ESP8266 - MAX3485 Modbus not getting data

Question

I'm trying to connect a modbus meter to a nodeMcu LoLin v3

I'm using a MAX3485 module to transfer the TTL to a RS485 connection. The modbus server has unitId 1, baud rate 9600 and no Parity

This is the scheme. A e B from the module go to the modbus server device Connection

And this is my simple script

#define DIRECTION D3
#include <ModbusRTU.h>
#include <SoftwareSerial.h>
SoftwareSerial S(D2, D1);
ModbusRTU mb;
bool cb(Modbus::ResultCode event, uint16_t transactionId, void* data) { // Callback to monitor errors
 if (event != Modbus::EX_SUCCESS) {
 Serial.print("Error result: 0x");
 Serial.println(event, HEX);
 
 } else {
 Serial.print("No Error");
 }
 return true;
}
void setup() {
 Serial.begin(115200);
 pinMode(DIRECTION, OUTPUT);
 digitalWrite(DIRECTION, 0);
 S.begin(9600, SWSERIAL_8N1);
 
 mb.begin(&S);
 
 mb.client();
}
void loop() {
 uint16_t res[2];
 if (!mb.slave()) { // Check if no transaction in progress
 mb.readHreg(1, 5, res, 1, cb); // Send Read Hreg from Modbus Server
 while (mb.slave()) { // Check if transaction is active
 mb.task();
 delay(10);
 
 }
 Serial.println("Res");
 Serial.println(res[0]);
 Serial.println(res[1]);
 
 }
 delay(1000);
}

I created a Software Serial on D1 and D2 and i'm trying to read from it but no matter what i do, i keep getting error 4 from the response and 2 values in my reg array i do not where they come from...

Error result: 0xE4
Res
59044
16382

Am I missing something? The modbus server works because i connected it to another client and everything is ok

• Majenko: If you're using a MAX3485 then VCC should be connected to 3.3V, not VIN (which on some boards cannot provide power but instead can only be used to power the board itself).
• Majenko: You might find my answer to this question enlightening...
• MarioC: i do not know if it's 3.3V or 5V... i put it on 3.3V on the ESP8266, nothing changes, it's still powered on