Modbus slave byte ordering

[Delffiini]

Hi,

I made ModbusTCP slave based on the esp-idf examples.

It works but the floating point byte order is not understood by the connected Modbus master.

I need to make an extra data array just for the Modbus data transfer. Is there any way just change the byte order in esp-idf Modbus library?

This is my solution at the moment:

Code: [Select all] [Expand/Collapse]

1. void DataExchange::updateModbusArray()
2. {
3.     for(int i=0; i < _numElements; i++)
4.     {
5.         _modbusArray[i*4+0] = *((char*)_dataArray + i*4+2);
6.         _modbusArray[i*4+1] = *((char*)_dataArray + i*4+3);
7.         _modbusArray[i*4+2] = *((char*)_dataArray + i*4+0);
8.         _modbusArray[i*4+3] = *((char*)_dataArray + i*4+1);
9.     }
10. }

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BR, Ilkka

[MicroController]

Is there any way just change the byte order in esp-idf Modbus library?

There may be, cf. viewtopic.php?f=2&t=23040

[Delffiini]

Hi,I cannot edit the esp-idf managed component directly. Is there any other way..?

Just mean the function :

Code: Select all

static esp_err_t mbc_serial_master_get_parameter(uint16_t cid, char* name, uint8_t* value_ptr, uint8_t *type)