问题描述
我正在使用 GOPCUA v0.2.0-rc2 库连接到 OPC UA 服务器。如果我不在监控项中使用任何过滤器，一切正常。但我想使用 datachange 过滤器才能接收值，只有当它们改变某个百分比或绝对值时。以下是完整代码。
package main
import (
"context"
"flag"
"fmt"
"log"
"time"
"github.com/gopcua/opcua"
"github.com/gopcua/opcua/debug"
"github.com/gopcua/opcua/ua"
)
func main() {
var (
endpoint = flag.String("endpoint","opc.tcp://192.168.189.1:49320","OPC UA Endpoint URL")
policy = flag.String("policy","None","Security policy: None,Basic128Rsa15,Basic256,Basic256Sha256. Default: None")
mode = flag.String("mode","Security mode: None,Sign,SignAndEncrypt. Default: None")
certFile = flag.String("cert","","Path to cert.pem. required for security mode/policy != None")
keyFile = flag.String("key","Path to private key.pem. required for security mode/policy != None")
nodeID = flag.String("node","ns=2;s=HONDA.DEV1.T1","node id to subscribe to")
interval = flag.String("interval",opcua.DefaultSubscriptionInterval.String(),"subscription interval")
)
flag.BoolVar(&debug.Enable,"debug",false,"enable debug logging")
flag.Parse()
log.SetFlags(0)
subInterval,err := time.ParseDuration(*interval)
if err != nil {
log.Fatal(err)
}
// add an arbitrary timeout to demonstrate how to stop a subscription
// with a context.
d := 10 * time.Second
ctx,cancel := context.WithTimeout(context.Background(),d)
defer cancel()
endpoints,err := opcua.GetEndpoints(ctx,*endpoint)
if err != nil {
log.Fatal(err)
}
ep := opcua.SelectEndpoint(endpoints,*policy,ua.MessageSecurityModeFromString(*mode))
if ep == nil {
log.Fatal("Failed to find suitable endpoint")
}
fmt.Println("*",ep.SecurityPolicyURI,ep.SecurityMode)
opts := []opcua.Option{
opcua.SecurityPolicy(*policy),opcua.SecurityModeString(*mode),opcua.CertificateFile(*certFile),opcua.PrivateKeyFile(*keyFile),opcua.AuthAnonymous(),opcua.SecurityFromEndpoint(ep,ua.UserTokenTypeAnonymous),}
c := opcua.NewClient(ep.EndpointURL,opts...)
if err := c.Connect(ctx); err != nil {
log.Fatal(err)
}
defer c.Close()
notifyCh := make(chan *opcua.PublishNotificationData)
sub,err := c.Subscribe(&opcua.SubscriptionParameters{
Interval: subInterval,},notifyCh)
if err != nil {
log.Fatal(err)
}
defer sub.Cancel()
log.Printf("Created subscription with id %v",sub.SubscriptionID)
id,err := ua.ParseNodeID(*nodeID)
if err != nil {
log.Fatal(err)
}
var miCreateRequest *ua.MonitoredItemCreateRequest
var eventFieldNames []string
miCreateRequest = valueRequest(id)
res,err := sub.Monitor(ua.TimestampsToReturnBoth,miCreateRequest)
if err != nil || res.Results[0].StatusCode != ua.StatusOK {
log.Fatal(err)
}
// read from subscription's notification channel until ctx is cancelled
for {
select {
case <-ctx.Done():
return
case res := <-notifyCh:
if res.Error != nil {
log.Print(res.Error)
continue
}
switch x := res.Value.(type) {
case *ua.DataChangeNotification:
for _,item := range x.MonitoredItems {
data := item.Value.Value.Value()
log.Printf("MonitoredItem with client handle %v = %v",item.ClientHandle,data)
}
case *ua.EventNotificationList:
for _,item := range x.Events {
log.Printf("Event for client handle: %v\n",item.ClientHandle)
for i,field := range item.EventFields {
log.Printf("%v: %v of Type: %T",eventFieldNames[i],field.Value(),field.Value())
}
log.Println()
}
default:
log.Printf("what's this publish result? %T",res.Value)
}
}
}
}
func valueRequest(nodeID *ua.NodeID) *ua.MonitoredItemCreateRequest {
handle := uint32(42)
attributeID := ua.AttributeIDValue
filter := ua.DataChangeFilter{}
filter.Trigger = ua.DataChangeTriggerStatusValue
filter.DeadbandType = uint32(ua.DeadbandTypeNone)
filter.DeadbandValue = 0.0
filterExtObj := ua.ExtensionObject{
EncodingMask: ua.ExtensionObjectBinary,TypeID: &ua.ExpandednodeID{
NodeID: nodeID,Value: filter,}
request := &ua.MonitoredItemCreateRequest{
ItemToMonitor: &ua.ReadValueID{
NodeID: nodeID,AttributeID: attributeID,DataEncoding: &ua.Qualifiedname{},MonitoringMode: ua.MonitoringModeReporting,RequestedParameters: &ua.MonitoringParameters{
ClientHandle: handle,discardOldest: true,Filter: &filterExtObj,QueueSize: 10,SamplingInterval: 0.0,}
return request
}
发送监控请求时，出现以下错误。
服务器不支持请求的监控项过滤器。 StatusBadMonitoredItemFilterUnsupported (0x80440000)
服务器为Kepware OPC UA服务器，服务器端的日志如下，
服务器收到的请求
4/15/2021 5:24:07.474 PM [gopcua-1618489446170158449] CreateMonitoredItemsRequest
0000000000: Event started
0000000000: Request Header:
0000000000: authenticationToken: i=2991937600
0000000000: timestamp (UTC): 2021-04-15T12:24:06.180
0000000000: requestHandle: 5
0000000000: returnDiagnostics: 0
0000000000: auditEntryId: [empty]
0000000000: timeoutHint(ms): 10000
0000000000: Parameters:
0000000000: subscriptionId: 16
0000000000: timestampsToReturn: Both
0000000000: monitoredItemCreateRequests []: Size: 1
0000000000: monitoredItemCreateRequests [ 0 ]:
0000000000: itemToMonitor:
0000000000: nodeId: ns=2;s=HONDA.DEV1.T1
0000000000: attributeId: Value
0000000000: indexrange: [empty]
0000000000: dataEncoding: [empty]
0000000000: monitoringMode: Reporting
0000000000: requestedParameters:
0000000000: clientHandle: 42
0000000000: samplingInterval: 0
0000000000: filter:
0000000000: parameterTypeId: 67800040
0000000000: queueSize: 10
0000000000: discardOldest: 1
0000000000: Event complete
服务器发送的响应。
4/15/2021 5:24:07.474 PM [gopcua-1618489446170158449] CreateMonitoredItemsResponse
0000000000: Event started
0000000000: Response Header:
0000000000: timestamp (UTC): 2021-04-15T12:24:07.474
0000000000: requestHandle: 5
0000000000: serviceResult: 0x00000000 (Good)
0000000000: Parameters:
0000000000: monitoredItemCreateResults []: Size: 1
0000000000: monitoredItemCreateResults [ 0 ]:
0000000000: statusCode: 0x80440000 (BadMonitoredItemFilterUnsupported)
0000000000: monitoredItemId: 0
0000000000: revisedSamplingInterval: 0
0000000000: revisedQueueSize: 0
0000000000: filterResult: [empty]
0000000000: Event complete
解决方法
在我看来，您正在尝试使用正在为其创建 MonitoredItem 的节点的 NodeId 而不是标识您正在使用的过滤器结构的 DataTypeEncoding 的 NodeId 来构建包含过滤器结构的 ExtensionObject .