View source for OpenPLC-with-LDmicro/C3/A-to-D-Converter-Read-Instruction/English



{| border="1"
|-

| align=center| '''Visual Cue'''
| align=center| '''Narration'''
|-
|| Slide 1: 
|| Welcome to the spoken tutorial on '''A to D Converter Read '''
|-
|| Slide 2: Learning Objectives
* A to D Converter read instruction

|| In this tutorial we’ll learn about the working of 
* '''A to D '''i.e.''' Analog to Digital Converter Read''' instruction

|-
|| Slide 3: System Requirements
* Ubuntu 18.04''' '''OS
* LDmicro
* OpenPLC Mainboard
* 24V, 2A SMPS
* USBasp programmer
* Heater module

|| To record this tutorial I am using:
* '''Ubuntu Linux 18.04''' operating system
* '''LDmicro'''
* '''OpenPLC Mainboard'''
* '''24V, 2A SMPS'''
* '''USBasp programmer'''
* '''Heater module'''
|-
|| Slide 4: Pre-requisites
* Heater module 
* '''Compare''' instructions

If not, please refer to the relevant tutorials from [https://spoken-tutorial.org/ Home | spoken-tutorial.org]
|| 
* To follow this tutorial, you should be familiar with 
** '''Heater module''' and
** '''Compare''' instructions.

* If not, please refer to the relevant tutorials in this series on this website.

|-
|| Slide 5: Prerequisites - Hardware setup

hardware-prerequisite.jpg
|| Connect''' SMPS''' and '''USBasp''' to the '''Mainboard''' as shown in the picture.

Keep these connections throughout this tutorial.
|-
|| Slide 6: A/D Converter Read
* Reads the data collected by ADC built within a microcontroller
* Can be manipulated with general variable operations 
* ADC of ATmega16 is of 10-bit resolution i.e. it outputs value from 0 to 1023

|| This instruction reads the '''data''' collected by '''ADC''' built within a '''microcontroller'''.

The '''data''' collected will be stored in a '''variable'''.

This '''ADC variable''' can be manipulated using '''Compare''' and '''Arithmetic''' operations.

The '''ADC''' of '''ATmega16''' is of '''10-bit resolution''' i.e. it outputs values from 0 to 1023.
|-
|| 
|| We will learn about the working of this instruction using a simple '''analog''' example.
|-
|| Slide: Example
* Control the temperature of the resistor of the OpenPLC Heater module

'''Conditions:'''
* If ADC value < 800, 
Output: fan is ON and heat is OFF* If ADC value > 900, 

Output: fan is OFF and heat is ON
|| In this tutorial we will control the temperature of the '''resistor'''.

That is, the heating element of the '''OpenPLC Heater module'''.

We will have the '''conditions''' as follows.

If the '''ADC''' value is less than 800, turn '''on''' the fan and turn '''off''' the heating element.

If the '''ADC''' value is greater than 900, turn '''off''' the fan and turn '''on''' the heating element.

You can set the limit values according to your requirements.
|-
|| 
|| Recall that the '''temperature sensor''' used in the '''Heater module''' is a '''NTC thermistor'''.

Thus, the '''resistance''' of the '''thermistor''' is inversely proportional to the temperature.
|-
|| Open the LDmicro from the launcher bar
|| Let us open '''LDmicro'''.
|-
|| Click Instructions -> Analog Operations -> Insert A/D converter read
|| Insert a '''A/D converter read''' instruction as shown.
|-
|| Double click on Read ADC >> Type ‘temp’ in the destination column >> Click OK button
|| Double-click on '''Read ADC'''.

We can see a box to enter the destination '''variable'''.

Type '''‘temp’''' and click the '''OK''' button.
|-
|| Highlight Atemp in I/O list
|| We can see that the name '''‘temp’''' is prefixed by '''A'''.

