Communication in Modbus RTU

Robotiq_Customer 2016-04-29

Hi,

I want to communicate in Modbus RTU with the Robotiq FT300, but I can't.
I am using a RS232 to RS485 adapter as I know your sensor communicates in RS485.

Any ideas why it doesn't work?

Thanks

Catherine_Bernier 2016-04-29

Hey there.

Are you using the Robotiq tested adapter?

If not, this might be the problem as the pinout might not be correct.
Make sure to refer to this image:

The simplest way to proceed would be to contact our application engineer and get the Robotiq tested adapter for this application.
For more info on the wiring, you can get access to the support manual here.

Robotiq_Customer 2016-04-29

Well thanks!

This was the problem... My converter wasn't setup properly.

Thanks for your support!

jainaayush2006 2019-02-14

Hey there,

I'm also trying to do the same thing, trying to communicate with FT300 with Arduino using RS485 to RS232 adapter and then using RS232 to TTL converter. I not good at coding, so please can someone help me with the code to read the values on Arduino.

bcastets 2019-02-14

Hello Aayush Jain,

The following arduino library looks like a reference for Modbus communication:
https://github.com/4-20ma/ModbusMaster

I found some interesting video about how to communicate in Modbus RTU with ardiuno. I recommand you check that:
https://www.youtube.com/watch?v=HPZrGuBtk_c
https://www.youtube.com/watch?v=tBw15SfmuwI

I did not tested but based on those videos, I would make a program like the following to display force and torque on Ardiuno console on PC side:

#include <ModbusMaster.h>

#define MAX485_DE 3
#define MAX485_RE_NEG 2

ModbusMaster node;

void preTransmission()
{

digitalWrite(MAX485_RE_NEG,1);

digitalWrite(MAX485_DE,1);

}

void postTransmission()
{

digitalWrite(MAX485_RE_NEG,0);

digitalWrite(MAX485_DE,0);

}

void setup()
{

pinMode(MAX485_RE_NEG, OUTPUT);

pinMode(MAX485_DE,OUTPUT);

//Init in receive mode

digitalWrite(MAX485_RE_NEG,0);

digitalWrite(MAX485_DE,0);

//Modbus communication runs at 19200 baud (according to FT300 manual 4.4.1 ModbusRTU)

Serial.begin(19200);

//Modbus slave ID 9 (according to FT300 manual 4.4.1 ModbusRTU)

node.begin(9,Serial);

//Callbacks allow us to configure the RS485 transceiver correctly

node.preTransmission(preTransmission);

node.postTransmission(postTransmission);

}

void loop()
{

uint8_t resutlMain;

//Read registers where is written force and torque value (according to FT300 manual 4.4.1 ModbusRTU)

//Register : Description

//180: Fx

//181: Fy

//182: Fz

//183: Mx

//184: My

//185: Mz

//Read 6 registers starting from address 180

resultMain=node.readInputRegisters(180,6);

if (resultMain == node.ku8MBSuccess)

{

Serial.println("----------------");

Serial.println("Fx: ");

Serial.println(node.getResponseBuffe(0x00 / 100.0f);

Serial.println("Fy: ");

Serial.println(node.getResponseBuffe(0x01 / 100.0f);

Serial.println("Fz: ");

Serial.println(node.getResponseBuffe(0x02 / 100.0f);

Serial.println("Mx: ");

Serial.println(node.getResponseBuffe(0x03 / 100.0f);

Serial.println("My: ");

Serial.println(node.getResponseBuffe(0x04 / 100.0f);

Serial.println("Mz: ");

Serial.println(node.getResponseBuffe(0x05 / 100.0f);

}

syed 2020-10-11

Hello there,

I am using FT300 force torque sensor.
I am trying to communicate with sensor from C++ (to read values of forces and torques), however, i am not good at coding. Can anyone help in providing code to read data in C++ (visual studio)

Thanks in advance

bcastets 2020-10-12

We provide on our support page a C package to communication with the ft300. It would be a good material to start.

https://assets.robotiq.com/website-assets/support_documents/document/FT-300_dev_package_SDP-1.0.1_20180328.rar

You can find more details about modbus communication in ft300 manual.

syed 2020-10-18

bcastets said:

We provide on our support page a C package to communication with the ft300. It would be a good material to start.

https://assets.robotiq.com/website-assets/support_documents/document/FT-300_dev_package_SDP-1.0.1_20180328.rar

You can find more details about modbus communication in ft300 manual.

I checked all the details in manual and used the code you provided for Arduino , the code works by making a few minor changes. However, register [resultMain=node.readInputRegisters(180,6)] 01, 03, and 04 are giving values 655 , 65 and 65, the rest seems fine.

Can you kindly guide over this?

regards
syed