EtherCAT Arduino Shield by Esmacat (EASE)
Feature Highlights
Raspberry Pi
Codesys
Hardware Connections
Required Libraries
Software
Running the Master Code
Results

Published February 29, 2020 © GPL3+

Raspberry Pi with Codesys PLC UI -Arduino controlling Motors

Use a Raspberry Pi with Codesys to control motors attached to an Arduino Uno using the EtherCAT Arduino Shield by Esmacat (EASE).

IntermediateProtip2 hours4,703

Things used in this project

Hardware components

Raspberry Pi 4 Model B

EtherCAT Master

Arduino UNO

EtherCAT Arduino Shield by Esmacat (EASE)

Ethernet Cable, Cat6a

Power over Ethernet (POE) Injector

DC Adapter

To supply power to the PoE Injector

Adafruit Motor Shield

Servo Motor

(Optional to test the code). Any Servo motor can be used. This specific motor has been used in this tutorial.

DC Motor

(Optional Motor to test the code). Any dc motor can be used. This specific motor has been used in this tutorial.

Stepper Motor

(Optional Motor to test the code). Any stepper motor can be used. This specific motor has been used in this tutorial.

Power Source

Any power source like a lipo battery or battery eliminator to power the motors.

Raspberry Pi Power Supply

Story

You can read more about this and other Esmacat tutorials on the official Esmacat website. Check out our other Hackster.io demos as well.

Detailed documentation of the codes and steps for this tutorial can be found here

Check out our EASE Crowd Supply Campaign Page: https://www.crowdsupply.com/harmonic-bionics/ease

Overview:

In this tutorial, you will learn how to set up a Raspberry Pi with Codesys to act as both a PLC and an EtherCAT master. It will be used to control the motors attached to the EtherCAT Arduino Shield by Esmacat (EASE) Slave device that is attached to an Arduino Uno.

First, some general information about Raspberry Pi and Codesys is discussed.
After learning to set up the Pi and Codesys, you will learn to implement a practical project to control the motors attached to the Arduino Uno and EASE based on user input by updating EASE registers using Codesys.

EtherCAT Arduino Shield by Esmacat (EASE):

EASE is an EtherCAT slave that connects to an EtherCAT master (PC/ Laptop/ Dedicated Master devices like the Esmacat Master S and Esmacat Master C.) It can be stacked on top of Arduino, other MCU boards with an Arduino Uno form factor, and shields. This shield allows high-speed communication with an industry-standard EtherCAT protocol for high-performance robotic applications. Esmacat's simple to use Arduino and Mbed libraries allow for easy coding on the base board and Esmacat's free open source master software has a high-level abstraction so users can run applications within minutes!

1 / 2 • EASE

Feature Highlights:

EASE connects Arduino boards, Arduino-like boards, and Arduino Shields for large-scale applications.
High-speed communication (200Mbps, 200x faster than CAN bus) is supported with EtherCAT which is an industrial-standard fieldbus for automation.
The EtherCAT hardware/software is present only on EASE so there is no performance lost on the MCU baseboard
EASE has the form factor of Arduino Uno, and thus can take advantage of the Arduino ecosystem.
Daisy chain connection between multiple EASE simplifies the topology of wiring.
Power-over-EtherCAT (POE) technology reduces the number of required wires and power outlets.
The data packet between Arduino Board and EASE is communicated via SPI, allowing EASE to be compatible with many different types of boards including Arduino boards and MBed boards.
Arduino and Mbed developed by Esmacat library allow users to easily develop code between the base board and EASE within minutes.
This shield has 8 registers that can be used to send/receive data between devices through the EtherCAT master via Ethernet cables attached to the shield.

More info: https://www.esmacat.com/ease

Suggested Reading: EASE Datasheet.

Raspberry Pi:

Raspberry Pi is a tiny, dual-display, low-cost desktop computer that is used widely in robot brains, smart home hubs, media centers, as a networked AI core and factory controllers. It can also be used as an EtherCAT master just like a Laptop/PC. However, it should be noted that the Pi is a Linux based computer.

Raspberry Pi EtherCAT Master

Codesys:

Codesys

CODESYS is a PLC programming environment that is used widely by many industrial automation companies like Beckhoff, Bosch, Wago, etc. You can program in Codesys using the traditional Ladder Logic or using Structured text and Continuous Flow Chart (IEC 61131-3 standards).

For this tutorial, the following packages must be downloaded from the links below,

Note: You must create a Codesys account in order to download the above files.

Note: The ESI (EtherCAT Slave Information) of EASE must be added to Codesys to use it in the program. Refer to the documentation (section 3.2.2) below to get detailed steps for the initial setup of Codesys for Raspberry Pi.

Hardware Connections:

The primary hardware components include,

EtherCAT slave (EASE with Arduino)
EtherCAT Master (Raspberry Pi)
Power Over Ethernet (POE Injector)
Ethernet cables
Power Source (for Motors)
Motors to test the code
DC Adapter (for POE)

Since EASE uses a POE injector, there is no need to power the Arduino board separately. EASE can power the board andany other boards connected through EtherCAT!

The connections are as shown in the two schematics attached in the "Schematics" section of this tutorial. "The Hardware setup schematic" gives an overview of the connections to be made while the "Physical connection schematic" shows the setup once all the connections are made.

Note: Make sure the Ethernet connections are fit tightly into the sockets. (Loose connections may lead to the slave device not being recognized.)

Required Libraries:

An EASE Library for Arduino to communicate with the Arduino subsystem.

