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11 years, 10 months ago.

ModBus RS485 Mbed library

Hello all,

I wonder if there is any MODBUS / RS485 Mbed library available? Can this be used to interface mbed ith Schneider energy meters..

Thanks!

Not posting an answer because the question is so old, but there is a port of FreeModBus available now and there are two other RTU implementations.

RS485 transmit control may give some problems though. Standard MBED libs don't make it easy to detect end of sending.

posted by Oliver Broad 21 Mar 2016

2 Answers

Abhinav Jadon
10 years, 4 months ago.

Try modserial

Gourav Kumar
5 years, 11 months ago.

I am using this code, but not getting any data. I am using STM32F4 and MAX485

    #include "mbed.h"
   #include <RS485.h>

    Serial pc(PC_6, PC_7); 

  RS485 RS485(PA_2,PA_3, PC_3); // Tx, Rx , !RE and DE MAX485 pin
  
   DigitalOut ho(PC_3); // this pin should be connected to !RE and DE
   typedef uint8_t byte;
 
  byte regvalue[9];
  byte data[9] = {0x0B,0x04,0x00,0x48,0x00,0x02,0xf1,0xdd};//your data
   int main()
   {
     RS485.baud(9600);
     pc.baud(9600);
     pc.printf("main\r\n");
     while(1) {
        pc.printf("Starting\r\n");
        ho = 1;                  // Enable sending on MAX485
    //    RS485.sendMsg(data,sizeof(data));
        wait_ms(600);            // Must wait for all the data to be sent   
        ho = 0;                  // Enable receiving on MAX485
        pc.printf("Getting data\r\n");
        pc.printf(RS485.readable() >0 ? "Yes" : "Not readable \r\n");
        
        if(RS485.readable() >0){
            memset(regvalue,0,sizeof(regvalue));
            wait_ms(200);
            RS485.recvMsg(regvalue,sizeof(data),500);
            wait_ms(200);
            for (int count = 0; count < 9; count++) {
                pc.printf("%X - ", regvalue[count]);
            }
        }else printf("No Data\r\n");
        printf("Done\r\n");
        printf("  \r\n");
        wait_ms(1000);
     }
     }