/// <summary>
        /// 关闭设备
        /// </summary>
        public override bool DevClose()
        {
            bool res = true;
            int  st  = ReaderDllMethod.mwDevClose(handle); //关闭设备

            if (st < 0)
            {
                res = false;
            }
            else
            {
                DevBeep(1, 1, 3);
            }
            return(res);
        }