The link to the library has been included under the Code section. Download the library and add it to the Arduino IDE (Sketch-> Include Library-> Add.ZIP library and select the file) to get started with the coding part.

Suggested Reading:Getting started with EASE.

Software :

The software required for this tutorial involves coding for

the Esmacat Master and
the Arduino.

Programming the Esmacat Master:

Open the Codesys software and import the.project file downloaded from the Code section and build the source code.

Suggested Reading: Section 8 Getting Started with EASE & Codesys.

Coding the Arduino:

Open the Arduino IDE and create a new sketch file. The complete code for this tutorial is available under the Code section named "EASE_codesys_motor_control".

Compile and Upload this code into the Arduino board connected with EASE.

Note: Make sure you check whether the Board and Port are chosen correctly in the IDE.

Running the Master Code:

When running the master code you get a result similar to the following on the Codesys environment (with a graphical UI showing the update of registers in EASE).

Master Code Execution

Results:

By now you have successfully programmed the Arduino boards and the Esmacat master! The visualization tool in Codesys gives a graphical UI to control the on-board LED in Arduino similar to the GIF attachment at the start of the tutorial and the YouTube video below.

Video Demo

Final Notes: A detailed step by step tutorial for this project can be found in the document attached below.

Suggested Reading: EASE & Codesys Motor Control.

Code

/*
  Motors Control

  This sketch does the following:
  1) Controls 3 different motors attached to the Motor Shield.
  2) Depending on the motor selected as input form the Master,
      2.1) If the motor selected is a Servo Motor, the motor is set at the desired position.
      2.2) If the motor selected is a DC Motor, the motor is set to run at a particular speed 
           by modifying the pwm control input to the motor.
      2.3) If the motor is selected is a Stepper Motor, the motor is set to run at a particular
           speed.        
           
  created 4 Feb 2020
  by Harmonic Binonics Inc. (https://www.harmonicbionics.com/). 
  
*/

#include <Wire.h>
#include <Adafruit_MotorShield.h>   // Include the Adafruit Motor Shield Library

#include <Servo.h>   // Include the Arduino Servo Library
#include <Esmacatshield.h>      //Include the Esmacat Arduino Library

// Define the Pin Numbers as Macros
# define servo_control_pin 9   // Servo is connected to Servo port #1 on the Motor Shield
# define ARDUINO_UNO_SLAVE_SELECT 10      // The chip selector pin used in Arduino Uno is 10 

// Create objects for various motor classes and EASE
Esmacatshield ease_with_motor(ARDUINO_UNO_SLAVE_SELECT);      // Create a slave object and specify the Chip Selector Pin

Adafruit_MotorShield AFMS = Adafruit_MotorShield();   // Create the motor shield object with the default I2C address

// Create an object for Stepper Motor
Adafruit_StepperMotor *stepper_motor = AFMS.getStepper(200, 2);   // Connect a stepper motor with 200 steps per revolution (1.8 degree)
                                                                  // to motor port #2 (M3 and M4)
// Create an object for DC Motor
Adafruit_DCMotor *dc_motor = AFMS.getMotor(2);   // Connect a DC motor to motor port #1 (M2)

Servo servo_2;  // Create an object for the Servo Motor Class 
                // Servo is connected to Servo port #2 on the Motor Shield so the name servo_2 is used

// Required variables Initialization

int operation_state = 0;   // Variable to choose which motor to control
int servo_angle = 0;   // Variable to store the input angle
int stepper_speed = 0;   // Variable to store stepper motor speed
int dc_speed = 0;   // Variable to store dc motor speed
int ease_registers[8];      // EASE 8 registers

void setup() 
{
  AFMS.begin();  // create with the default frequency 1.6KHz
  
  stepper_motor->setSpeed(10);  // 10 rpm random initialization of speed
  
  dc_motor->setSpeed(0);   // Set the initial Speed of DC Motor to 0 

  servo_2.attach(servo_control_pin);   // Servo 1 on Adafruit Motor Shield is connected
                                       // to Pin 10 of the Arduino board
  ease_with_motor.start_spi();      // Start SPI for EASE
}

void loop() 
{
  
  ease_with_motor.get_ecat_registers(ease_registers);   // Update all the EASE registers with new values

  operation_state = ease_registers[0];   // Motor to control
  servo_angle = ease_registers[1];   // Actual Servo position
  dc_speed = ease_registers[2];   // Actual dc motor speed
  stepper_speed = ease_registers[3];   // Actual Stepper Motor Speed

  if(operation_state)   // Operate motors only if main switch is ON
  {
    servo_2.write(servo_angle);
    if(dc_speed > 0)
    {
      dc_motor->setSpeed(dc_speed);
      dc_motor->run(FORWARD);
    }
    else
    {
      dc_motor->setSpeed(dc_speed);
      dc_motor->run(BACKWARD);
    }
    if(stepper_speed > 0)
    {
      stepper_motor->step(stepper_speed,FORWARD,SINGLE);
    }

    else
    {
      stepper_motor->step(stepper_speed,BACKWARD,SINGLE);
    }
  }
  
  else
  {
    dc_speed = 0;
    stepper_speed = 0;
    servo_angle = 0;
  }
}

Credits

Esmacat

11 projects • 15 followers

Esmacat is an easy yet powerful EtherCAT solution for robotics. Our EtherCAT tech allow users to run EtherCAT applications in minutes!

Raspberry Pi with Codesys PLC UI -Arduino controlling Motors