opc

package module
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 Go to latest Published: Jan 20, 2025 License: MIT Imports: 10 Imported by: 0

README

OPC DA in Go

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Read and write process and automation data in Go from an OPC server for monitoring and data analysis purposes (OPC DA protocol).

go get github.com/konimarti/opc

Usage

client, _ := opc.NewConnection(
	"Graybox.Simulator", 		// ProgId
	[]string{"localhost"}, 		// Nodes
	[]string{"numeric.sin.float"}, 	// Tags
)
defer client.Close()
client.ReadItem("numeric.sin.float")

browser, _ := opc.CreateBrowser(
	"Graybox.Simulator", 		// ProgId
	[]string{"localhost"}, 		// Nodes	
)
opc.PrettyPrint(browser)

Installation

  • go get github.com/konimarti/opc
Troubleshooting
  • OPC DA Automation Wrapper 2.02 should be installed on your system (OPCDAAuto.dll or gbda_aut.dll); the automation wrapper is usually shipped as part of the OPC Core Components of your OPC Server.
  • You can get the Graybox DA Automation Wrapper here. Follow the installation instruction for this wrapper.
  • Depending on whether your OPC server and automation wrapper are 32-bit or 64-bit, set the Go architecture correspondingly:
    • For 64-bit OPC servers and wrappers: DLL should be in C:\Windows\System32, use $ENV:GOARCH="amd64"
    • For 32-bit OPC servers and wrappers: DLL should be in C:\Windows\SysWOW64, use $ENV:GOARCH="386"
  • Make sure to have correct DCOM settings on your local and remote computers: Dcomcnfg.exe
Reporting Issues
  • If you find a bug in the code, please create an issue and suggest a solution how to fix it.
  • Issues that are related to connection problems are mostly because of a faulty installation of your OPC automation wrapper or some peculiarties of your specific setup and OPC installation. Since we cannot debug your specific situation, these issues will be directly closed.
Debugging
  • Add opc.Debug() before the opc.NewConnection call to print more debug-related information.
Testing
  • Start Graybox Simulator v1.8. This is a free OPC simulation server and require for testing this package. It can be downloaded here.
  • If you use the Graybox Simulator, set $GOARCH environment variable to "386", i.e. enter $ENV:GOARCH=386 in Powershell.
  • Test code with go test -v

Example

package main

import (
	"fmt"
	"github.com/konimarti/opc"
)

func main() {
	client, _ := opc.NewConnection(
		"Graybox.Simulator", // ProgId
		[]string{"localhost"}, //  OPC servers nodes
		[]string{"numeric.sin.int64", "numeric.saw.float"}, // slice of OPC tags
	)
	defer client.Close()

	// read single tag: value, quality, timestamp
	fmt.Println(client.ReadItem("numeric.sin.int64"))

	// read all added tags
	fmt.Println(client.Read())
}

with the following output:

{91 192 2019-06-21 15:23:08 +0000 UTC}
map[numeric.sin.int64:{91 192 2019-06-21 15:23:08 +0000 UTC} numeric.saw.float:{-36.42 192 2019-06-21 15:23:08 +0000 UTC
}]

Applications

opc-cli

  • opc-cli is a command-line interface to work with OPC servers: list available OPC servers, browse OPC tags on server, and read/write OPC tags.

  • Install it with go install github.com/konimarti/opc/cmds/opc-cli

    • List OPC servers on a specific node:

      $ opc-cli.exe list localhost
Found 3 server(s) on 'localhost':
Graybox.Simulator.1
INAT TcpIpH1 OPC Server
Prosys.OPC.Simulation

    • Browse OPC tags (in sub-branch):

      $ opc-cli.exe browse localhost Graybox.Simulator.1 textual
textual
   - textual.color
   - textual.number
   - textual.random
   - textual.weekday

    • Write to OPC tag:

      $ opc-cli.exe write localhost Graybox.Simulator.1 options.sinfreq 0.01

    • Read OPC tags:

      $ opc-cli.exe read localhost Graybox.Simulator.1 options.sinfreq numeric.sin.float
map[options.sinfreq:{0.05 192 2019-06-21 15:26:02 +0000 UTC} numeric.sin.float:{22.916641 192 2019-06-21 15:26:02 +0000 UTC}]
OPCAPI

  • Application to expose OPC tags with a JSON REST API.

