I am having modbus device . i would like to read data from modbus device through nodemcu and display data.
I have made connection as shown image attached. I have made connection as shown in example
http://en.trialcommand.com/blog/esp8266-master-modbus-rtu-rs232/instead of using usb to rs232 i used usb to ttl out,
with modbus connected with usb to ttl. if i send request from modscan32 i used to get response from modbus device.
i would like to know few thing from above example
- How to view nodemcu modbus register using modscansoftware, if i select nodemcu comport it gives out time out error.
- HOW can i read data from my slave device using this library.
- I tried other library function its not working as soon as connect TX and rx line with other library it stop working
my application is simple node mcu must send request like modscan32 from usbto ttl .read reply and display output.
i have attached serial out for reference. weather RS232 circuit is needed???
Nodemcu test code.
#include <ModbusMaster232.h>
#include <SoftwareSerial.h> // Modbus RTU pins D7(13),D8(15) RX,TX
// Instantiate ModbusMaster object as slave ID 1
ModbusMaster232 node(1);
void setup()
{
Serial.begin(9600);
delay(100);
node.begin(9600); // Modbus RTU
delay(100);
Serial.println("Connected ");
Serial.println("Modbus RTU Master Online");
}
void loop()
{
//Website http://trialcommand.com
///////// Holding Register [0] A [9] = 10 Holding Registers Escritura
///////// Holding Register [0] A [9] = 10 Holding Registers Writing
int Mdelay = 5;
node.readHoldingRegisters(0, 1);
Serial.print("[0] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(1, 1);
Serial.print(" [1] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(2, 1);
Serial.print(" [2] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(3, 1);
Serial.print(" [3] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(4, 1);
Serial.print(" [4] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(5, 1);
Serial.print(" [5] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(6, 1);
Serial.print(" [6] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(7, 1);
Serial.print(" [7] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(8, 1);
Serial.print(" [8] ");
Serial.print(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
node.readHoldingRegisters(9, 1);
Serial.print(" [9] ");
Serial.println(node.getResponseBuffer(0));
node.clearResponseBuffer();
delay(Mdelay);
///////// Holding Register [10] A [19] = 10 Holding Registers Lectura
///// Holding Register [10] A [19] = 10 Holding Registers Reading
node.writeSingleRegister(10, random(1, 10 ));
node.writeSingleRegister(11, random(1, 10 ));
node.writeSingleRegister(12, random(1, 10 ));
node.writeSingleRegister(13, random(1, 10 ));
node.writeSingleRegister(14, random(1, 10 ));
node.writeSingleRegister(15, random(1, 10 ));
node.writeSingleRegister(16, random(1, 10 ));
node.writeSingleRegister(17, random(1, 1000 ));
node.writeSingleRegister(18, random(1, 10 ));
node.writeSingleRegister(19, random(1, 1000 ));
}
I could not able to replicate the example to test it out. It work till serial print not work with modscan32 software
