libmodbus - reading from many slave_ids via RTU (expanded)

modbus-test-multi.c

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <modbus.h>

#include "timing.h"

#define SM4_ID  3
#define P120_ID 2
#define SM1_ID  1

#define MODE_SET_SLAVE 1
#define MODE_FLUSH     2
#define MODE_RECONNECT 3
#define MODE_MULTI_CTX 4

#define CURRENT_MODE MODE_FLUSH

#define  STR(x) #x
#define XSTR(x) STR(x)

int main(int argc, char *argv[])
{
    modbus_t *ctx;
#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_MULTI_CTX
    modbus_t *ctxs[4];
#endif
    uint16_t buf[4];
    uint8_t bits[0x25];
    int registers_address;

    int id_address[4] = {0, 7000, 7000, 4200};

    
    int i, nsteps = 2;
    int slave_id = MODBUS_BROADCAST_ADDRESS;
    useconds_t sleep_tick = 100, time_slept = 0;
    int rc;


    init_timers_main();
    printf("mode [%s] = %s\n", STR(CURRENT_MODE), XSTR(CURRENT_MODE));

#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_MULTI_CTX
    for (slave_id = SM1_ID; slave_id <= SM4_ID; slave_id++) {
	 main_start_timer();	 
	 ctxs[slave_id] = modbus_new_rtu("/dev/ttyUSB0", 9600, 'N', 8, 1);
	 if (ctxs[slave_id] == NULL) {
	      fprintf(stderr, "Unable to allocate libmodbus context %d: %s\n",
		      slave_id, modbus_strerror(errno));
	      return -1;
	 }

	 modbus_set_debug(ctxs[slave_id], FALSE);
	 modbus_set_slave(ctxs[slave_id], slave_id);
	 if (modbus_connect(ctxs[slave_id]) == -1) {
	      printf("Connection failed for %d: %s\n",
		     slave_id, modbus_strerror(errno));
	      return -1;
	 }
	 main_stop_timer();
	 printf("Created ctx = %p and connected [%d] in %f\n",
		ctxs[slave_id], slave_id, main_elapsed_time());
    }
#else /* !MODE_MULTI_CTX */
    ctx = modbus_new_rtu("/dev/ttyUSB0", 9600, 'N', 8, 1);
    if (ctx == NULL) {
        fprintf(stderr, "Unable to allocate libmodbus context\n");
        return -1;
    }
    modbus_set_debug(ctx, FALSE);
# if 0
    modbus_set_error_recovery(ctx,
                              MODBUS_ERROR_RECOVERY_LINK |
                              MODBUS_ERROR_RECOVERY_PROTOCOL);
    printf("modbus_set_error_recovery(ctx, LINK | PROTOCOL)\n");
# endif


    modbus_set_slave(ctx, SM4_ID);
    printf("slave_id = %d\n", SM4_ID);

    if (modbus_connect(ctx) == -1) {
	printf("Connection failed: %s\n",
	       modbus_strerror(errno));
	modbus_free(ctx);
	return -1;
    }
    printf("connected\n");
#endif /* !MODE_MULTI_CTX */

    printf("****************************************\n\n");

    slave_id = SM4_ID;
#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_MULTI_CTX
    ctx = ctxs[slave_id];
#else  /* !MODE_MULTI_CTX */
    modbus_set_slave(ctx, slave_id);
#endif /* !MODE_MULTI_CTX */
    
    registers_address = id_address[SM4_ID];
    memset(buf, 0, 4*sizeof(uint16_t));
    main_start_timer();
    if (modbus_read_registers(ctx, registers_address, 2, buf) == -1) {
	printf("Read failed (%d): %s\n",
	       slave_id, modbus_strerror(errno));
	printf("%4d = %04X %04X ???\n", registers_address, buf[0], buf[1]);
	goto close;
    }
    main_stop_timer();
    printf("modbus_read_registers(ctx = %p, %d, %d, %p) in %f sec\n",
	   ctx, registers_address, 2, buf,
	   main_elapsed_time());
    printf("Identyfikator SM4 [%d] (wyjscia binarne): 0x%04X 0x%04X (0x8C)\n\n",
	   slave_id, buf[0], buf[1]);

    printf("----------------------------------------\n\n");    
    sleep_tick = 10; /* msec */

