【发布时间】：2014-10-09 11:00:53
【问题描述】：
我正在使用 OpcNetApi 与 kepware 进行通信。我尝试从 kepware 读取一些值（超过 40 个值）但是当我的程序执行 opc 服务器的读取方法时，它会等待大约 10 秒来读取我想要的值。那太多了。我不想让它等那么久。我希望它执行读取方法最多 1 秒我不知道是什么问题。为什么 opc 读取值非常慢？有什么办法让它更快。
这是我的 OPC 课程
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace VestelTest
{
class clsOPC
{
private static Opc.Da.Server server = null;
private static Opc.Da.SubscriptionState groupState;
private static Opc.Da.Subscription group;
public clsOPC()
{
}
public static void Connect()
{
//OpcCom.ServerEnumerator se = new OpcCom.ServerEnumerator();
//Opc.Server[] servers = se.GetAvailableServers(Opc.Specification.COM_DA_20);
//Opc.Da.Server server = null;
Opc.URL url = new Opc.URL("opcda://localhost/KEPware.KEPServerEX.V4");
OpcCom.Factory fact = new OpcCom.Factory();
server = new Opc.Da.Server(fact, url);
server.Connect();
groupState = new Opc.Da.SubscriptionState();
groupState.Name = "Salla";
groupState.Active = false;
group = (Opc.Da.Subscription)server.CreateSubscription(groupState);
}
public static void Read(Opc.Da.Item[] items, Opc.Da.ReadCompleteEventHandler method)
{
//Opc.Da.ItemValueResult[] sonuclar = group.Read(group.Items);
if (group != null)
{
//server.Subscriptions.Clear();
groupState = new Opc.Da.SubscriptionState();
groupState.Name = "Salla";
groupState.Active = false;
server.CancelSubscription(group);
group = null;
group = (Opc.Da.Subscription)server.CreateSubscription(groupState);
items = group.AddItems(items);
Opc.IRequest req;
group.Read(group.Items, 123, method, out req);
}
//return sonuclar;
}
public static Opc.Da.ItemValueResult[] Read(Opc.Da.Item[] items)
{
Opc.Da.ItemValueResult[] sonuclar = new Opc.Da.ItemValueResult[items.Length];
if (group != null)
{
//server.Subscriptions.Clear();
groupState = new Opc.Da.SubscriptionState();
groupState.Name = "Salla";
groupState.Active = false;
server.CancelSubscription(group);
group = null;
group = (Opc.Da.Subscription)server.CreateSubscription(groupState);
items = group.AddItems(items);
//sonuclar = group.Read(group.Items);
sonuclar = server.Read(items);
}
return sonuclar;
}
public static void Write(Opc.Da.Item[] writeItems, Opc.Da.ItemValue[] writeValues, Opc.Da.WriteCompleteEventHandler method, Opc.Da.ReadCompleteEventHandler methodRead)
{
if (group != null)
{
//server.Subscriptions.Clear();
groupState = new Opc.Da.SubscriptionState();
groupState.Name = "Salla";
groupState.Active = false;
server.CancelSubscription(group);
group = null;
group = (Opc.Da.Subscription)server.CreateSubscription(groupState);
writeItems = group.AddItems(writeItems);
for (int i = 0; i < writeItems.Length; i++)
{
if (writeValues[i] != null)
writeValues[i].ServerHandle = group.Items[i].ServerHandle;
}
Opc.IRequest req;
group.Write(writeValues, 321, method, out req);
System.Threading.Thread.Sleep(1000);
group.Read(group.Items, 123, methodRead, out req);
}
}
public static void Write(Opc.Da.Item[] writeItems, Opc.Da.ItemValue[] writeValues)
{
if (group != null)
{
//server.Subscriptions.Clear();
groupState = new Opc.Da.SubscriptionState();
groupState.Name = "Salla";
groupState.Active = false;
server.CancelSubscription(group);
group = null;
group = (Opc.Da.Subscription)server.CreateSubscription(groupState);
writeItems = group.AddItems(writeItems);
for (int i = 0; i < writeItems.Length; i++)
{
if (writeValues[i] != null)
writeValues[i].ServerHandle = group.Items[i].ServerHandle;
}
Opc.IRequest req;
group.Write(writeValues);
}
}
public static void Disconnect()
{
server.Disconnect();
}
static void ReadCompleteCallback(object clientHandle, Opc.Da.ItemValueResult[] results)
{
Console.WriteLine("Read completed");
foreach (Opc.Da.ItemValueResult readResult in results)
{
Console.WriteLine("\t{0}\tval:{1}", readResult.ItemName, readResult.Value);
}
Console.WriteLine();
}
static void WriteCompleteCallback(object clientHandle, Opc.IdentifiedResult[] results)
{
Console.WriteLine("Write completed");
foreach (Opc.IdentifiedResult writeResult in results)
{
Console.WriteLine("\t{0} write result: {1}", writeResult.ItemName, writeResult.ResultID);
}
Console.WriteLine();
}
}
}
我是这样用的；
int deviceID = vChannelDevice[i].device.ID;
var vAdres = (from adres in d.tblAddress join groupp in d.tblGroup on adres.GroupID equals groupp.ID join device in d.tblDevice on groupp.DeviceID equals device.ID where device.ID == deviceID select new { adres, groupp, device }).ToList();
if (vAdres.Count > 0)
{
Opc.Da.Item[] valueItems = new Opc.Da.Item[vAdres.Count];
for (int j = 0; j < vAdres.Count; j++)
{
valueItems[j] = new Opc.Da.Item();
valueItems[j].ItemName = vChannelDevice[i].channel.Ad + "." + vChannelDevice[i].device.Ad + "." + vAdres[j].groupp.Ad + "." + vAdres[j].adres.Ad;
}
Opc.Da.ItemValueResult[] valueResults = new Opc.Da.ItemValueResult[vAdres.Count];
if (backgroundWorker1.CancellationPending)
{
e.Cancel = true;
return;
}
valueResults = clsOPC.Read(valueItems);
for (int j = 0; j < vAdres.Count; j++)
{
if (valueResults[j] != null)
{
if (valueResults[j].Value != null)
{
Kaydet(vAdres[j].adres.ID, Convert.ToDouble(valueResults[j].Value), donguTarih);
}
}
}
}
valueResults = clsOPC.Read(valueItems); 行等待太多
【问题讨论】：
-
在
Read()方法中的哪个位置发生了暂停？是在线sonuclar = server.Read(items);吗？ -
那么很明显是服务器的响应滞后了，而不是您对值的请求。
-
为什么会滞后？我怎样才能让它反应更快？
-
您必须询问 Kepware。这里的人不太可能知道。
-
我在 Kepware 中进行 OPC 测试时注意到的是，如果项目尚未订阅，则需要一些时间。不确定这是否是 OPC 的工作方式，但后续读取通常非常快，因为服务器将激活标签/项目。