    • Install the app: go install github.com/konimarti/opc/cmds/opcapi

    • Create config file:

      [config]
allow_write = false
allow_add = true
allow_remove = true

[opc]
server = "Graybox.Simulator"
nodes = [ "localhost" ]
tags = [ "numeric.sin.float", "numeric.saw.float" ]

    • Run app:

      $ opcapi.exe -conf api.conf -addr ":4444"

    • Access API:

      • Get tags: 
        $ curl.exe -X GET localhost:4444/tags
{"numeric.saw.float":-21.41,"numeric.sin.float":62.303356}
      • Add tag: 
        $ curl.exe -X POST -d '["numeric.triangle.float"]' localhost:4444/tag
{"result": "created"}
      • Remove tag: 
        $ curl.exe -X DELETE localhost:4444/tag/numeric.triangle.float
{"result": "removed"}
OPCFLUX

  • Application to write OPC data directly to InfluxDB.

    • Install the app: go install github.com/konimarti/opc/cmds/opcflux

    • Create InfluxDB database "test"

    • Create config file: Put OPC tags in []. This is required for the expression evaluation. Any calculation can be performed that can evaluated.

      ---
server: "Graybox.Simulator"
nodes: ["localhost", "127.0.0.1"]
monitoring: ""
influx:
 addr: "http://localhost:8086"
 database: test
 precision: s
measurements: 
 numeric:
   - tags: {type: sin}
     fields: {float: "[numeric.sin.float]", int: "[numeric.sin.int32]"}
   - tags: {type: saw}
     fields: {float: "[numeric.saw.float]", int: "[numeric.saw.int32]"}
   - tags: {type: calculation}
     fields: {float: "[numeric.triangle.float] / [numeric.triangle.int32]"}
 textual:
   - tags: {type: color}
     fields: {text: "[textual.color]", brown: "[textual.color] == 'Brown'"}        
   - tags: {type: weekday}
     fields: {text: "[textual.weekday]"}

    • Run app: opcflux.exe -conf influx.yml -rate 1s

Credits

This software package has been developed for and is in production at Kalkfabrik Netstal.

Documentation

Index

Constants

View Source 
const (
	//OPCDataSource defines constants for Sources when reading data from OPC:
	//Default implementation is OPCCache.
	//From the cache
	OPCCache int32 = 1
	//From the device
	OPCDevice int32 = 2

	//OPCQuality defines the quality of the OPC items:
	//Bad
	OPCQualityBad int16 = 0
	//Good
	OPCQualityGood          int16 = 192
	OPCQualityGoodButForced int16 = 216
	//Maks
	OPCQualityMask int16 = 192
	//Uncertain
	OPCQualityUncertain int16 = 64

	//OPCServerState defines the state of the server:
	//Disconnected
	OPCDisconnected int32 = 6
	//Failed
	OPCFailed int32 = 2
	//Noconfig
	OPCNoconfig int32 = 3
	//Running
	OPCRunning int32 = 1
	//Suspended
	OPCSuspended int32 = 4
	//Test
	OPCTest int32 = 5
)

Variables

This section is empty.

Functions

func CollectTags 

func CollectTags(tree *Tree) []string

CollectTags traverses tree and collects all tags in string slice

func Debug 

func Debug()

Debug will set the logger to print to stderr

func FindOPCWrappers added in v0.1.5 

func FindOPCWrappers() ([]string, error)

func NewConnection 

func NewConnection(server string, nodes []string, tags []string) (Connection, []ErrResult, error)

NewConnection establishes a connection to the OpcServer object.

func OleInit 

func OleInit()

OleInit initializes OLE.

func OleRelease 

func OleRelease()

OleRelease releases OLE resources in opcAutomation.

func PrettyPrint 

func PrettyPrint(tree *Tree)

