Hi friend,
I 'm a Greek student and my diploma project refers to arduino Omron MX2 VFD control system.
I have an arduino mega, an MX2 Omron motor inverter, an RS485 to arduino shield and i like to control this MX2 inverter with arduino via RS485 cable and modbus rtu protocol.
I need help me with code to do it for my diploma exercise. As long as i try with different modbus arduino libraries, i didn't make it.
I need to have a simple control an VFD Omron MX2 inverter through arduino.
The protocol i will use is a Modbus RTU through RS485 serial connection.
I 've managed to control this inverter from arduino serial port through software modbus poll by giving commands from the test function inside program Modbus Poll like "01 05 00 00 FF 00" and the inverter goes to RUN mode, but i couldn't do it the same from arduino as a master.
The code i've found about MX2 VFD from another person is the above:
/**
* Modbus master example 1:
* The purpose of this example is to query an array of data
* from an external Modbus slave device.
* The link media can be USB or RS232.
*
* Recommended Modbus slave:
* diagslave http://www.modbusdriver.com/diagslave.html
*
* In a Linux box, run
* "./diagslave /dev/ttyUSB0 -b 19200 -d 8 -s 1 -p none -m rtu -a 1"
* This is:
* serial port /dev/ttyUSB0 at 19200 baud 8N1
* RTU mode and address @1
*/
#include <ModbusRtu.h>
// data array for modbus network sharing
uint16_t au16data[16];
uint8_t u8state;
/**
* Modbus object declaration
* u8id : node id = 0 for master, = 1..247 for slave
* u8serno : serial port (use 0 for Serial)
* u8txenpin : 0 for RS-232 and USB-FTDI
* or any pin number > 1 for RS-485
*/
Modbus master(0,0,9); // this is master and RS-232 or USB-FTDI, PIN 9 PARA INDICAR QUE TRASMITO
/**
* This is an structe which contains a query to an slave device
*/
modbus_t telegram;
unsigned long u32wait;
void setup() {
master.begin( 9600 ); // baud-rate at 19200
master.setTimeOut( 2000 ); // if there is no answer in 2000 ms, roll over
u32wait = millis() + 1000;
u8state = 0;
}
void loop() {
switch( u8state ) {
case 0:
if (millis() > u32wait) u8state++; // wait state
break;
case 1:
telegram.u8id = 1; // slave address
telegram.u8fct = 5; // function code (this one is registers read)
telegram.u16RegAdd = 0; // start address in slave
telegram.u16CoilsNo = 2; // number of elements (coils or registers) to read
//telegram.au16reg = au16data; // pointer to a memory array in the Arduino
// PARA EL VARIADOR OMRON MX1: MODBUS RTU 01 05 00 00 FF 00 -> START
// 01 -> SLAVE (VFD OMRON)
// 05 -> WRITE COIL
// 00 00 -> ADDRESS COIL
// FF 00 -> VALUES TO WRITE IN COIL FOR RUN
telegram.au16reg[0] = 0;
telegram.au16reg[1] = 0;
telegram.au16reg[2] = 0;
telegram.au16reg[3] = 0;
telegram.au16reg[4] = 0;
telegram.au16reg[5] = 0;
telegram.au16reg[6] = 0;
telegram.au16reg[7] = 0;
telegram.au16reg[8] = 1;
telegram.au16reg[9] = 1;
telegram.au16reg[10] = 1;
telegram.au16reg[11] = 1;
telegram.au16reg[12] = 1;
telegram.au16reg[13] = 1;
telegram.au16reg[14] = 1;
telegram.au16reg[15] = 1;
master.query( telegram ); // send query (only once)
delay(3500);
telegram.u8id = 1; // slave address
telegram.u8fct = 6; // function code (this one is registers read)
telegram.u16RegAdd = 1; // start address in slave
telegram.u16CoilsNo = 4; // number of elements (coils or registers) to read
//telegram.au16reg = au16data; // pointer to a memory array in the Arduino
//telegram.au16reg = 0000000111110100;
// PARA EL VARIADOR OMRON MX1: MODBUS RTU 01 06 00 01 01 F4 -> CHANGE FQ
// 01 -> SLAVE (VFD OMRON)
// 06 -> WRITE IN REGISTE
// 00 01 -> REGISTER ADDRESS
// 01 F4 -> VALUE TO WRITE IN THE REGISTER TO CHANGE THE MOTOR FREQUENCY
telegram.au16reg[0] = 0;
telegram.au16reg[1] = 0;
telegram.au16reg[2] = 0;
telegram.au16reg[3] = 0;
telegram.au16reg[4] = 0;
telegram.au16reg[5] = 0;
telegram.au16reg[6] = 0;
telegram.au16reg[7] = 1;
telegram.au16reg[8] = 1;
telegram.au16reg[9] = 1;
telegram.au16reg[10] = 1;
telegram.au16reg[11] = 1;
telegram.au16reg[12] = 0;
telegram.au16reg[13] = 1;
telegram.au16reg[14] = 0;
telegram.au16reg[15] = 0;
master.query( telegram ); // send query (only once)
delay(3500);
telegram.u8id = 1; // slave address
telegram.u8fct = 5; // function code (this one is registers read)
telegram.u16RegAdd = 1; // start address in slave
telegram.u16CoilsNo = 2; // number of elements (coils or registers) to read
//telegram.au16reg = au16data; // pointer to a memory array in the Arduino
// PARA EL VARIADOR OMRON MX1: MODBUS RTU 01 05 00 00 00 00 -> STOP
// 01 -> ESCLAVO (VARIADOR OMRON)
// 05 -> ESCRIBIR EN UNA BOBINA
// 00 00 -> DIRECCION DE LA BOBINA
// 00 00 -> VALOR A ESCRIBIR EN LA BOBINA PARA STOP
telegram.au16reg[0] = 0;
telegram.au16reg[1] = 0;
telegram.au16reg[2] = 0;
telegram.au16reg[3] = 0;
telegram.au16reg[4] = 0;
telegram.au16reg[5] = 0;
telegram.au16reg[6] = 0;
telegram.au16reg[7] = 0;
telegram.au16reg[8] = 0;
telegram.au16reg[9] = 0;
telegram.au16reg[10] = 0;
telegram.au16reg[11] = 0;
telegram.au16reg[12] = 0;
telegram.au16reg[13] = 0;
telegram.au16reg[14] = 0;
telegram.au16reg[15] = 0;
master.query( telegram ); // send query (only once)
delay(3500);
u8state++;
break;
case 2:
master.poll(); // check incoming messages
if (master.getState() == COM_IDLE) {
u8state = 0;
u32wait = millis() + 100;
}
break;
}
}
All i want is to help me build an arduino code to give simple commands to inverter like Start, Stop, change frequency, reverse etc.
Also it would be nice if i can show somehow some values from the inverter to an LCD screen but i will do it later.
This is the manual in PDF for Omron MX2 inverter modbus protocol.
MX2 Modbus PDF
TIA