ESP32 MASTER - ARDUINO NANO SLAVEs with IC MAX485 and MODBUS PROTOCOL

[FraRoberto]

Hello everyone, I have some communication problems between ESP32 and Arduino Nano via IC MAX485 and with the use of the Modbus protocol, I would like some help from you ESP32 experts.
I'll explain in detail where I have problems: I'm using a 38 PIN ESP32 WROOM 32 as Master in a project I made a couple of years ago with Arduino Nano V3. My initial project was to use Arduino nanos as slaves that were polled by another Arduino nano as masters. Now I would like to replace the Arduino nano Master with the ESP32 to have more performance.
I state that for me it is the first time that I use the ESP32, so forgive me the ignorance I show on this MCU.
Attached is what I've made at the moment on breadboard.... everything works except the communication between ESP32 and Arduino nano.

master_esp32_01.png (666.49 KiB) Viewed 1731 times

At the moment I'm testing the communication with only one slave, but actually the project has 4 slaves (all Arduino nano V3)
I am using Software Serial for serial communication. Below is the master's sketch.... in zip file..

thanks in advance to those who want to help me out.

[FraRoberto]

Is there really no one who can help me?

[ESP_Sprite]

Well, you're not asking a question, for one, so no one knows what you're in need of help with specifically.