Add Modbus TCP

OpenDTU is extended by a Modbus server. The Modbus server serves TCP at port 502.
At Modbus ID 1 the server mimicks the Modbus registers in the original DTUPro.
At Modbus ID 125 the server serves a SunSpec compatible pseudo inverter that
provides the OpenDTU aggregated data from all registered inverters.

The OpenDTU Modbus sources were imspired by : https://github.com/ArekKubacki/OpenDTU.
See tbnobody#582 for the orignal pull request.

The Modbus library used for Modbus communication is: https://github.com/eModbus/eModbus.
Documentation for the library is here: https://emodbus.github.io/.
The library was choosen to achieve a lower memory footprint.

fixes tbnobody#582

Signed-off-by: Bobby Noelte <[email protected]>

include/Configuration.h

@@ -82,6 +82,12 @@ struct CONFIG_T {
         double Latitude;
         uint8_t SunsetType;
     } Ntp;
+    struct {
+        bool TCPEnabled;
+        uint32_t Port;
+        uint32_t IDDTUPro;
+        uint32_t IDTotal;
+    } Modbus;
 
     struct {
         bool Enabled;

include/ModbusDtu.h

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+#include <TaskSchedulerDeclarations.h>
+
+// eModbus
+#include "ModbusServerTCPasync.h"
+
+class ModbusDtuClass {
+public:
+    ModbusDtuClass();
+    void init(Scheduler& scheduler);
+
+private:
+    void loop();
+
+    Task _loopTask;
+};
+
+ModbusMessage OpenDTUTotal(ModbusMessage request);
+ModbusMessage DTUPro(ModbusMessage request);
+
+extern ModbusDtuClass ModbusDtu;
+extern ModbusServerTCPasync ModbusTCPServer;

include/ModbusSettings.h

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+class ModbusSettingsClass {
+public:
+    ModbusSettingsClass();
+    void init();
+
+    void performConfig();
+
+private:
+    void startTCP();
+
+    void stopTCP();
+};
+
+extern ModbusSettingsClass ModbusSettings;

include/WebApi.h

@@ -12,6 +12,7 @@
 #include "WebApi_inverter.h"
 #include "WebApi_limit.h"
 #include "WebApi_maintenance.h"
+#include "WebApi_modbus.h"
 #include "WebApi_mqtt.h"
 #include "WebApi_network.h"
 #include "WebApi_ntp.h"
@@ -55,6 +56,7 @@ class WebApiClass {
     WebApiInverterClass _webApiInverter;
     WebApiLimitClass _webApiLimit;
     WebApiMaintenanceClass _webApiMaintenance;
+    WebApiModbusClass _webApiModbus;
     WebApiMqttClass _webApiMqtt;
     WebApiNetworkClass _webApiNetwork;
     WebApiNtpClass _webApiNtp;

include/WebApi_modbus.h

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+#include <ESPAsyncWebServer.h>
+#include <TaskSchedulerDeclarations.h>
+
+class WebApiModbusClass {
+public:
+    void init(AsyncWebServer& server, Scheduler& scheduler);
+
+private:
+    void onModbusStatus(AsyncWebServerRequest* request);
+    void onModbusAdminGet(AsyncWebServerRequest* request);
+    void onModbusAdminPost(AsyncWebServerRequest* request);
+};

include/defaults.h

@@ -30,6 +30,11 @@
 #define NTP_LATITUDE 51.1657f
 #define NTP_SUNSETTYPE 1U
 
+#define MODBUS_TCP_ENABLED false
+#define MODBUS_PORT 502
+#define MODBUS_ID_DTUPRO 1
+#define MODBUS_ID_TOTAL 125
+
 #define MQTT_ENABLED false
 #define MQTT_HOST ""
 #define MQTT_PORT 1883U

platformio.ini

@@ -36,10 +36,17 @@ build_flags =
 build_unflags =
     -std=gnu++11
 
+; Ignore dependencies of eModbus as they are fulfilled by other library variants
+lib_ignore =
+    AsyncTCP
+    ESPAsyncTCP
+    custom-Ethernet
+
 lib_deps =
     mathieucarbou/ESP Async WebServer @ 2.9.0
     bblanchon/ArduinoJson @ ^7.0.4
     https://github.com/bertmelis/espMqttClient.git#v1.6.0
+    https://github.com/eModbus/eModbus.git
     nrf24/RF24 @ ^1.4.8
     olikraus/U8g2 @ ^2.35.15
     buelowp/sunset @ ^1.1.7

src/Configuration.cpp

@@ -54,6 +54,12 @@ bool ConfigurationClass::write()
     ntp["longitude"] = config.Ntp.Longitude;
     ntp["sunsettype"] = config.Ntp.SunsetType;
 
+    JsonObject modbus = doc["modbus"].to<JsonObject>();
+    modbus["tcp_enabled"] = config.Modbus.TCPEnabled;
+    modbus["port"] = config.Modbus.Port;
+    modbus["id_dtupro"] = config.Modbus.IDDTUPro;
+    modbus["id_total"] = config.Modbus.IDTotal;
+
     JsonObject mqtt = doc["mqtt"].to<JsonObject>();
     mqtt["enabled"] = config.Mqtt.Enabled;
     mqtt["hostname"] = config.Mqtt.Hostname;
@@ -227,6 +233,12 @@ bool ConfigurationClass::read()
     config.Ntp.Longitude = ntp["longitude"] | NTP_LONGITUDE;
     config.Ntp.SunsetType = ntp["sunsettype"] | NTP_SUNSETTYPE;
 
+    JsonObject modbus = doc["modbus"];
+    config.Modbus.TCPEnabled = modbus["tcp_enabled"] | MODBUS_TCP_ENABLED;
+    config.Modbus.Port = modbus["port"] | MODBUS_PORT;
+    config.Modbus.IDDTUPro = modbus["id_dtupro"] | MODBUS_ID_DTUPRO;
+    config.Modbus.IDTotal = modbus["id_total"] | MODBUS_ID_TOTAL;
+
     JsonObject mqtt = doc["mqtt"];
     config.Mqtt.Enabled = mqtt["enabled"] | MQTT_ENABLED;
     strlcpy(config.Mqtt.Hostname, mqtt["hostname"] | MQTT_HOST, sizeof(config.Mqtt.Hostname));