/// /* ReadCoils函数： 读继电器的状态 ， 成功返回ture。 send 数据长度=12 recv 数据长度=10 unsigned short int addr 读继电器的起始地址(继电器编号-1) 。 注意：1~8个继电器，起始地址从0开始 unsigned short int len 读取继电器的个数，最大8. debug_state 如果为1 打印出调式信息 ubool *paraDO 读出的继电器状态 SOCKET s_bnc,fd_set fds,timeval tv 是辅助的网络接口参数 */ /// inline bool ReadCoils(unsigned short int addr, byte & coilstate, SOCKET_INT s_bnc) { cmd_len = 12; byte cmd_code = 1; //命令代码：01，读继电器 byte *cmd_string ; byte *echo_string ; cmd_string = new byte[cmd_len] ; echo_string = new byte[cmd_len] ; cmd_string[ 0] = 0 ; // modbus 协议规定标示 cmd_string[ 1] = 0 ; cmd_string[ 2] = 0 ; cmd_string[ 3] = 0 ; cmd_string[ 4] = 0 ; // length 高位部分 命令的后续字节数量 cmd_string[ 5] = 6 ; // length 低位部分 命令的后续字节数量 cmd_string[ 6] = 0 ; // Unit Identifier :identification of a remote slave connected on a serial line or on other buses. cmd_string[ 7] = cmd_code ; cmd_string[ 8] = (unsigned char) (addr >> 8); cmd_string[ 9] = (unsigned char) addr; cmd_string[10] = 0; //(unsigned char) (len >> 8); cmd_string[11] = 8; //(unsigned char) len ; int iret; fd_set fds; struct timeval tv; tv.tv_sec = SLEEP ; //超时等待时 tv.tv_usec = 0; FD_ZERO(&fds); FD_SET(s_bnc, &fds); /* wait for permission to send(等待是否可写write)*/ iret = select(s_bnc +1, NULL, &fds, NULL, &tv); /*write*/ if (iret=0) { if(debug_state) printf("Timer over!n"); close(s_bnc); return false ; } else if (iret<0) { if(debug_state) printf("select is err! n"); close(s_bnc); return false ; } /*send 写入数据 */ iret = send(s_bnc, (char *)cmd_string, cmd_len , 0); if (iret < cmd_len) { if(debug_state) printf("failed to send chars:%dn",iret); close(s_bnc); return false; } /*wait for response(等待是否可读read)*/ FD_SET(s_bnc, &fds); iret = select(s_bnc +1 , &fds, NULL, NULL, &tv); if (iret=0) { if(debug_state) printf("Timer over!n"); close(s_bnc); return false ; } else if (iret<0) { if(debug_state) printf("select is err! n"); close(s_bnc); return false ; } /*读出数据 */ iret = recv(s_bnc, (char *)echo_string, 12 , 0); if (iret<=0) { if(debug_state) printf("接受数据recv语句出错n"); } if ( echo_string[7] == cmd_code) /*7位置是命令*/ { /*if(debug_state) printf("n读数据成功了n");*/ } else if ( echo_string[7] == (0x80 | cmd_code)) { if(debug_state) printf("设备主动报告:操作出错n"); return false; } else { if(debug_state) printf("出错n"); return false; } //int nDOFlag = echo_string[9] |echo_string[10] << 8); //9位置10位置是继电器的状态 //unsigned char nDOFlag = echo_string[9]; //因为E3018只有8个继电器,故没有10位置 coilstate = echo_string[9]; delete []cmd_string; delete []echo_string; return true; }
全部程序正在完善中。