这是我与机器人和s7 plc通信的巨大代码的一部分，并行工作。问题是，在此之前，虽然问题是plc通信的一部分，但现在我已将所有代码都减少到客户端 - 服务器应用程序，这似乎也失败了。 代码基本上以下一种方式工作;客户端每50ms向服务器发送一条“hello”消息。当发送20条消息时，将启动7秒的计时器。当触发计时器时，启动第二个线程，并且这个更改变量f = 1并完成。同时主程序将打印你好，但是当这个变量f变为1时，它应该只打印“aaaaa”，但它永远不会发生。
使用PLC，问题是分段故障。我的想法是TCP通信失败（为什么？）并且PLC阻止访问。我在移动机器人手臂之前尝试了相同的程序，并使用wireshark进行分析，您可以看到TCP是如何一直发送的，但机器人再次停止。 最后，通过这个客户端应用程序，可以看到它们如何不能按预期工作。
我希望你们中的任何人都可以帮助我。
非常感谢;）
客户端
#include <stdlib.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h> // Primitive System Data Types
#include <errno.h> // Errors */
#include <sys/wait.h> // Wait for Process Termination
#include "plc_interface.h"
#include <netinet/in.h>
#include <time.h>
#include <signal.h>
#include <pthread.h>
#include <semaphore.h>
#include <time.h>
#include <unistd.h>
#include <sys/time.h>
#include <fcntl.h>
#include <sys/socket.h>
timer_t firstTimerID;
timer_t secondTimerID;
struct itimerspec it;
int t_block3=5;
pthread_t thread_robot;
pthread_attr_t thread_attr;
int res, z;
int f=0;
//THREAD FUNCTION ONCE THE REQUIRED BLOCK IS DETECTED
void *detection_robot(){
printf("First\n");
//f==1 to send the message aaaaaa
f=1;
pthread_exit(NULL);
}
int setTimer(timer_t * timerID, int time) {
struct itimerspec its;
//Interval for starting again
its.it_interval.tv_sec = 0;
its.it_interval.tv_nsec = 0;
//Timer time
its.it_value.tv_sec = time;
its.it_value.tv_nsec = 0;
//Arm/disarmer a per process time
timer_settime (*timerID, 0, &its, NULL);
return 0;
}
//TIMER INTERRUPTION
static void timerHandler (int sig, siginfo_t * si, void *uc_) {
timer_t *tidp;
int iret;
tidp = si->si_value.sival_ptr;
//Initializes the attributes for the thread
res= pthread_attr_init(&thread_attr);
res=pthread_attr_setdetachstate(&thread_attr,PTHREAD_CREATE_DETACHED);
if (*tidp == firstTimerID) {
printf ("First timer\n");
//New thread to detect the second detection sensor
iret = pthread_create( &thread_robot, &thread_attr, detection_robot, NULL);
if(iret)
{
fprintf(stderr,"Error - pthread_create() return code: %d\n",iret);
exit(EXIT_FAILURE);
}
} else if (*tidp == secondTimerID) {
printf ("Second timer\n");
}
z--;
}
//ARM THE TIMERS
static int makeTimer (timer_t * timerID) {
struct sigevent te;
struct sigaction sa;
int sigNo = SIGRTMIN;
// Set up signal handler.
sa.sa_flags = SA_SIGINFO;
sa.sa_sigaction = timerHandler; //Action when singal is triggered
sigemptyset (&sa.sa_mask);
if (sigaction (sigNo, &sa, NULL) == -1) {
perror ("sigaction");
}
// Set and enable alarm
te.sigev_notify = SIGEV_SIGNAL; //Gnerate alarm upon expiration
te.sigev_signo = sigNo; //SIGALRM
te.sigev_value.sival_ptr = timerID; //Timer ID
//Create a per_process timer using the timer ID
timer_create (CLOCK_REALTIME, &te, timerID);
return 0;
}
int main(int argc , char *argv[])
{
int sock;
struct sockaddr_in server;
char message[6]={'h','e','l','l','o','\0'};
char message2[6]={'a','a','a','a','a','\0'};
char server_reply[2000];
//Initialize the timers
makeTimer(&firstTimerID);
makeTimer(&secondTimerID);
//Create socket
sock = socket(AF_INET , SOCK_STREAM , 0);
if (sock == -1)
{
printf("Could not create socket");
}
puts("Socket created");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 8888 );
//Connect to remote server
if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
{
perror("connect failed. Error");
return 1;
}
puts("Connected\n");
//keep communicating with server
int i=0;
while(1){
//Send hello every 50ms