PrettyPrint prints tree in a nice format

func SetLogWriter 

func SetLogWriter(w io.Writer)

SetLogWriter sets a user-defined writer for logger

func StartMonitoring 

func StartMonitoring(port string)

StartMonitoring exposes /metrics to Prometheus

Types

type AutomationItems 

type AutomationItems struct {
	// contains filtered or unexported fields
}

AutomationItems store the OPCItems.

func NewAutomationItems 

func NewAutomationItems(opcitems *ole.IDispatch) *AutomationItems

NewAutomationItems returns a new AutomationItems instance.

func (*AutomationItems) Add 

func (ai *AutomationItems) Add(tags ...string) ([]string, []ErrResult, error)

Add accepts a variadic parameters of tags.

func (*AutomationItems) Close 

func (ai *AutomationItems) Close()

Close closes the OLE objects in AutomationItems.

func (*AutomationItems) Remove 

func (ai *AutomationItems) Remove(tag string)

Remove removes the tag.

type AutomationObject 

type AutomationObject struct {
	// contains filtered or unexported fields
}

AutomationObject loads the OPC Automation Wrapper and handles the connection to the OPC Server.

func NewAutomationObject 

func NewAutomationObject() *AutomationObject

NewAutomationObject connects to the COM object based on available wrappers.

func (*AutomationObject) Close 

func (ao *AutomationObject) Close()

Close releases the OLE objects in the AutomationObject.

func (*AutomationObject) Connect 

func (ao *AutomationObject) Connect(server string, node string) (*AutomationItems, error)

Connect establishes a connection to the OPC Server on node.

func (*AutomationObject) CreateBrowser 

func (ao *AutomationObject) CreateBrowser(path string) (*Tree, error)

CreateBrowser initializes the OPCBrowser and returns the root or specific branch based on the nextName parameter.

func (*AutomationObject) GetOPCServers 

func (ao *AutomationObject) GetOPCServers(node string) []string

GetOPCServers returns a list of ProgIDs on the specified node

func (*AutomationObject) IsConnected 

func (ao *AutomationObject) IsConnected() bool

IsConnected checks if the server is properly connected.

func (*AutomationObject) TryConnect 

func (ao *AutomationObject) TryConnect(server string, nodes []string) (*AutomationItems, error)

TryConnect tries to connect to any of the nodes.

type Collector 

type Collector interface {
	Get(string) (interface{}, bool)
	Sync(Connection, time.Duration) io.Closer
}

Collector interface

func NewDataModel 

func NewDataModel() Collector

NewDataModel returns an OPC Data struct.

type Connection 

type Connection interface {
	Add(...string) ([]string, []ErrResult, error)
	Remove(string)
	Read() (map[string]Item, error)
	ReadItem(string) Item
	Tags() []string
	Write(string, interface{}) error
	Close()
	IsConnected() bool
	CreateBrowser(path string) (*Tree, error)
}

Connection represents the interface for the connection to the OPC server.

type ErrResult added in v0.2.0 

type ErrResult struct {
	Message string `json:"message"`
	Tag     string `json:"tag"`
}

type Item 

type Item struct {
	Tag       string
	Value     interface{}
	Quality   int16
	Timestamp time.Time
	Err       interface{}
}

Item stores the result of an OPC item from the OPC server.

func (*Item) Good 

func (i *Item) Good() bool

Good checks the quality of the Item

type Leaf 

type Leaf struct {
	Name string
	Tag  string
}

Leaf contains the OPC tag and forms part of the Tree struct for the OPC browser

type Tree 

type Tree struct {
	Name     string
	Parent   *Tree
	Branches []*Tree
	Leaves   []Leaf
}

Tree creates an OPC browser representation

func CreateBrowser 

func CreateBrowser(server string, nodes []string, browser string) (*Tree, error)

CreateBrowser creates an opc browser representation

func ExtractBranchByName 

func ExtractBranchByName(tree *Tree, name string) *Tree

ExtractBranchByName return substree with name

Source Files

View all Source files

Directories

Path Synopsis
cmds
opc-cli
opcapi
opcflux

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