Zephyr Modbus RTU "Frame Error"

RE: Zephyr Modbus RTU "Frame Error"

Sigurd Hellesvik — Fri, 16 Aug 2024 07:46:34 GMT

I don't have complete overview over this specific module I must admit. This means I will need some more context to be able to help.

[quote user="RonVo"]I got it received the data now.[/quote]

What did you do to fix this?

[quote user="RonVo"] However I'm not about to transmit. [/quote]

Any errors?

RE: Zephyr Modbus RTU "Frame Error"

RonVo — Thu, 15 Aug 2024 18:33:46 GMT

I got it received the data now. However I'm not about to transmit. I connect the B- to Uart Tx but seem like it doesn't work that way. Is there any way I can transmit rs-485 without transceiver?

RE: Zephyr Modbus RTU "Frame Error"

Sigurd Hellesvik — Thu, 15 Aug 2024 14:18:54 GMT

I see that you get the error message "FC16 failed with -116". From errno.h this looks like EHOSTDOWN.
Try to check when modbus_write_holding_regs returns this error?

RE: Zephyr Modbus RTU "Frame Error"

RonVo — Wed, 14 Aug 2024 18:17:03 GMT

SDK Version: Zephyr version: 3.7.0-rc2
Full log of device:
[00:00:00.249,450] <inf> modbus_serial: RTU timeout 2005 us
[00:00:00.250,579] <wrn> modbus: Client wait-for-RX timeout
[00:00:00.250,579] <err> mbc_sample: FC16 failed with -116
[00:00:00.281,921] <wrn> modbus_serial: Frame length error
This is my code:

 */
#include <zephyr/kernel.h>
#include <zephyr/sys/util.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/modbus/modbus.h>
#include <zephyr/logging/log.h>

/* 1000 msec = 1 sec */
#define SLEEP_TIME_MS   1000

LOG_MODULE_REGISTER(mbc_sample, LOG_LEVEL_INF);
/* The devicetree node identifier for the "led0" alias.*/

static int client_iface;

const static struct modbus_iface_param client_param = {
    .mode = MODBUS_MODE_RTU,
    .rx_timeout = 1000,
    .serial = {
        .baud = 19200,
        .parity = UART_CFG_PARITY_EVEN,
        .stop_bits_client = UART_CFG_STOP_BITS_1,
    },  
};

#define MODBUS_NODE DT_COMPAT_GET_ANY_STATUS_OKAY(zephyr_modbus_serial)

static int init_modbus_client(void)
{
    const char iface_name[] = {DEVICE_DT_NAME(MODBUS_NODE)};

    client_iface = modbus_iface_get_by_name(iface_name);

    return modbus_init_client(client_iface, client_param);
}

int main(void)

{
    uint16_t holding_reg[8] = {'H', 'e', 'l', 'l', 'o'};
    const uint8_t coil_qty = 3;
    uint8_t coil[1] = {0};
    const int32_t sleep = 3000;
    static uint8_t node = 1;
    int err;
    uint8_t received[10];

    if (init_modbus_client()) {
        LOG_ERR("Modbus RTU client initialization failed");
        return 0;
    }

    err = modbus_write_holding_regs(client_iface, node, 0, holding_reg,
                    ARRAY_SIZE(holding_reg));
    if (err != 0) {
        LOG_ERR("FC16 failed with %d", err);
    }



}

RE: Zephyr Modbus RTU "Frame Error"

Sigurd Hellesvik — Wed, 14 Aug 2024 10:29:36 GMT

Hi,

For us to help you with this in the best possible way, please list the following information:

SDK Version
Which sample do you use, if any?
Do you use custom code?
What is the full log from the device?

Regards,
Sigurd Hellesvik