#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_RECONNECT
    main_start_timer();
    modbus_close(ctx);
    main_stop_timer();
    printf("modbus_close(ctx) in %f sec\n", main_elapsed_time());
#endif
    slave_id = P120_ID;
#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_MULTI_CTX
    ctx = ctxs[slave_id];
#else  /* !MODE_MULTI_CTX */
    printf("modbus_set_slave(ctx, %d)", slave_id);
    fflush(stdout);
    main_start_timer();
    modbus_set_slave(ctx, slave_id);
    main_stop_timer();
    printf(" in %f sec\n", main_elapsed_time());
#endif /* !MODE_MULTI_CTX */
#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_RECONNECT
    main_start_timer();
    modbus_connect(ctx);
    main_stop_timer();
    printf("modbus_connect(ctx) in %f sec\n", main_elapsed_time());
#elif defined(CURRENT_MODE) && CURRENT_MODE == MODE_FLUSH
    main_start_timer();
    rc = modbus_flush(ctx);
    main_stop_timer();
    printf("modbus_flush(ctx) = %d in %f sec\n", rc, main_elapsed_time());
#endif

    registers_address = id_address[slave_id];
    for (i = 0; i < nsteps; i++) {
	 memset(buf, 0, 4*sizeof(uint16_t));
	 printf("modbus_read_registers(ctx = %p, %d, %d, %p)",
		ctx, registers_address, 2, buf);
	 fflush(stdout);
	 time_slept = 0;
	 main_start_timer();
	 while (modbus_read_registers(ctx, registers_address, 2, buf) == -1) {
	      usleep(sleep_tick);
	      time_slept += sleep_tick;

	      //printf(".");
	      //fflush(stdout);
	 }
	 main_stop_timer();
	 printf(" in %f sec\n", main_elapsed_time());
	 printf("wait: %d +/- %d msec (%d calls)\n",
		time_slept, sleep_tick, time_slept/sleep_tick + 1);
    }
    printf("Identyfikator P120 [%d] (przetwornik obrotow): 0x%04X 0x%04X (0x73)\n\n",
	   slave_id, buf[0], buf[1]);


#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_RECONNECT
    main_start_timer();
    modbus_close(ctx);
    main_stop_timer();
    printf("modbus_close(ctx) in %f sec\n", main_elapsed_time());
#endif
    slave_id = SM1_ID;
#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_MULTI_CTX
    ctx = ctxs[slave_id];
#else  /* !MODE_MULTI_CTX */
    printf("modbus_set_slave(ctx, %d)", slave_id);
    fflush(stdout);
    main_start_timer();
    modbus_set_slave(ctx, slave_id);
    main_stop_timer();
    printf(" in %f sec\n", main_elapsed_time());
#endif /* !MODE_MULTI_CTX */
#if defined(CURRENT_MODE) && CURRENT_MODE == MODE_RECONNECT
    main_start_timer();
    modbus_connect(ctx);
    main_stop_timer();
    printf("modbus_connect(ctx) in %f sec\n", main_elapsed_time());
#elif defined(CURRENT_MODE) && CURRENT_MODE == MODE_FLUSH
    main_start_timer();
    rc = modbus_flush(ctx);
    main_stop_timer();
    printf("modbus_flush(ctx) = %d in %f sec\n", rc, main_elapsed_time());
#endif

    registers_address = id_address[slave_id];
    for (i = 0; i < nsteps; i++) {
	 memset(buf, 0, 4*sizeof(uint16_t));
	 printf("modbus_read_registers(ctx = %p, %d, %d, %p)",
		ctx, registers_address, 2, buf);
	 fflush(stdout);
	 time_slept = 0;
	 main_start_timer();
	 while (modbus_read_registers(ctx, registers_address, 2, buf) == -1) {
	      usleep(sleep_tick);
	      time_slept += sleep_tick;

	      //printf(".");
	      //fflush(stdout);
	 }
	 main_stop_timer();
	 printf(" in %f sec\n", main_elapsed_time());
	 printf("wait: %d +/- %d msec (%d calls)\n",
		time_slept, sleep_tick, time_slept/sleep_tick + 1);
    }
    printf("Identyfikator SM1 [%d] (wejsc analogowych): 0x%04X 0x%04X (0x880x)\n\n",
	   slave_id, buf[0], buf[1]);



close:
    /* Close the connection */
    modbus_close(ctx);
    modbus_free(ctx);

    /* Free timers */
    done_timers_main();

    return 0;
}