connection of multiple slaves

Good morning everyone, let me briefly explain the problem I have, I would like to use two devices to read and write information from a controller. The problem and the following, I would like to use both Arduino to read and the original screen of the controller, how can I do to use both? I can only control the module of Arduino, the screen continues to require information ...

How do I pause the external module to communicate with the Arduino?

Are there any solutions or do I have to decide which one to use?

Mystery controller, mystery Arduino(s?), mystery module(s?). Not sure how to help.

What are those parts? How are they connected? A schematic would be welcome.

Then the controller is a tracer2215bn with the respective MT50 screen. The arduino I use is a Mega, with the RS485 to read the data buses that sends the controller.
I would like to use both the screen and the RS485 simultaneously to read the data. The MT50 continues to receive and send data to be able to view all the data in real time, the problem arises when I want to request data with Arduino, I should pause the MT50, request information with Arduino and then restart the MT50.

How can I “stop” the communication of the MT50?

In link I put the scheme that I would like to achieve, Good day to all

How can I "stop" the communication of the MT50?

There is still not enough information to enable us to understand how the communication works - so how can we know whether or how it can be stopped.

What is a "tracer2215bn"
What is an MT50
What do they do?
What data passes between them?
What is the proposed role of the Arduino in all of this?


PS ... Please display your image(s) in your post so we can see it(them) without downloading it(them). See this Simple Image Guide

How does SPI (your image) relate to RS485 (your device)?

I think that we’re talking about this? Please post a (working) link to the datasheets / user manuals of tracer2215bn and MT50; googling and following the links often results in 404 errors.

This is the communication protocol:

With this program I can view the data:

#include <ModbusMaster.h>

#define MAX485_DE     3
#define MAX485_RE_NEG 2// Arduino uno 3,2 Arduino mega 10,11

ModbusMaster node;
 void preTransmission()
  digitalWrite(MAX485_RE_NEG, 1);
  digitalWrite(MAX485_DE, 1);

 void postTransmission()
  digitalWrite(MAX485_RE_NEG, 0);
  digitalWrite(MAX485_DE, 0);

void setup() {
  pinMode(MAX485_RE_NEG, OUTPUT);
  pinMode(MAX485_DE, OUTPUT);
  digitalWrite(MAX485_RE_NEG, 0);
  digitalWrite(MAX485_DE, 0);

  node.begin(1, Serial);


void loop() {
  uint8_t resultMain;
  resultMain = node.readInputRegisters(0x3100, 20);
  if(resultMain == node.ku8MBSuccess)
    Serial.print("Charging equipment input voltage: ");
    Serial.println(node.getResponseBuffer(0x00) / 100.0f); 
    Serial.print("Charging equipment input current: ");
    Serial.println(node.getResponseBuffer(0x01) / 100.0f); 
    Serial.print("Charging equipment input Power: ");
    Serial.println(node.getResponseBuffer(0x02) / 100.0f);  
    Serial.print("Charging equipment Output voltage: ");
    Serial.println(node.getResponseBuffer(0x04) / 100.0f);
    Serial.print("Charging equipment Output Current: ");
    Serial.println(node.getResponseBuffer(0x05) / 100.0f); 
    Serial.print("Charging equipment Output Power: ");
    Serial.println(node.getResponseBuffer(0x06) / 100.0f);  
    Serial.print("Disharging equipment output voltage: ");
    Serial.println(node.getResponseBuffer(0x0C) / 100.0f); 
    Serial.print("Disharging equipment output curent: ");
    Serial.println(node.getResponseBuffer(0x0D) / 100.0f); 
    Serial.print("Disharging equipment output Power: ");
    Serial.println(node.getResponseBuffer(0x0E) / 100.0f);
    Serial.print("Battery Temperature: ");
    Serial.println(node.getResponseBuffer(0x10) / 100.0f); 
    Serial.print("Temperature inside equipment:  ");
    Serial.println(node.getResponseBuffer(0x11) / 100.0f); 
    Serial.print("Power components temperature: ");
    Serial.println(node.getResponseBuffer(0x12) / 100.0f);

I would like to use both Arduino and this screen (original of my controller):

I can’t connect them both because if not there are problems with data management…

How can I check and pause my MT50 to read data with Arduino?

I am not familiar with Modbus However it comes up fairly often in the Forum and I suspect you will get a better response if you modify your Original Post and edit your Title so it mentions that you are using Modbus