First basic version

Working single device code

.gitignore

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+my_settings.h

Blynk-PZEM-004T-v3.0-Multiple-device.ino

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+/*
+   Blynk PZEM 004T v3.0 Multiple Device Connection Program 
+
+   Source: https://github.com/pkarun/Blynk-PZEM-004T-v3.0-Multiple-device
+   https://github.com/pkarun/Blynk-PZEM-004T-v3.0
+   
+   Reference: https://community.blynk.cc/t/pzem-004t-v3-0-and-nodemcu-wemos-mini-running-on-blynk-how-to-procedure/39338
+
+   Wiring:
+   
+   PZEM 004T v3.0 to NodeMCU
+   5v to vin
+   RX to D6
+   TX to D5
+   GND to GND
+   
+   
+*/
+
+//#include "settings.h" //Make sure you UNCOMMENT this before you use. 
+#include "my_settings.h" //This is my personal settings. You can remove this line or comment-out when you are using.
+
+#include <ArduinoOTA.h>
+#include <BlynkSimpleEsp8266.h>
+#include <SimpleTimer.h>
+#include <ModbusMaster.h>
+#include <ESP8266WiFi.h>
+
+
+#include <SoftwareSerial.h>  //  ( NODEMCU ESP8266 )
+SoftwareSerial pzem(D5, D6); // (RX,TX) connect to TX,RX of PZEM for NodeMCU  
+//SoftwareSerial pzem(D7,D8);  // (RX,TX) connect to TX,RX of PZEM
+#include <ModbusMaster.h>
+ModbusMaster node;
+
+BlynkTimer timer;
+
+double voltage_usage, current_usage, active_power, active_energy, frequency, power_factor, over_power_alarm; 
+
+uint8_t result;  uint16_t data[6];
+
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println("Start serial");
+  pzem.begin(9600);
+  Serial.println("Start PZEM serial");
+  node.begin(1, pzem);
+  Serial.println("Start PZEM"); // 1 = ID MODBUS
+
+#if defined(USE_LOCAL_SERVER) 
+  Blynk.begin(AUTH, WIFI_SSID, WIFI_PASS, SERVER, PORT);
+#else
+  Blynk.begin(AUTH, WIFI_SSID, WIFI_PASS);
+#endif
+  ArduinoOTA.setHostname(OTA_HOSTNAME);
+  ArduinoOTA.begin();
+
+
+timer.setInterval(10000L, sendtoBlynk); // send values blynk server every 10 sec
+
+
+}
+
+void sendtoBlynk() {
+  Blynk.virtualWrite(vPIN_VOLTAGE,               voltage_usage);
+  Blynk.virtualWrite(vPIN_CURRENT_USAGE,         current_usage);
+  Blynk.virtualWrite(vPIN_ACTIVE_POWER,          active_power);
+  Blynk.virtualWrite(vPIN_ACTIVE_ENERGY,         active_energy);
+  Blynk.virtualWrite(vPIN_FREQUENCY,             frequency);
+  Blynk.virtualWrite(vPIN_POWER_FACTOR,          power_factor);
+  Blynk.virtualWrite(vPIN_OVER_POWER_ALARM,      over_power_alarm);
+}
+
+
+void pzemdata(){
+
+    result = node.readInputRegisters(0x0000, 10);
+
+    if (result == node.ku8MBSuccess)  
+    {
+    voltage_usage      = (node.getResponseBuffer(0x00) / 10.0f);
+    current_usage      = (node.getResponseBuffer(0x01) / 1000.000f);
+    active_power       = (node.getResponseBuffer(0x03) / 10.0f);
+    active_energy      = (node.getResponseBuffer(0x05) / 1000.0f);
+    frequency          = (node.getResponseBuffer(0x07) / 10.0f);
+    power_factor       = (node.getResponseBuffer(0x08) / 100.0f);
+    over_power_alarm   = (node.getResponseBuffer(0x09));
+    }
+
+  Serial.print("VOLTAGE:           ");   Serial.println(voltage_usage);   // V
+  Serial.print("CURRENT_USAGE:     ");   Serial.println(current_usage, 3);  //  A
+  Serial.print("ACTIVE_POWER:      ");   Serial.println(active_power);   //  W
+  Serial.print("ACTIVE_ENERGY:     ");   Serial.println(active_energy, 3);  // kWh
+  Serial.print("FREQUENCY:         ");   Serial.println(frequency);    // Hz
+  Serial.print("POWER_FACTOR:      ");   Serial.println(power_factor);
+  Serial.print("OVER_POWER_ALARM:  ");   Serial.println(over_power_alarm, 0);
+  Serial.println("====================================================");
+}
+
+void loop() {
+  Blynk.run();
+  ArduinoOTA.handle();
+  timer.run();
+  pzemdata();
+
+  delay(1000);
+}

settings.h

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+                           /////////////////////////////////////////////////////////////////
+                          //                           Settings                          //
+                         /////////////////////////////////////////////////////////////////
+
+
+
+/***************************************************
+ *        Blynk Virtual Pin Assignment
+ **************************************************/
+
+#define vPIN_VOLTAGE                V0
+#define vPIN_CURRENT_USAGE          V1
+#define vPIN_ACTIVE_POWER           V2
+#define vPIN_ACTIVE_ENERGY          V3
+#define vPIN_FREQUENCY              V4
+#define vPIN_POWER_FACTOR           V5
+#define vPIN_OVER_POWER_ALARM       V6
+
+
+/***************************************************
+ *       Blynk Settings 
+ **************************************************/
+
+#define AUTH "Your Blynk Auth Token" //You should get Auth Token in the Blynk App. 
+
+
+/***************************************************
+ *        WiFi Settings
+ **************************************************/
+
+#define WIFI_SSID "Your WiFi Network Name"
+#define WIFI_PASS "Your Wifi Password"
+
+/***************************************************
+ *        Server Settings
+ **************************************************/
+
+#define OTA_HOSTNAME "PZEM-004v3"
+
+
+// Remove/comment-out below 2 lines when use Blynk hosted server
+
+#define USE_LOCAL_SERVER       //Use local Blynk Server - comment-out if use Blynk hosted cloud service
+#define SERVER "xxx.xxx.xx.xxx" //comment-out if use Blynk hosted cloud service
+
+#define PORT 8080