iot modbus rtu set a new sensor address

RouterOS General
1

Hi,

how can I overwrite the factory default device ID with /iot modbus ?
For experimentation purposes, I acquired a cheap temperature and humidity sensor. I’m able to read all of its values without issue. However, in order to use more than one device simultaneously, I need to modify the default ID on the second sensor. Unfortunately, I haven’t been successful in doing so.

I tried follow the instructions from here, but I was not able to set the default device ID from 1 to 2 :frowning:

I’m sure I’m missing something, but after trying so many variations, I figured it’s better to just ask. :slight_smile:

/iot modbus transceive address=0x01 function=0x03 values=0x00,0x00,0x00,0x02 
   address: 1                  
  function: 3                  
      data: 010304021100F4     
    values: 529                
            244                
      time: 2025-05-31 19:59:57
    status: ok       
    
/iot modbus transceive address=0x01 function=0x06 values=0,1,0,2             
   address: 1                  
  function: 6                  
      data: 010600010002       
    values: 1                  
            0                  
            2                  
      time: 2025-05-31 20:07:12
    status: ok        
    
/iot modbus transceive address=0x01 function=0x03 values=0x00,0x00,0x00,0x02 
   address: 1                  
  function: 3                  
      data: 010304020E00F5     
    values: 526                
            245                
      time: 2025-05-31 20:14:25
    status: ok   
 
 /iot modbus transceive address=0x02 function=0x03 values=0x00,0x00,0x00,0x02 
failure: Timeout

SHT30_sensor_datasheet.pdf (605 KB)

2

From the datasheet the address register is at 0100H, so the write would have values=1,0,0,2 not values=0,1,0,2