Technologic Systems TS-7100 Series, Manual

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In the output above, columns 6 and 7 are the current RPM value. This shows a simple way to prove out the
communication before moving to another language.
The following example sends the same packet and parses the same response in C:
#include <stdio.h>
#include <pthread.h>
#include <net/if.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <assert.h>
#include <linux/can.h>
#include <linux/can/raw.h>
int main ( void )
{
int s ;
int nbytes ;
struct sockaddr_can addr ;
struct can_frame frame ;
struct ifreq ifr ;
struct iovec iov ;
struct msghdr msg ;
char ctrlmsg [ CMSG_SPACE ( sizeof ( struct timeval )) + CMSG_SPACE ( sizeof ( __u32 ))] ;
char * ifname = "can0" ;
if (( s = socket ( PF_CAN , SOCK_RAW , CAN_RAW )) < 0 ) {
perror ( "Error while opening socket" ) ;
return - 1 ;
}
strcpy ( ifr. ifr_name , ifname ) ;
ioctl ( s , SIOCGIFINDEX , & ifr ) ;
addr. can_family = AF_CAN ;
addr. can_ifindex = ifr. ifr_ifindex ;
if ( bind ( s , ( struct sockaddr * ) & addr , sizeof ( addr )) < 0 ) {
perror ( "socket" ) ;
return - 2 ;
}
/* For the ozen myOByDic 1610 this requests the RPM guage */
frame. can_id = 0x7df ;
frame. can_dlc = 3 ;
frame. data [ 0 ] = 3 ;
frame. data [ 1 ] = 1 ;
frame. data [ 2 ] = 0x0c ;
nbytes = write ( s , & frame , sizeof ( struct can_frame )) ;
if ( nbytes < 0 ) {
perror ( "write" ) ;
return - 3 ;
}
iov. iov_base = & frame ;
msg. msg_name = & addr ;
msg. msg_iov = & iov ;
msg. msg_iovlen = 1 ;
msg. msg_control = & ctrlmsg ;
iov. iov_len = sizeof ( frame ) ;
msg. msg_namelen = sizeof ( struct sockaddr_can ) ;
msg. msg_controllen = sizeof ( ctrlmsg ) ;
msg. msg_flags = 0 ;
do {
nbytes = recvmsg ( s , & msg , 0 ) ;
if ( nbytes < 0 ) {
perror ( "read" ) ;
return - 4 ;
}
if ( nbytes < ( int ) sizeof ( struct can_frame )) {
fprintf ( stderr , "read: incomplete CAN frame \n " ) ;
}
} while ( nbytes == 0 ) ;