ModbusTCP to ModbusRTU example added

Author: emelianov

examples/Bridge/README.md

@@ -1,17 +1,21 @@
 # Bridge functions
 
-## Basic
+## [Basic](basic/basic.ino)
 
 Basic 'Bridge'. Indeed this sample pulling data from Modbus Server and stores it to local registers. Local registers can be accessed via Modbus Client instance that running aside.
 
-## True
+## [ModbusRTU to ModbusTCP bridge](true/true.ino)
 
 Fullfunctional ModbusRTU to ModbusTCP bridge.
 
-## MultipeServerID
+## [Multiple Server ID](MultipeServerID/MultipeServerID.ino)
 
 Respond for multiple ModbusRTU IDs from single device
 
+## [ModbusTCP to Modbus RTU Simulator](TCP-to-RTU-Simulator/TCP-to-RTU-Simulator.ino)
+
+Fullfunctional ModbusTCP to ModbusRTU bridge with on-device ModbusRTU simulator
+
 ```c
 uint16_t rawRequest(id_ip, uint8_t* data, uint16_t len, cbTransaction cb = nullptr, uint8_t unit = MODBUSIP_UNIT);
 uint16_t rawResponce(id_ip, uint8_t* data, uint16_t len, uint8_t unit = MODBUSIP_UNIT);
@@ -22,7 +26,12 @@ uint16_t errorResponce(id_ip, Modbus::FunctionCode fn, Modbus::ResultCode excode
 - `len` Byte count to send
 - `unit` UnitId (ModbusTCP/TLS only)
 - `fn` function code in responce
-- `excode` Exceprion code in responce
+- `excode` Exception code in responce
+
+```c
+uint16_t setTransactionId(uint16_t id);
+```
+- `id` Value to replace transaction id sequence (ModbusTCP/TLS only)
 
