how to get the data from control.c

ArcEye wrote:

Hi

joint_data is of a typedef struct hal_joint_t, which is local to the emcmotController.

It is purely local to that process, if you look at the objects produced by compilation, there is not even a control.o, it is already assimilated into another object.

Most of the data you want is available in HAL pins www.linuxcnc.org/docs/devel/html/man/man9/axis.9.html for example

Again it is a case of partial information can only illicit partial response.

If you share what it is you want to do, rather than asking how the method you have chosen can be made to work, without any overview of any of the other factors, you will get a better response and the answer may not be the one you thought of.

This is an open-source project, nothing you take from it can be claimed as copyright , so there is no need to be secretive about your own code, whilst happily taking whatever you want from the sources.

regards

DaBit wrote:

You can do that with a userspace HAL component. A userspace component can create pins which you can connect in HAL to the corresponding axis.N pins, and has access to all (?) userspace stuff such as the socket API. I wrote my first HAL-component last week, and I found it pretty simple even for a not-so-experienced programmer like myself.

See the 'comp' documentation for some more information.

So basically you write a component:

component datatowindows;
option userspace;

pin in float xaxis_pos;
pin in float xaxis_vel;
..
void userinit(argc,argv) {
ParseOptions (argc, argv);
SetupTCPLink();
}
..
void user_mainloop(void) {
while(1) {

FOR_ALL_INSTS() {
AsssemblePacket (&ourpacket, xaxis_pos, xaxis_vel, ...);
TransmitOverSocket (&ourpacket);
}
}
}

Then, in HAL;

loadusr -W datatowindows --destination=mywindowsmachine.lan:12345
net xpos axis.0.joint-pos-cmd => datatowindows.0.xaxis-pos
net ypos axis.1.joint-pos-cmd => datatowindows.0.yaxis-pos
...

tiffany wrote:

waw,
it's seems very interesting;
but why we couldn't use the data axis.0.joint-pos-cmd directly?

and I still could not understant how do you connect the pin datatowindows.0.xaxis-pos with xaxis_pos?？
could you tell me more details?

#include "rtapi.h"		/* RTAPI realtime OS API */
#include "rtapi_app.h"		/* RTAPI realtime module decls */
#include "hal.h"		/* HAL public API decls */
#include <float.h>
#include <rtapi_math.h>
#include <rtapi_string.h>

#include "gserver.h"

component datatowindows;
option userspace;

pin in double axis_pos;
pin in double axis_vel;


static int ini_gserver_init(void)
{
  int sockfd;
   
  sockfd = 0;
  sockfd = init_gserver();
  if (sockfd != 1) {
      rtapi_print_msg(RTAPI_MSG_ERR,"Unable to open socket\n");
    return 0;
    }

  rtapi_print_msg(RTAPI_MSG_ERR,"ini_gserver_init is run\n");

  return 1;
}


void user_mainloop(void) {

	ini_gserver_init();  //initial sockets;

	while(1) {

	char szdata[128] = {0};
        int joint_num;

	int num_joints = EMCMOT_MAX_JOINTS;

		for (joint_num = 0; joint_num < num_joints; joint_num++) {

		generate_formatted_data_int(szdata, joint_num, axis_pos, axis_vel);// data package
		send_data(szdata);// send data

		}
	}

}

DaBit wrote:

tiffany wrote:

waw,
it's seems very interesting;
but why we couldn't use the data axis.0.joint-pos-cmd directly?

Why can't you send an Ethernet frame to the NIC directly? That's just the way the software was designed.
It already starts with the fact that the motion controller runs in kernel space as RT process, and from there you don't have access to regular userspace stuff such as the socket API.

I suppose that if you put enough effort in it you can directly use the internal struct members of LinuxCNC, but why would you if a simple and clean method that also keeps working when LinuxCNC development progresses already exists?

and I still could not understant how do you connect the pin datatowindows.0.xaxis-pos with xaxis_pos?？
could you tell me more details?

Have a look at the various HAL tutorials.

In a nutshell: what HAL basically does is connecting 'black boxes' together with 'wires', just like you hook up your TV to your DVD player.
The 'black boxes' are the HAL components, the cables are 'nets'.

So we have a 'motion controller' box and a 'datatowindows' box. Now we must wire the two together with a cable. Just like you wire the DVD player's video out to the TV's video in.
So we stick a cable in the motioncontrollers 'joint 0 position out' socket, and plug it in the datatowindows 'joint 0 position in' socket. We do that 'cabling thing' like lthis:

net mycablename axis.0.joint-pos-cmd => datatowindows.0.xaxis-pos.


So, basically your job is to create a 'VCR' box that dumps it's data to Windows and hook it up in LinuxCNC. Much easier and cleaner than hacking into the motioncontroller

DaBit wrote:

Read the 'comp' documentation first, and have a look at the existing HAL component sources in the LinuxCNC source tree. That will answer a lot of questions.

Also, you might be able to get away using 'halsampler'/'sampler' and pipe it's output to NetCat. If that works for you there is no need to write any C code at all.

I must use the position and velocity of joints in c file;

so , any methods could help me get the data?

the data in HAL, I still could use it in C file?