MODBUS TCP via WiFi Shield

[Franklin97355]

Perhaps if you posted your code and a link to the library we could look for options.

[skyscan]

Could you post the complete library?

[Franklin97355]

lloyd the link is two posts above yours. https://code.google.com/p/mudbus/downloads/list.

[skyscan]

I was hoping to get the modified modbus library for the WiFi shield CC3000.

I was unclear on ductsoup's edit in last post

[frank_dunn1]

I have modified this library to work on a ESP8266 with arduino 1.6.1p , It works but I get no response every second modbus frame . Would anybody be interested to
take a look at my code .

[frank_dunn1]

The ESP8266 is not connected to ATmega328P . I am using Arduino 1.6.1-p1 to program ESP8266 directly .

Code: Select all

/*

 Simple Test
 
 */

//
// Note: The Arduino IDE does not respect conditional included
// header files in the main sketch so you have to select your
// hardware here, and in ModbusTCP.h.
//
// If you want to use both wired and wireless in different 
// projects copy ModbusTCP.h and ModbusTCP.cpp to the individual
// sketch folders instead of installing the library.
//

//#include <Ethernet.h>
//#include <Adafruit_CC3000.h>
#include<ESP8266WiFi.h>
//#include <SPI.h>
#include "ModbusTCP.h"

// Register map for this example
#define S1_FloatConstant 40001 // modpoll -m tcp -t 4:float -r 40001 [ip_addr] 
#define S1_CurrentMillis 40003 // modpoll -m tcp -t 4:int -r 40003 [ip_addr]
#define S1_FeetPerMile   40005 // modpoll -m tcp -t 4 -r 40005 [ip_addr]

ModbusTCP m;

const char* myssid     = "SSID";
const char* mypassword = "password";

void setup(void)
{
  Serial.begin(115200);
  
  // set some initial values
  //m.setFloat(S1_FloatConstant, PI);
  //m.setU32(S1_CurrentMillis, millis());
  //m.setU16(S1_FeetPerMile, 5280);
  
  //uint8_t mac[]     = { 0x70, 0xFF, 0x76, 0x00, 0xDF, 0x25 };
  //m.begin(mac);
  m.begin(myssid,mypassword);
}

void loop(void)
{
  // Process MODBUS requests on every scan
  m.run();
  //Serial.println(WiFi.localIP());
  delay(40);
  // Update the MODBUS registers  
  //m.setU32(S1_CurrentMillis, millis());
}

[sree741]

Hi frank, your motive was appreciating.are you done the modbus tcp wifi slave using arduino and ESP8266.Iam trying it for past 10 days.still not succeeded.If you have the currect code please explain

[crazyharold]

I modified the modbusTCP library for ESP8266 use.
Currently it works, but the connection drops after each request.
I think it has to do with the use of "WiFiClient clientrequest = mb_server.available();"

Can someone have a look at it ?
Just unzip the file and open in Arduino 1.6.5

Regards, Harold.

I added a second zipfile,
The first one creates a ESP8266 access point.
The second one connects to the specified SSID/Password.

[frank_dunn1]

Hi Harold

I had the same behaviour from the code I posted a while ago , sorry I dont know where to start looking .

[ibbba]

Hello,I just finished a working Modbus TCP library that works with standard Arduino Ethernet shield,Sparkfun Thing (Esp8266 based board) and should work with Adafruit CC3000 Wifi shield.
I don't have the Adafruit shield,so if somebody can give it a try and report will be very useful.
The used board must me defined in the supplied header file.

ModbusTCPSlave.zip

(12.28 KiB) Downloaded 2182 times

[frank_dunn1]

hi ibbba

I tested your library on a olimex esp8266 board , it seems to work fine. With a 200msec poll delay it runs, with a 100msec delay i get reboots .
The olimex board have gpio5 connected to a relay , how can I change this without changing the header file ?

[ibbba]

I personally use to poll not less than one second,so I take your test like a speed test... Ok good.... Regarding The output led that I use to monitor can be ridefined in the header file,or you can delete every call to digitalWrite in The cpp file... Up to you... I hope somebody can test it with The Adafruit shield

[frank_dunn1]

Hi ibbba

I notice when I test your library with modbusmaster that stays connected , the code in the main loop never executes until I disconnect the modbusmaster .

[ibbba]

Hi ibbba

I notice when I test your library with modbusmaster that stays connected , the code in the main loop never executes until I disconnect the modbusmaster .

Yes this is an issue due to the Wifi library...if you check with the standard ethernet shield you will notice that the loop is excuted normally...to avoid this you have to close the connection after each request...I use a Rasperry PI to poll with minimalmodbus python library and closing the connection after each request do the job.

[frank_dunn1]

hi ibbba

I tested the code using the Ticker library to call functions in the main loop and this works fine while the client stays connected .