 ```c
 union frame_arg_t {

examples/Bridge/TCP-to-RTU-Simulator/TCP-to-RTU-Simulator.ino

@@ -0,0 +1,134 @@
+/*
+  ModbusRTU ESP8266/ESP32
+  ModbusTCP to ModbusRTU bridge with on-device ModbusRTU simulator
+*/
+#ifdef ESP8266
+ #include <ESP8266WiFi.h>
+#else //ESP32
+ #include <WiFi.h>
+#endif
+#include <ModbusTCP.h>
+#include <ModbusRTU.h>
+//#include <SoftwareSerial.h>
+//SoftwareSerial S(13, 15);
+#include <StreamBuf.h>
+#define BSIZE 1024
+uint8_t buf1[BSIZE];
+uint8_t buf2[BSIZE];
+StreamBuf S1(buf1, BSIZE);
+StreamBuf S2(buf2, BSIZE);
+DuplexBuf P1(&S1, &S2);
+DuplexBuf P2(&S2, &S1);
+ModbusRTU sym;
+
+int DE_RE = 2;
+
+ModbusRTU rtu;
+ModbusTCP tcp;
+
+IPAddress srcIp;
+
+
+uint16_t transRunning = 0;  // Currently executed ModbusTCP transaction
+uint8_t slaveRunning = 0;   // Current request slave
+ 
+bool cbTcpTrans(Modbus::ResultCode event, uint16_t transactionId, void* data) { // Modbus Transaction callback
+  if (event != Modbus::EX_SUCCESS)                  // If transaction got an error
+    Serial.printf("Modbus result: %02X, Mem: %d\n", event, ESP.getFreeHeap());  // Display Modbus error code (222527)
+  if (event == Modbus::EX_TIMEOUT) {    // If Transaction timeout took place
+    tcp.disconnect(tcp.eventSource());          // Close connection
+  }
+  return true;
+}
+
+bool cbRtuTrans(Modbus::ResultCode event, uint16_t transactionId, void* data) {
+    if (event != Modbus::EX_SUCCESS)                  // If transaction got an error
+      Serial.printf("Modbus result: %02X, Mem: %d\n", event, ESP.getFreeHeap());  // Display Modbus error code (222527)
+    return true;
+}
+
+
+// Callback receives raw data 
+Modbus::ResultCode cbTcpRaw(uint8_t* data, uint8_t len, void* custom) {
+  auto src = (Modbus::frame_arg_t*) custom;
+  
+  Serial.print("TCP IP: ");
+  Serial.print(IPAddress(src->ipaddr));
+  Serial.printf(" Fn: %02X, len: %d \n\r", data[0], len);
+
+  if (transRunning) { // Note that we can't process new requests from TCP-side while waiting for responce from RTU-side.
+    tcp.setTransactionId(transRunning); // Set transaction id as per incoming request
+    tcp.errorResponce(src->ipaddr, (Modbus::FunctionCode)data[0], Modbus::EX_SLAVE_DEVICE_BUSY);
+    return Modbus::EX_SLAVE_DEVICE_BUSY;
+  }
+
+  rtu.rawRequest(slaveRunning, data, len, cbRtuTrans);
+  
+  if (src->unitId) {
+    tcp.setTransactionId(transRunning); // Set transaction id as per incoming request
+
+    //uint16_t succeed = tcp.rawResponce(src->ipaddr, data, len, slaveRunning);
+
+    tcp.errorResponce(src->ipaddr, (Modbus::FunctionCode)data[0], Modbus::EX_ACKNOWLEDGE);
+    return Modbus::EX_ACKNOWLEDGE;
+  }
+  
+  srcIp = src->ipaddr;
+  
+  slaveRunning = src->slaveId;
+  
+  transRunning = src->transactionId;
+  
+  return Modbus::EX_SUCCESS;  
+  
+}
+
+
+// Callback receives raw data from ModbusTCP and sends it on behalf of slave (slaveRunning) to master
+Modbus::ResultCode cbRtuRaw(uint8_t* data, uint8_t len, void* custom) {
+  auto src = (Modbus::frame_arg_t*) custom;
+  tcp.setTransactionId(transRunning); // Set transaction id as per incoming request
+  uint16_t succeed = tcp.rawResponce(srcIp, data, len, slaveRunning);
+  if (!succeed){
+    Serial.print("fail");
+  }
+  Serial.printf("RTU Slave: %d, Fn: %02X, len: %d, ", src->slaveId, data[0], len);
+  Serial.print("Response TCP IP: ");
+  Serial.println(srcIp);
+  
+  transRunning = 0;
+  slaveRunning = 0;
+  return Modbus::EX_PASSTHROUGH;
+}
+
+
+void setup() {
+  Serial.begin(115000);
+  WiFi.begin("E2", "*****");
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(1000);
+    Serial.print(".");
+  }
+  Serial.println("");
+  Serial.println("IP address: ");
+  Serial.println(WiFi.localIP());
+    
+  tcp.server(); // Initialize ModbusTCP to pracess as server
+  tcp.onRaw(cbTcpRaw); // Assign raw data processing callback
+  
+  //S.begin(19200, SWSERIAL_8E1);
+  //rtu.begin(&S, DE_RE);  // Specify RE_DE control pin
+  sym.begin((Stream*)&P2);
+  sym.slave(1);
+  sym.addHreg(1, 100);
+  rtu.begin((Stream*)&P1);  // Specify RE_DE control pin
+  rtu.master(); // Initialize ModbusRTU as master
+  rtu.onRaw(cbRtuRaw); // Assign raw data processing callback
+}
+
+void loop() { 
+  sym.task();
+  rtu.task();
+  tcp.task();
+  yield();
+}

examples/README.md

@@ -24,7 +24,7 @@ Examples of using callback functions.
 
 Modbus file operations examples.
 
-## [Modbus RTU to Modbus TCP bridge](bridge)
+## [ModbusRTU to ModbusTCP bridge and related functions](bridge)
 
 Very basic example of accessing ModbusRTU slave device connected to ESP8266/ESP32 via ModbusTCP server.