using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace Mesnac.Equip.Siemens.S7.MPI
{
    /// <summary>
    /// 西门子S7-300PLC串口通讯接口类
    /// </summary>
    public class W95_S7
    {
        /*
            PAdressType = ^AdressType;
            AdressType = packed record
                Adress             : Char; // stationsadresse     default 2
                SegmentId          : Char; // segment id          default 0
                SlotNo             : Char; // slot no             default 1
                RackNo             : Char; // rack no             default 0
            end;

            function load_tool(a:char; b:PChar; c:PAdressType):integer;stdcall;external'W95_S7.dll';
            function db_read(a,b:integer;var c:integer;d:pointer): Integer;stdcall;external'W95_s7.dll';
            function db_write(a,b:integer;var c:integer;d:pointer):integer;stdcall;external'W95_s7.dll';
            function unload_tool():integer;stdcall;external'W95_s7.dll';
         */
        /// <summary>
        /// 定义MPI链接参数
        /// </summary>
        public struct PLCConnParam
        {
            /// <summary>
            /// 定义CPU的MPI地址
            /// </summary>
            public byte Adress;
            //public byte SegmentId;    //保留为0
            /// <summary>
            /// 定义CPU的机架号
            /// </summary>
            public byte RackNo;
            /// <summary>
            /// 定义CPU的槽号
            /// </summary>
            public byte SlotNo;
        }
        /// <summary>
        /// 与PLC建立连接,该函数必须在其他所有函数调用之前被调用
        /// 在一个MPI网络中若有多个CPU时，可指定多个连接列。最后一列的所有参数须置0，以标志参数列结束。
        /// e.g.一个MPI网中有两个CPU,他们的MPI地址分别为2和3，槽号均为2，机架号均为0，则可按如下方式调用:
        /// byte[,] btr={{2,0,2,0},{3,0,2,0},{0,0,0,0}};  int err=load_tool(1, "s7online",btr);
        /// </summary>
        /// <param name="nr">连接数,在DOS,WIN3.1最多可以有4个,在WIN95以上最多可以有16个</param>
        /// <param name="device">与PLC通讯的设备名称,一般为S7ONLINE</param>
        /// <param name="adr_table">参数列表,4个值分别为MPI/DP地址,保留值=0,槽号,机架号</param>
        /// <returns>0正常返回,非0为错误号</returns>
        [DllImport("W95_S7.dll")]
        public extern static int load_tool(byte nr, string device, byte[,] adr_table);
        /// <summary>
        /// 从DB中读取ushort数组(长度是WORD倍数,即双BYTE)
        /// </summary>
        /// <param name="dbno">DB块号</param>
        /// <param name="dwno">DBW起始编号,=0表示DBW0,=1表示DBW2,跨度为WORD</param>
        /// <param name="anzahl">读取的WORD长度(1个WORD==2个BYTE)</param>
        /// <param name="buffer">返回值,ushort型buffer</param>
        /// <returns>0正常返回,非0为错误号</returns>
        [DllImport("W95_S7.dll")]
        public extern static int db_read(int dbno, int dwno, ref int anzahl, ushort[] buffer);
        /// <summary>
        /// 向DB数据块中写入数据
        /// </summary>
        /// <param name="dbno">指定DB块号</param>
        /// <param name="dwno">指定写入的起始字序号，=0表示DBW0,=1表示DBW2</param>
        /// <param name="anzahl">指定写入的对象有多少个字</param>
        /// <param name="buffer">写入值</param>
        /// <returns>0正常返回,非0为错误号</returns>
        [DllImport("W95_S7.dll")]
        public extern static int db_write(int dbno, int dwno, ref int anzahl, ushort[] buffer);
        /// <summary>
        /// 断开与PLC的连接,必须在退出软件之前调用,否则PLC的连接一直被占用,影响下次连接
        /// </summary>
        /// <returns>0正常返回,非0为错误号</returns>
        [DllImport("W95_S7.dll")]
        public extern static int unload_tool();

    }
}