if( send(sock , message , 6 , 0) < 0)
{
puts("Send failed");
return 1;
}
i++;
if (i==20){
setTimer (&firstTimerID, t_block3);
i=0;
}
//f-> 1, send aaaaaa when timer is triggered, but here is when it get stacked
if (f==1) {
f=0;
if( send(sock , message2 , 6 , 0) < 0)
{
puts("Send failed");
return 1;
}}
usleep(500000); //500ms
}
}
SERVER
#include<stdio.h>
#include<string.h> //strlen
#include<sys/socket.h>
#include<arpa/inet.h> //inet_addr
#include<unistd.h> //write
int main(int argc , char *argv[])
{
int socket_desc , client_sock , c , read_size;
struct sockaddr_in server , client;
char client_message[2000];
//Create socket
socket_desc = socket(AF_INET , SOCK_STREAM , 0);
if (socket_desc == -1)
{
printf("Could not create socket");
}
puts("Socket created");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 8888 );
//Bind
if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
{
//print the error message
perror("bind failed. Error");
return 1;
}
puts("bind done");
//Listen
listen(socket_desc , 3);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
//accept connection from an incoming client
client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c);
if (client_sock < 0)
{
perror("accept failed");
return 1;
}
puts("Connection accepted");
while(1){
//Receive a message from client
recv(client_sock , client_message , 2000 , 0);
printf("%s\n", client_message);
}
}
答案 0 :(得分：0)
问题在于作业：
f = 1;
对其他线程不可见，因此main()线程永远不会看到更改。要更正，您需要使用同步机制，例如pthread_mutex_t，必须在读取或写入f时获取，或atomic_int，如果您的编译器具有C11支持。
答案 1 :(得分：0)
已解决，评论中的解释：）
代码已解决，只需将互斥锁添加为hmjd建议。谢谢;）
我没有清楚这是互斥问题，因为在我正在使用的其他代码中，没有可能导致代码/通信中断的共享变量。我将在这里介绍我的plc代码，以显示我正在使用的内容。我删除了与机器人的额外tcp通信，我只是在这里呈现连续读取的PLC存储器，它一直非常稳定，但在触发简单定时器时会中断（并不总是）。如果更换机器人的PLC，这只是正常的tcp通信发送移动命令，仍然会发生相同的情况。
#include <stdlib.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <string.h>
#include "nodavesimple.h"
#include "nodave.h"
#include "openSocket.h"
#include "plc_interface.h"
#include <sys/types.h> // Primitive System Data Types
#include <errno.h> // Errors */
#include <sys/wait.h> // Wait for Process Termination
#include "plc_interface.h"
#include <netinet/in.h>
#include <time.h>
#include <signal.h>
#include <pthread.h>
#include <semaphore.h>
#ifdef LINUX
#include <unistd.h>
#include <sys/time.h>
#include <fcntl.h>
#define UNIX_STYLE
#endif
#ifdef BCCWIN
#include <time.h>
void usage(void);
#define WIN_STYLE
#endif
#ifdef PLAY_WITH_KEEPALIVE
#include <sys/socket.h>
#endif
timer_t firstTimerID;
struct itimerspec it;
int t_block3=3;
pthread_t thread_robot;
pthread_attr_t thread_attr;
int robot_detection=0;
//THREAD FUNCTION ONCE THE REQUIRED BLOCK IS DETECTED
void *detection_robot(){
printf("First\n");
pthread_exit(0);
}
//TIMER INTERRUPTION
static void timerHandler (int sig, siginfo_t * si, void *uc_) {
timer_t *tidp;
int iret;
tidp = si->si_value.sival_ptr;
//Initializes the attributes for the thread
pthread_attr_init(&thread_attr);
pthread_attr_setdetachstate(&thread_attr,PTHREAD_CREATE_DETACHED);
if (*tidp == firstTimerID) {
printf ("First timer\n");
//New thread to detect the second detection sensor
iret = pthread_create( &thread_robot, &thread_attr, detection_robot, NULL);
if(iret)
{
fprintf(stderr,"Error - pthread_create() return code: %d\n",iret);
exit(EXIT_FAILURE);
}
}
}
//ARM THE TIMERS
static int makeTimer (timer_t * timerID) {
struct sigevent te;
struct sigaction sa;
int sigNo = SIGRTMIN;
// Set up signal handler.
