一、中断、多线程、多任务
中断是一种使CPU中止正在执行的程序而转去处理特殊事件的操作。在运行一个程序的过程中，断续地以“插入”方式执行一些完成特定处理功能的程序段。
硬件多线程是指多核的CPU，例如英特尔的入门级CPU i3 10100为4核八线程、AMD的Ryzen 3 3300X为4核八线程。
软件多线程则是通过快速的在不同线程之间进行切换，由于时间间隔很短从而给人造成一种多个线程同时运行的假象。一条线程指的是进程中一个单一顺序的控制流，一个进程中可以并发多个线程，每条线程并行执行不同的任务。
多任务，任务是指独立的应用程序，“多任务”类似于手机或者电脑的应用程序的“两开”、“多开”。abb有一个选项包623-1 multitasking 可以实现最多同时运行14个RAPID程序，用于监控外部设备或先进计算。
二、中断触发socket发送实时位置给上位机，0.1s周期，精确到小数点后2位
abb提供了永久变量改变时中断、模拟量信号到达指定范围时中断、数字量及组输入组输出信号为1时或改变时中断、定时触发中断等。
那么，咱们做个例子，plc或上位机点击按钮实现实时位置上传功能。首先想到的实现方法是为abb添加623-1 multitasking选项包，不过现在咱们了解了中断，用两个中断也可实现这个功能。
先用永久变量改变时中断触发一个中断程序，再在这个中断程序中添加此永久变量为1时，启动定时中断，触发最小间隔为0.1s的、发送当前实时位置的程序。
LOCAL VAR num server_port:=4002;LOCAL VAR socketdev server_socket;LOCAL VAR socketdev client_socket;PERS num Sync_var_robot;LOCAL VAR intnum intr_var;LOCAL VAR intnum intr_send_robstatus;LOCAL CONST num send_cycletime:=0.1;VAR string receiveStr;VAR num receiveDataNumb;VAR bool OK;VAR robtarget CurrentPos;VAR num CurrentX;VAR num CurrentY;VAR num CurrentZ;VAR num CurrentA;VAR num CurrentB;VAR num CurrentC;VAR string sendStr;PROC main()Init_socket server_socket,server_port;Wait_for_client server_socket,client_socket;init_var_interrupt;WHILE TRUE DOIF (SocketGetStatus(client_socket)=SOCKET_CONNECTED) THENSocketReceive client_socket, \str:=receiveStr\NoRecBytes:=receiveDataNumb;ELSEExitCycle;ENDIFOK:=StrToVal(receiveStr,Sync_var_robot);ENDWHILEENDPROCPROC Init_socket(VAR socketdev server_socket,num port)IF (SocketGetStatus(client_socket)<>SOCKET_CLOSED) SocketClose client_socket;IF (SocketGetStatus(server_socket)<>SOCKET_CLOSED) SocketClose server_socket;IF (SocketGetStatus(server_socket)=SOCKET_CLOSED) SocketCreate server_socket;! GetSysInfo(\LanIp) return "VC" in vitual controler!IF (SocketGetStatus(server_socket) = SOCKET_CREATED) SocketBind server_socket, GetSysInfo(\LanIp), port;IF (SocketGetStatus(server_socket)=SOCKET_CREATED) SocketBind server_socket,"127.0.0.1",port;IF (SocketGetStatus(server_socket)=SOCKET_BOUND) SocketListen server_socket;ERROR! raise errors to calling codeRAISE ;ENDPROCPROC Wait_for_client(VAR socketdev server_socket,VAR socketdev client_socket,\num wait_time)VAR string client_ip;VAR num time_val:=WAIT_MAX;! default to wait-foreverIF Present(wait_time) time_val:=wait_time;! close client_socket for this portIF (SocketGetStatus(client_socket)<>SOCKET_CLOSED) SocketClose client_socket;WaitUntil(SocketGetStatus(client_socket)=SOCKET_CLOSED);! waiting for the connectionTPWrite "waiting for connection.";SocketAccept server_socket,client_socket,\ClientAddress:=client_ip,\Time:=time_val;TPWrite "Client at "+client_ip+" connected.";ERRORRAISE ;ENDPROCLOCAL PROC init_var_interrupt()IDelete intr_var;CONNECT intr_var WITH var_handler;IPers Sync_var_robot,intr_var;ERRORRAISE;ENDPROCLOCAL TRAP var_handlerIDelete intr_send_robstatus;IF (Sync_var_robot=1) THEN! Sync_var_robot = 1 means send robstatusinit_send_robstatus_interrupt;ENDIFENDTRAPLOCAL PROC init_send_robstatus_interrupt()IDelete intr_send_robstatus;CONNECT intr_send_robstatus WITH send_robstatus;ITimer send_cycletime,intr_send_robstatus;ERRORRAISE;ENDPROCLOCAL TRAP send_robstatusCurrentPos :=CRobT();CurrentX:=CurrentPos.trans.x;CurrentY:=CurrentPos.trans.y;CurrentZ:=CurrentPos.trans.z;CurrentC:=EulerZYX(\x,CurrentPos.rot);CurrentB:=EulerZYX(\y,CurrentPos.rot);CurrentA:=EulerZYX(\z,CurrentPos.rot);sendStr:=NumToStr(CurrentX,2)+";"+NumToStr(CurrentY,2)+";"+NumToStr(CurrentZ,2)+";"+NumToStr(CurrentA,2)+";"+NumToStr(CurrentB,2)+";"+NumToStr(CurrentC,2);SocketSend client_socket\str:=sendStr;ENDTRAP
