tobiasfaust
commented
1 year ago Hi Steve,
thanks for your very useful hints. I will try to answer: 1) RX/TX Pins: I will add this in the next version, start of next year. In normal cases you are using an ESP32 with no other tasks so all pins are free ;) 2) common ground: i most cases the ground connection is not needed. The same for my case. It was not needed 3) direction pin: I have this RS-485 module: HW-0519 -> https://tasmota.github.io/docs/SolaX-X1/#breakout-boards This boards controls the direction by itself. But you are right, i will add the possibility of declaring a direction pin in next version 4) the possibility to send write requests sound really good. In my case the most wanted functionality was to read the values simply. I will add this functionality too in next release. I think its not difficult. But you can help my by find out the most wanted setting-functions with their registers and hex request. best regards
uham999
I recently discovered your SolaxModbusGateway work. I congratulate you on your very interesting high quality work. Based on my experience trying to use this tool, I have a number of suggestions for you that if implemented would make it easier to use. In the modbus::init() function it would be useful to be able to set the serial2 RX and TX pins using private class variables in modbus.h to set the pins. On the ESP32 board I use, the default pins for Serial2 are in use for other purposes so the default pins can't be used. For example in modbus.cpp :- Serial2.begin(this->Baudrate,SERIAL_8N1,this->RXpin,this->TXpin);
Another problem I noticed was the documentation as written for setting up the RS485 Invertor suggests the following connections RS485 Inverter
A -> Pin 4 B -> Pin 5
In reality, the Inverter and the ESP32 have to have a common ground so the ESP32 Gnd needs to connect to the Solax inverter Gnd otherwise it will not work at all or not reliably. I could be wrong but I didn't see anything saying that this is the case. GND on the Solax X1-Hybrid is pin 6 according to page 61 in the user manual for it. RS485 Inverter
A -> Pin 4 B -> Pin 5 GND -> Pin 6 Solax X1 Hybrid
Another thing I noticed is that you do not use an RS485 direction control pin. I'm not sure why it works in your situation without it. It doesn't work with the RS485 breakout board that I used because there is no direction control. Although I have been using microcontrollers for a long time, RS485 is new to me so there could be something that I don't understand. On the TTL to RS485 breakout board I have, it is necessary to set the direction control pin correctly. In simple test programs it works well using the direction pin. If I don't use the direction pin, it doesn't work. For your configuration I can only assume that you use a special board that automatically handles the direction for you? It would be useful if it could be programmed to work with a more basic RS485 board. The RS485 board I have is shown on this page :- https://microcontrollerslab.com/rs485-serial-communication-esp32-esp8266-tutorial/ In my case, I connect the RE and DE pins together and connect them to a direction pin on the ESP32. Whenever you want to transmit the program takes to direction pin HIGH and when receiving data, put the direction pin LOW. One I use the direction pin in test programs, then transferring data between two ESP32 devices is straight forward.
In your test application test_RS485_Solax_ESP32.INO, you have comments that looks like you have tried something like this. //#define RX 17 // D1 =5 // 10 //Serial Receive pin //#define TX 16 // D2 = 4 //Serial Transmit pin //#define RTS_pin 9 //RS485 Direction control //#define RS485Transmit HIGH //#define RS485Receive LOW
The final suggestion I have is that an implementation writing to the Solax X1 Hybrid write registers from MQTT would be very useful for my application and maybe for other people. I have to keep a number of inverters synchronized with the same configuration so having each ESP32 subscribe to an MQTT topic so it can receive a configuration from the MQTT broker would be a useful function. The ESP32 could then write changes to the inverter registers.
I can potentially help with work like this because I have reasonable programming skills although I have never used GitHub before. regards Steve