"values": true|false
},
{
"node_id": "ns=3;i=1001",
"events": true|false,
"values": true|false
},
...
],
}- The events flag in each item_to_monitor indicates whether or not events should be subscribed to
- The value flag in each item_to_monitor indicates whether or not value changes should be subscribed to
{
"subscription_id": {the_subscription_id}, //INTEGER
}{
"request_type": "create|publish|delete",
"timestamp": "", //ISO formatted timestamp
"success": true|false,
"status_code": 0, //Integer
"error_message": "",
"results": [ //Will only contain data when request_type = "publish"
{
"node_id": "ns=2;i=1001",
"client_handle": 1,
"value": 5,
"event" : {
"event_id": "",
"event_type": "SystemEventType",
"severity": 2, //1-1000
"time": "", //ISO formatted timestamp
"message": "A system event has occurred",
}
},
{
"node_id": "ns=3;i=1001",
"client_handle": 2,
"value": "hello",
"event" : {
"event_id": "",
"event_type": "SystemEventType",
"severity": 2, //1-1000
"time": "", //ISO formatted timestamp
"message": "A system event has occurred",
}
},
...
],
}{
"root_node": "ns=2;s=Dynamic" //the root node, STRING
}{
"node_ids": [
"ns=2;s=Dynamic/RandomInt32",
"ns=2;s=Dynamic/RandomInt64",
"ns=2;s=Dynamic/RandomFloat",
"ns=2;s=Dynamic/RandomDouble"
],
"connection_status": {
"timestamp": "2021-11-16T17:18:02Z",
"status": "BrowseSuccess", //BrowseSuccess, BrowseFailed, or BrowsePending
"error_message": "" //will not be returned if empty
}
}{
"root_node": "ns=2;s=Dynamic", //the root node, STRING (optional)
"level_limit": 10, //Limit the depth of the search (optional)
"node_list": [
{
"node_name": "RandomDouble",
"path": "ns=2;s=Dynamic.ns=2;s=Dynamic/RandomDouble"
},
{
"node_name": "RandomInt64",
"path": "ns=2;s=Dynamic.ns=2;s=Dynamic/RandomInt64"
}
],
"attributes": [
"NodeClass",
"BrowseName",
"Description",
"AccessLevel"
"DataType",
"DisplayName",
] //node attributes array to return (all supported shown)
}{
"nodes": [
{
"node_id": "ns=2;s=Dynamic/RandomInt64",
"parent_node_id": "ns=2;s=Dynamic",
"node_class": "NodeClassVariable",
"browse_name": "RandomInt64",
"data_type": "i=8"
},
{
"node_id": "ns=2;s=Dynamic/RandomDouble",
"parent_node_id": "ns=2;s=Dynamic",
"node_class": "NodeClassVariable",
"browse_name": "RandomDouble",
"data_type": "float64"
}
],
"node_list": [
{
"node_name": "RandomDouble",
"path": "ns=2;s=Dynamic.ns=2;s=Dynamic/RandomDouble"
},
{
"node_name": "RandomInt64",
"path": "ns=2;s=Dynamic.ns=2;s=Dynamic/RandomInt64"
}
],
"connection_status": {
"timestamp": "2021-11-16T17:18:02Z",
"status": "BrowseSuccess", //BrowseSuccess, BrowseFailed, or BrowsePending
"error_message": "" //will not be returned if empty
}
}{
"root_node": "i=85", //the root node, STRING (optional)
"node_list": [
{
"node_name": "Real-Time",
"path": "AggregationServer.AggregatedServers.bhi-acquisition.Objects.Real-Time"
},
{
"node_name": "PredictedTrajectoryStations",
"path": "AggregationServer.AggregatedServers.bhi-atdprocessing.Objects.ServiceApplication.PredictedTrajectoryStations"
},
{
"node_name": "InputData",
"path": "AggregationServer.AggregatedServers.bhi-atdprocessing.objects.automatedtrajectorydrilling.service monitoring.InputData"
}
]
}{
"nodes": [
{
"node_id": "ns=51;i=5006",
"node_name": "Real-Time",
"path": "AggregationServer.AggregatedServers.bhi-acquisition.Objects.Real-Time"
},
{
"node_id": "ns=27;i=5015",
"node_name": "PredictedTrajectoryStations",
"path": "AggregationServer.AggregatedServers.bhi-atdprocessing.Objects.ServiceApplication.PredictedTrajectoryStations"
},
{
"node_id": "ns=27;i=5006",
"node_name": "InputData",
"path": "AggregationServer.AggregatedServers.bhi-atdprocessing.objects.automatedtrajectorydrilling.service monitoring.InputData"
}
],
"connection_status": {
"status": "BrowseSuccess",
"timestamp": "2022-10-07T06:21:44Z"
}
}{
//nothing! (empty message will suffice)
}{
"connection_status": {
"timestamp": "2021-11-16T17:18:02Z",
"status": "ConnectionSuccess", //ConnectionSuccess, ConnectionFailed, or ConnectionPending
"error_message": "" //will not be returned if empty
}
}{
"source_down": false,
"network_down": false,
"invalid_sessionkey": false,
"message": ""
}This adapter is built using the adapter-go-library, allowing multiple options for starting the adapter, including CLI flags and environment variables. Using a device service account for authentication with this adapter is recommended. See the below chart for available start options and their defaults.
All ClearBlade adapters require a certain set of system specific variables to start and connect with the ClearBlade Platform/Edge. This library allows these to be passed in by command line arguments or environment variables. Command line arguments take precedence over environment variables.
| Name | CLI flag | Environment variable | Default |
|---|---|---|---|
| System Key | systemKey |
CB_SYSTEM_KEY |
N/A |
| System Secret | systemSecret |
CB_SYSTEM_SECRET |
N/A |
| Platform/Edge URL | platformURL |
N/A | http://localhost:9000 |
| Platform/Edge Messaging URL | messagingURL |
N/A | localhost:1883 |
| Device Name (depreciated) | deviceName |
N/A | adapterName provided when calling adapter_library.ParseArguments |
| Device Password/Active Key (depreciated) | password |
N/A | N/A |
| Device Service Account | N/A | CB_SERVICE_ACCOUNT |
N/A |
| Device Service Account Token | N/A | CB_SERVICE_ACCOUNT_TOKEN |
N/A |
| Log Level | logLevel |
N/A | info |
| Adapter Config Collection Name | adapterConfigCollection |
N/A | adapter_config |
opc-ua-go-adapter -systemKey=<SYSTEM_KEY> -systemSecret=<SYSTEM_SECRET> -platformURL=<PLATFORM_URL> -messagingURL=<MESSAGING_URL> -deviceName=<DEVICE_NAME> -password=<DEVICE_ACTIVE_KEY> -adapterConfigCollection=<COLLECTION_NAME> -logLevel=<LOG_LEVEL>
A system key and system secret will always be required to start the adapter, and it's recommended to always use a device service account and token for adapters.
Device name and password for adapters are depreciated and only provided for backward compatibility and should not be used for any new adapters.
The OPC UA Go adapter depends on the ClearBlade Go SDK and its dependent libraries being installed. The OPC UA Go adapter was written in Go and therefore requires Go to be installed (https://golang.org/doc/install).
To compile the adapter for execution, the following steps need to be performed:
- Retrieve the adapter source code
git clone [email protected]:ClearBlade/opc-ua-go-adapter.git
- Navigate to the opc-ua-go-adapter directory
cd opc-ua-go-adapter
- Compile the adapter for your needed architecture and OS
GOARCH=arm GOARM=5 GOOS=linux go build