449d2a6367
Contains two different component folders per each implementation (serial_master and serial_slave) with concrete ports. Added common public api for master and slave and common interface for master and slave implementation. Add support of cmake system (added cmake files). Added sdkconfig.defaults files for slave and master modbus examples. Updated make file and KConfig for freemodbus component Update according to review and fix doxygen warnings Fix Doxyfile to pass documentation build Update headers and change interface file names as per review comments Merge branch feature/freemodbus_move_rs485_mode_control Update after review: The stack modbus folder updated to support master and slave ports together and moved into freemodbus/modbus Stack and port files updated to remove duplicated simbols Make file, KConfig and CMakeLists.txt updated to compile master and slave stacks, common interface and concrete implementations of ports Stack callback functions execute callbacks using interface pointer from concrete port implementation User can instantiate any of concrete port using common API (only one concrete port at a time) and it does not require to select port by KConfig Port pins and mode configuration moved into example files from port files to allow user select pins and port mode (customer request) Changes tested using pymodbus, ModbusPoll and communication between two boards Updated DoxyFile according to public include path Fix maximum instance size for slave (merge from master of customer issue) Fix critical section issue TW#28622 (change spin lock based critical section to semaphore) Move serial port files into component port folder for master and slave accordingly Fix example issue showed in the log when IO slave is not configured correctly Fix conflicts while merging from origin/master Fix errors handling in modbus controller interface + some final corrections according to review Update maximum allowed number of slaves in the network segment Fix bug with incorrect coils read mask Closes https://github.com/espressif/esp-idf/issues/858 |
||
|---|---|---|
| .. | ||
| main | ||
| CMakeLists.txt | ||
| Makefile | ||
| README.md | ||
| sdkconfig.defaults | ||
README.md
Modbus Slave Example
This example demonstrates using of FreeModbus stack port implementation for ESP32. The external Modbus host is able to read/write device parameters using Modbus protocol transport. The parameters accessible thorough Modbus are located in deviceparams.h/c files and can be updated by user. These are represented in structures holding_reg_params, input_reg_params, coil_reg_params, discrete_reg_params for holding registers, input parameters, coils and discrete inputs accordingly. The app_main application demonstrates how to setup Modbus stack and use notifications about parameters change from host system. The FreeModbus stack located in components\freemodbus\ folder and contain \port folder inside which contains FreeModbus stack port for ESP32. There are some parameters that can be configured in KConfig file to start stack correctly (See description below for more information).
Hardware required :
PC + USB Serial adapter connected to USB port + RS485 line drivers + ESP32 WROVER-KIT board. The MAX485 line driver is used as an example below but other similar chips can be used as well.
RS485 example circuit schematic:
VCC ---------------+ +--------------- VCC
| |
+-------x-------+ +-------x-------+
RXD <------| RO | DIFFERENTIAL | RO|-----> RXD
| B|---------------|B |
TXD ------>| DI MAX485 | \ / | MAX485 DI|<----- TXD
ESP32 WROVER KIT 1 | | RS-485 side | | Modbus master
RTS --+--->| DE | / \ | DE|---+
| | A|---------------|A | |
+----| /RE | PAIR | /RE|---+-- RTS
+-------x--------+ +-------x-------+
| |
--- ---
How to setup and use an example:
Configure the application
Configure the UART pins used for modbus communication using command and table below.
make menuconfig
-----------------------------------------------------------------------------------
| ESP32 Interface | #define | Default ESP32 Pin | External RS485 |
| ----------------------|--------------------|-------------------| Driver Pin |
| Transmit Data (TxD) | CONFIG_MB_UART_TXD | GPIO23 | DI |
| Receive Data (RxD) | CONFIG_MB_UART_RXD | GPIO22 | RO |
| Request To Send (RTS) | CONFIG_MB_UART_RTS | GPIO18 | ~RE/DE |
| Ground | n/a | GND | GND |
-----------------------------------------------------------------------------------
The communication parameters below allow to configure freemodbus stack appropriately but usually it is enough to use default settings. See the help string of parameters for more information.
Setup external Modbus master software
Configure the external Modbus master software according to port configuration parameters used in application. As an example the Modbus Poll application can be used with this example.
Build and flash software
Build the project and flash it to the board, then run monitor tool to view serial output:
make -j4 flash monitor
(To exit the serial monitor, type Ctrl-].)
See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
Example Output
Example output of the application:
INPUT READ: time_stamp(us):565240387, mb_addr:1, type:8, st_address:0x3ffb385c, size:8
HOLDING READ/WRITE: time_stamp(us):12104081, mb_addr:1, type:2, st_address:0x3ffb386c, size:8
The output lines describe type of operation, its timestamp, modbus address, access type, storage address in parameter structure and number of registers accordingly.