findinstruments.cs

gpib编程之查找设备,可以遍历出所有存在的设备,采用C#编写

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>
 /* Filename - Findinstruments.c
 *
 *  This sample application initializes the bus and the GPIB interface
 *  board so that the GPIB board is Controller-In-Charge (CIC). It
 *  then proceeds to find all the instruments on the GPIB bus and
 *  print the PAD (Primary Address) and SAD (Secondary Address) of
 *  each instrument.
 *
 */
 /// </summary>
	class FindInstruments
	{
		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 static int Num_Listeners;		        // Number of instruments on GPIB
		private static int PAD;                         // Primary address
		private static int SAD;                         // Secondary address
		private static int loop;                        // Loop counter
		private const int board = 0;                    // GPIB board number
		private static short[] Instruments;		        // Array of primary addresses
		private static short[]	Result;                 // Array of listen addresses
		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
			
			
			
				/*
				*  Your board needs to be the Controller-In-Charge in order to find
				*  all instrument on the GPIB.  To accomplish this, the function
				*  SendIFC is called.  If the error bit ERR is set in ibsta, call
				*  GPIBCleanup with 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 (Instruments) will be given to
				*  the function FindLstn to find all instruments. 
				*/
				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
				*/
				Result[Num_Listeners] = c.NOADDR;

				/*
				*  Print out each instrument's PAD and SAD, one at a time.
				*
				*  Establish a FOR loop to print out the information. The variable
				*  LOOP will serve as a counter for the FOR loop and as the index
				*  to the array Result.
				*/
				for (loop = 0; loop < Num_Listeners; loop++)
				{
					/*
					 *  The low byte of the instrument address is the primary
					 *  address. Assign the variable PAD the primary address of the
					 *  instrument. The macro GetPAD, defined in GPIBConstants, returns
					 *  the low byte of the instrument address.
					 */
					PAD = c.GetPAD((byte)Result[loop]);

					/*
					 *  The high byte of the instrument address is the secondary
					 *  address. Assign the variable SAD the primary address of the
					 *  instrument. The macro GetSAD, defined in NI488.H, returns
					 *  the high byte of the instrument address.
					 */
					SAD = c.GetSAD((byte)Result[loop]);

					if (SAD == c.NO_SAD)
						Console.WriteLine("The instrument at Result[{0}]: PAD = {1} SAD = NONE", loop, PAD);
					else
						Console.WriteLine("The instrument at Result[{0}]: PAD = {1} SAD = {2}", loop, PAD, SAD);
					Console.WriteLine(System.Environment.NewLine);
				}
			}
			// Execute this block when an exception is thrown
			catch (System.Exception caught)
			{
				//Print out error messages
				Console.Write(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();
			}

		}
	}
}