Hi again Jenna, I really don't know what I would do without your help hahaha. It seems that my fault is that in the void Setup I only initialized one port. Thanks to your code I have been able to see that it is necessary to do it with each and every one of them. Thank you very much for the help, now I can measure everything correctly, now I just have to calibrate and that's it :) thank you

with a portoboard if the 3 sensors work at the same time, then the failure is the multiplexer thank you very much, I hope they put an update or something to the library for q go headache that has given me hahaha. Thank you very much.

with a portoboard if the 3 sensors work at the same time, then the failure is the multiplexer thank you very much, I hope they put an update or something to the library for q go headache that has given me hahaha. Thank you very much.

Here is an image of what I get in the terminal. The voltage is correct but the current is not.Sorry for the inconvenience 

Hey, thanks for the link, I have been reading and something similar happens to me, since the sensors (with different addresses x45, x44 and x41) separately work fine. But when I put them all in the multiplexer they go crazy. I don't see what I'm doing wrong. Here I leave an example of the answers, (the voltage reads well but the current does not).

Hey, I have seen your message, in my case I have a single multiplexer and 3 sensors (Wattmeter) with 3 different I2C addresses (x45, x44 and x41). Separately they work without problem, the thing is that when I put the 3 together they go crazy, the voltage gives me well but the current does not. The wiring and the equipment I want to measure is correct, the problem is in my code but I do not see the error.  What can I do?I also tried the advice you gave me to select port 8 before switching to another port.

I got it, thank you very much for your help, you are an angel :)

thanks for the code, but, unfortunately I still have the same error, many .txt are generated but in none of them is written "hello word". The pins used have been , VCC->5V GND->GND RX->18 (in Arduino mega is Tx) and S->6. I have also tried to take a digital pin (pin 50) and try with that but still the same problem.

Yeah, here you are,  as I say above is an example code that gives me dfrobot but in this case all it does is generate many .txt, what I need is to write data in them and we don't know how to do it:#define SPIN 6  //Connect to the module Pin S, trigger to save files at low level  uint16_t i = 0; void setup(void) {  Serial.begin(9600);  delay(2000);  //To aviod data lost, delay a period of time to wait for the module to start  pinMode(SPIN, OUTPUT);   digitalWrite(SPIN, HIGH); } void loop(void) {  Serial.println(String(i));  i++;  if((i % 10) == 0){    digitalWrite(SPIN, LOW);    delay(500);    digitalWrite(SPIN, HIGH);  }   delay(300); }

The  problem is that the SD ligth blink once, but nothing is generate. I follow all the steps one by one I think. Thanks for the answer.