sa.sa_flags = SA_SIGINFO;
sa.sa_sigaction = timerHandler; //Action when singal is triggered
sigemptyset (&sa.sa_mask);
if (sigaction (sigNo, &sa, NULL) == -1) {
perror ("sigaction");
}
// Set and enable alarm
te.sigev_notify = SIGEV_SIGNAL; //Gnerate alarm upon expiration
te.sigev_signo = sigNo; //SIGALRM
te.sigev_value.sival_ptr = timerID; //Timer ID
//Create a per_process timer using the timer ID
timer_create (CLOCK_REALTIME, &te, timerID);
return 0;
}
int main(int argc, char **argv) {
int adrPos, useProtocol, useSlot;
int res,barcode_number, r, t;
int c=0, a=0;
//Locate the robot in the initial position
//robot_init();
//Initialize the timer
makeTimer(&firstTimerID);
#ifdef PLAY_WITH_KEEPALIVE
int opt;
#endif
daveSetDebug(daveDebugPrintErrors);
adrPos=1;
useProtocol=daveProtoISOTCP;
useSlot=2;
daveInterface * di;
daveConnection * dc;
_daveOSserialType fds;
PDU p;
daveResultSet rs;
//If the input doesn't have enough parameters, printf the usage
if (argc<2) {
usage();
exit(-1);
}
//If there is a problem in the communication it takes 20 seconds to stablish communication again
fds.rfd=openSocket(102, argv[adrPos]);
#ifdef PLAY_WITH_KEEPALIVE
errno=0;
opt=1;
res=setsockopt(fds.rfd, SOL_SOCKET, SO_KEEPALIVE, &opt, 4);
LOG3("setsockopt %s %d\n", strerror(errno),res);
#endif
fds.wfd=fds.rfd;
if (fds.rfd>0) {
di =daveNewInterface(fds,"IF1",0, useProtocol, daveSpeed187k);
daveSetTimeout(di,5000000);
dc =daveNewConnection(di,2,0,useSlot); // insert your rack and slot here
if (0==daveConnectPLC(dc)) {
printf("Connected.\n");
//START THE BELT
a=0;//a=1 to start the belt
printf("Start the belt \n");
res=daveWriteBits(dc, daveDB, 111, 4, 1, &a);
res=daveWriteBits(dc, daveDB, 111, 3, 1, &a);
printf("function result:%d=%s\n", res, daveStrerror(res));
//Remove the memory flag of the detection sensor again
res=daveWriteBits(dc, daveFlags, 0, 504, 1, &c);
res=daveWriteBits(dc, daveFlags, 0, 520, 1, &c);
usleep(2000000);
printf("Trying to read the sensor until block is detected\n");
//SENSOR DETECTION
while(1){
//Read request --> Stable until the timer is triggered
davePrepareReadRequest(dc,&p);
daveAddVarToReadRequest(&p, daveFlags, 0, 63, 1);
daveAddVarToReadRequest(&p, daveFlags, 0, 65, 1);
daveAddVarToReadRequest(&p, daveDB, 4, 103, 1);
res=daveExecReadRequest(dc, &p, &rs);
if (res==1){ printf("Error during the request\n");}
//First result --> detection sensor after the barcode
res=daveUseResult(dc, &rs, 0);
if (res==1){ printf("Error reading the first result\n");}
t=daveGetU8(dc); //T = 1 if detection in the barcode place
//Second result --> detection sensor before the robot position
res=daveUseResult(dc, &rs, 1);
if (res==1){ printf("Error reading the detection sensor before the robot\n");}
r=daveGetU8(dc); //R = 1 if detection in the robot place
//Third result --> read the number stored
daveUseResult(dc, &rs, 2);
barcode_number=daveGetU8(dc);
//Free the memory
daveFreeResults(&rs);
if (r==1){
//Remove the memory flag referred to the second sensor
res=daveWriteBits(dc, daveFlags, 0, 520, 1, &c);
if (res==1){ printf("Error removing the flag of the second detector\n");}
}
//Wen detection..
if (t==1){
t=0;
//Remove the memory flag of the detection
res=daveWriteBits(dc, daveFlags, 0, 504, 1, &c);
if (res==1){ printf("Error removing the flag of the sensor closed to the robot\n");}
//If number three is detected the belt will stop in 3 seconds respectively
switch(barcode_number){
case 3: printf("Block number three, timer will be triggered in 3 seconds\n");
//Start the timer
setTimer (&firstTimerID, t_block3);
break;
case 2: printf("Block number two, belt won't stop\n");
break;
case 4: printf("Block number four, belt won't stop\n");
break;
default:printf("Wrong lecture\n");
}}
usleep(50000); //Rest until next sampling
}
//Close socket
closeSocket(fds.rfd);
printf("Finished.\n");
return 0;
} else {//daveconnected
printf("Couldn't connect to PLC.\n \n");
closeSocket(fds.rfd);
return -2;}
}//fds.rds > 0
else {
printf("Couldn't open TCP port. \nPlease make sure a CP is connected and the IP address is ok. \n");
return -1;
}
}