尝试通过GPIB写东西显示接口不存在

嗨，我正在尝试通过GPIB与使用Measurament Studio和Agilent 82357B的仪器进行通信。
以下是我所做的：已安装的Measurament工作室已安装的NI 488驱动程序已安装的NI Visa驱动程序已安装的Agilent Libraries 488支持在Agilent Connection Expert上启用NI自动化浏览器中的Tulipvisa.dll然后我尝试使用NI示例进行visual studio（简单读取）
用C＃写入，但当我尝试通过GPIB写一些东西时，它说：不存在的GPIB接口。
我可以在自动化浏览器和安捷伦连接专家中看到GPIB，如果我使用NI Labwindows CVI，我可以通过GPIB进行通信而没有任何问题。
任何提示？
谢谢



     以下为原文

  Hi, i am trying to communicate via GPIB to an instrument with Measurament Studio and the Agilent 82357B .

Here is what i have done:

Installed Measurament studio
Installed NI 488 drivers
Installed NI Visa drivers
Installed Agilent Libraries
Enabled 488 Support on Agilent Connection Expert
Enabled Tulipvisa.dll in NI Automation Explorer

Then I tried to use a NI example for visual studio (Simple Read Write in C#) but when i try to write something via GPIB it says: Nonexistent GPIB interface.

I can see the GPIB in the Automation explorer and in the agilent connection expert, If i use NI Labwindows CVI i can communicate via GPIB without any problem.

Any hint?  

Thank You