Modbus Slave and master on arduino

Hello everyone faced such a problem, there are two arduino, configure the modbus protocol, I encountered that the master sends requests to the slave, but slave does not receive them.
Connected via rs485, RE DE pins are connected via 8 pin.
With EASYtransfer library everything works, but modbus is needed
Master

/**
 *  Modbus master example 1:
 *  The purpose of this example is to query an array of data
 *  from an external Modbus slave device. 
 *  The link media can be USB or RS232.
 *
 *  Recommended Modbus slave: 
 *  diagslave http://www.modbusdriver.com/diagslave.html
 *
 *  In a Linux box, run 
 *  "./diagslave /dev/ttyUSB0 -b 19200 -d 8 -s 1 -p none -m rtu -a 1"
 * 	This is:
 * 		serial port /dev/ttyUSB0 at 19200 baud 8N1
 *		RTU mode and address @1
 */

#include <ModbusRtu.h>

// data array for modbus network sharing
uint16_t au16data[16];
uint8_t u8state;

/**
 *  Modbus object declaration
 *  u8id : node id = 0 for master, = 1..247 for slave
 *  u8serno : serial port (use 0 for Serial)
 *  u8txenpin : 0 for RS-232 and USB-FTDI 
 *               or any pin number > 1 for RS-485
 */
Modbus master(0,0,8); // this is master and RS-232 or USB-FTDI

/**
 * This is an structe which contains a query to an slave device
 */
modbus_t telegram;

unsigned long u32wait;

void setup() {
  master.begin( 19200 ); // baud-rate at 19200
  master.setTimeOut( 2000 ); // if there is no answer in 2000 ms, roll over
  u32wait = millis() + 1000;
  u8state = 0; 
 
}

void loop() {
  switch( u8state ) {
  case 0: 
    if (millis() > u32wait) u8state++; // wait state
    break;
  case 1: 
    telegram.u8id = 5; // slave address
    telegram.u8fct = 3; // function code (this one is registers read)
    telegram.u16RegAdd = 1; // start address in slave
    telegram.u16CoilsNo = 4; // number of elements (coils or registers) to read
    telegram.au16reg = au16data; // pointer to a memory array in the Arduino

    master.query( telegram ); // send query (only once)
    u8state++;
   
    break;
  case 2:
    master.poll(); // check incoming messages
  
    if (master.getState() == COM_IDLE) {
      u8state = 0;
       Serial.println(au16data[0]);
      u32wait = millis() + 100; 
    }
    break;
    
  }
}

Slave

/**
 *  Modbus slave example 2:
 *  The purpose of this example is to link a data array
 *  from the Arduino to an external device.
 *
 *  Recommended Modbus Master: modpoll
 *  http://www.modbusdriver.com/modpoll.html
 */

#include <ModbusRtu.h>

// data array for modbus network sharing
uint16_t au16data[16] = {
  3, 1415, 9265, 4, 2, 7182, 28182, 8, 0, 0, 0, 0, 0, 0, 1, -1 };

/**
 *  Modbus object declaration
 *  u8id : node id = 0 for master, = 1..247 for slave
 *  u8serno : serial port (use 0 for Serial)
 *  u8txenpin : 0 for RS-232 and USB-FTDI 
 *               or any pin number > 1 for RS-485
 */
Modbus slave(5,0,8); // this is slave @1 and RS-232 or USB-FTDI

void setup() {

slave.begin( 19200); // 19200 baud, 8-bits, even, 1-bit stop
}

void loop() {
  slave.poll( au16data, 16 );


}
       Serial.println(au16data[0]);

It's a bad idea to print anything into the ModBus channel. Even if the RS-485 driver is not activated you shouldn't do that.

Modbus slave(5,0,8); // this is slave @1 and RS-232 or USB-FTDI

The comment doesn't reflect what the code is doing.

master sends requests to the slave, but slave does not receive them.

How do you know?

Post a wiring diagram (may be hand drawn)!

What Arduino models are used?