4882query.cs

WDM驱动编程的电子书,值得参考,很经典的

using System;
using System.Runtime.InteropServices;         // Used for _getch() to monitor user inputs
using NationalInstruments.NI4882;     // This namespace must be included to reference the .NET language interface

namespace NI_C_SHARP
{
	/// <summary>
	/*
	*
	*  This sample application is comprised of three basic parts:
	*
	*  1. Initialization
	*  2. Main Body
	*  3. Cleanup
	*
	*  The Initialization portion consists of initializing the bus and the
	*  GPIB interface board so that the GPIB board is Controller-In-Charge
	*  (CIC). Next it finds all the listeners and then clears all the
	*  devices on the bus.
	*
	*  In the Main Body, this application queries a device for its
	*  identification code by issuing the '*IDN?' command. Many
	*  instruments respond to this command with an identification string.
	*  Note, 488.2 compliant devices are required to respond to this
	*  command.
	*
	*  The last step takes the board offline.
	*
	*/
	/// </summary>
	class _4882Query
	{
		private static LangInt li;                          // declare an instance of the .NET language interface functions
		private static GpibConstants c;                     // declare an instance of the .NET language interface constants
		private const int ARRAYSIZE = 100;					// size of ReadBuffer
		private static int Num_Listeners,					// number of listeners on GPIB bus
						   loop,					        // loop counter
						   board;					        // GPIB board number		
		private static short[] Instruments;		            // array of primary addresses
		private static short[] Result; 						// array of listen addresses
		private static string ReadBuffer;                   // contains the string returned from instrument
		private static string[] ErrorMnemonic = {"EDVR", "ECIC", "ENOL", "EADR", "EARG",          // Error codes
												   "ESAC", "EABO", "ENEB", "EDMA", "",
												   "EOIP", "ECAP", "EFSO", "", "EBUS",
												   "ESTB", "ESRQ", "", "", "", "ETAB"};
		
		[DllImport("msvcrt.dll")]
		public static extern char _getch();   //Silently inputs a user keystroke

		[STAThread]
		static void Main(string[] args)
		{
			// try this block of code until an exception is thrown
			try  
			{
				/*
				*  Allocate memory space for the classes and arrays
				*/
				li = new LangInt();          // Contains all GPIB functions
				c = new GpibConstants();     // Contains all GPIB global constants
				Instruments = new short[32]; // An array containing all instrument addresses (1-32)
				Result = new short[31];      // An array that holds the addresses of instruments found on the bus
				board = 0;                   // specifies the GPIB board to use - GPIB0
		
				/*
				*  Your board needs to be the Controller-In-Charge in order to find
				*  all listeners on the GPIB.  To accomplish this, the function
				*  SendIFC is called.  If the error bit ERR is set in ibsta, throw
				*  an error message.
				*/
				li.SendIFC(board);
				if ((li.ibsta & c.ERR)!=0)
					throw new System.Exception("Unable to open board");   // throw an error				
				
				/*
				*  Create an array containing all valid GPIB primary addresses,
				*  except for primary address 0.  Your GPIB interface board is at
				*  address 0 by default.  This array (Instuments) will be given to
				*  the function FindLstn to find all listeners.  
				*/
				for (loop = 0; loop < 30; loop++) 
					Instruments[loop] = (short)(loop + 1);
				
				Instruments[30] = c.NOADDR;

				/*
				*  Print message to tell user that the program is searching for all
				*  active listeners.  Find all of the listeners on the bus.  Store
				*  the listen addresses in the array Result.  Note, the instruments
				*  must be powered on and connected with a GPIB cable in order for
				*  FindLstn to detect them.  If the error bit ERR is set in ibsta, throw
				*  an error message.
				*/
				
				Console.Write("Finding all listeners on the bus..." + System.Environment.NewLine);
				li.FindLstn(board, Instruments, Result, 31);
				if ((li.ibsta & c.ERR)!=0)
					throw new System.Exception("Unable to issue FindLstn call");  // throw an error
			
				/*
				*  ibcntl contains the actual number of addresses stored in the
				*  Result array. Assign the value of ibcntl to the variable
				*  Num_Listeners. Print the number of listeners found.
				*/
				Num_Listeners = li.ibcntl;
				Console.Write("Number of Instruments found = " + Num_Listeners + System.Environment.NewLine);
									
				/*
				*  The Result array contains the addresses of all listening devices
				*  found by FindLstn. Use the constant NOADDR, as defined in
				*  GPIBConstants to terminate the array.
				*/
				Result[Num_Listeners] = c.NOADDR;

				/*
				*  DevClearList will send the GPIB Selected Device Clear (SDC)
				*  command message to all the devices on the bus.  If the error bit
				*  ERR is set in ibsta, throw an error message.
				*/
				li.DevClearList(board,Result);
				if ((li.ibsta & c.ERR)!=0)
					throw new System.Exception("Unable to clear devices");   // throw an error			

				/*
				*  Send the identification query to each listen address in the array
				*  (Result) using SendList.  The constant NLend, defined in GPIBConstants,
				*  instructs the function SendList to append a linefeed character
				*  with EOI asserted to the end of the message.  If the error bit ERR
				*  is set in ibsta, throw an error message.
				*/
				li.SendList(board, Result, "*idn?", 5, c.NLend);
				if ((li.ibsta & c.ERR)!=0)
					throw new System.Exception("Unable to write to devices");												

				/*
				*  Read each device's identification code, one at a time.
				*
				*  Establish a FOR loop to read each one of the device's
				*  identification code. The variable LOOP will serve as a counter
				*  for the FOR loop and as the index to the array Result.
				*/
				Console.Write("Returned string:" + System.Environment.NewLine);
				for (loop = 0; loop < Num_Listeners; loop++)
				{
					/*
					*  Read the name identification response returned from each
					*  device. Store the response in the array ReadBuffer.  The
					*  constant STOPend, defined in GPIBConstants, instructs the
					*  function Receive to terminate the read when END is detected.
					*  If the error bit ERR is set in ibsta, throw an error message
					*/
					li.Receive(board, Result[loop], out ReadBuffer, ARRAYSIZE, c.STOPend);
				
					//Print out the ReadBuffer 
					Console.Write("Address: " + Result[loop].ToString() + ", " + ReadBuffer + System.Environment.NewLine);

				}

			}
			// Execute this block when an exception is thrown
			catch (System.Exception caught)
			{
				//Print out error messages
				Console.WriteLine(System.Environment.NewLine +
					"Error: " + caught.Message + System.Environment.NewLine +  //error Name
					"ibsta = " + li.ibsta + System.Environment.NewLine +       //ibsta
					"iberr = " + li.iberr + System.Environment.NewLine +       //iberr
					ErrorMnemonic[li.iberr] + System.Environment.NewLine);     //error code
			}
			// Always execute this block to ensure that the GPIB board is taken offline
			finally  
			{
				//Allow the user to see the output before exiting.
				Console.Write(System.Environment.NewLine + "Hit Any Key to exit" + System.Environment.NewLine);
				_getch();

				//Take the board offline.
				Console.Write("Taking board offline" + System.Environment.NewLine);
				li.ibonl (board, 0);
				li.Dispose();
			}
        
		}
	}
}