In the''' I/O''' list we can see its '''type''' as ‘'''adc input’'''.
|-
|| Click Edit -> Insert rung after
|| Now insert a '''rung''' below.
|-
|| Place the cursor in the new rung >> Click on Instructions -> Comparison Operators -> Insert GRT
|| Insert a '''greater than compare''' instruction in the new '''rung''' as shown.
|-
|| Double-click on GRT >> Type ‘Atemp’ in the first column >> Type 900 in the second column
|| Double click on it.

Set the '''variable''' to '''Atemp''' and compare it to 900.

Click the '''OK''' button.
|-
|| Place cursor to the right of GRT >> Click on Instructions -> Insert Coil
|| To the right of it, insert a '''Coil'''.
|-
|| Double-click on Ynew >> Type ‘heat’ in the name box >> Select ‘SET-only’ in type >> Click OK button
|| Rename the '''Coil''' as '''‘heat’''' and configure it as '''SET-only Coil'''.
|-
|| Place the cursor parallel to Yheat >> Click on Instructions -> Insert Coil
|| Now, parallel to '''Yheat''' insert another '''Coil'''.
|-
|| Double-click on Ynew >> Type ‘fan’ in the name box >> Select ‘RESET-only’ in type >> Click OK button
|| Rename it as '''‘fan’''' and configure it as '''RESET-only Coil'''.
|-
|| Click Edit -> Insert rung after
|| Insert one more '''rung''' below.
|-
|| Place the cursor in the new rung >> Click on Instructions -> Comparison Operators -> Insert LES
|| Place a '''less than compare''' instruction in the new '''rung''' as shown.

|-
|| Double-click on LES >> Type ‘Atemp’ in the first column >> Type 900 in the second column
|| Double click on it.

Set the '''variable''' as '''Atemp''' and compare it to 800.

Click the '''OK''' button.
|-
|| Place cursor to the right of GRT >> Click on Instructions -> Insert Coil
|| To the right of it insert a '''Coil'''.
|-
|| Double-click on Ynew >> Type ‘heat’ in the name box >> Select ‘RESET-only’ in type >> Click OK button
|| Rename the '''Coil''' as '''‘heat’''' and configure it as '''RESET-only Coil'''.
|-
|| Place the cursor parallel to Yheat >> Click on Instructions -> Insert Coil
|| Now, parallel to '''Yheat''' insert another '''Coil'''.
|-
|| Double-click on Ynew >> Type ‘fan’ in the name box >> Select SET-only’ in type >> Click OK button
|| Rename it as '''‘fan’''' and configure it as '''SET-only Coil'''.
|-
|| 
|| We will now check the working of this '''logic'''.
|-
|| Click Simulate -> Simulation mode >>

Click Simulate -> Real-time simulation
|| Let us turn '''on''' the '''simulation mode'''.

For that, click '''Simulate''' and then on '''Simulation mode.'''

Next, start '''real-time simulation''' as shown.
|-
|| Highlight the state of Yheat, Yfan and Atemp in the I/O list
|| We can observe initially the value of '''Atemp''' is 0 i.e less than 800.

So the state of '''Yheat''' is 0 and '''Yfan''' is 1.
|-
|| Double click on Atemp in the I/O list
|| Double-click on '''Atemp''' in the '''I/O''' list.
|-
|| Highlight the value changer
|| A slider bar appears.

We can change the '''ADC''' value by scrolling the pointer.
|-
|| 
|| '''ADC''' reading 0 represents the minimum '''resistance''' value of the '''thermistor'''.

'''ADC''' reading 1023 represents the maximum '''resistance''' value of the '''thermistor'''.
|-
|| Increase the value of Atemp

Highlight the states of Yheat and Yfan
|| Slowly increase the value of '''Atemp'''.

We can observe the states of '''Yheat''' and '''Yfan''' will be the same until it reaches 900.
|-
|| Decrease the value of Atemp

Highlight the states of Yheat and Yfan
|| Once it goes above 900 the state of '''Yheat''' will be 1 and '''Yfan''' will be 0.

These states will be the same until the '''ADC''' value goes below 800.
|-
|| Click Simulate -> Halt simulation >> Click Simulate -> Simulation Mode
|| Now, turn '''off''' the '''simulation mode'''.

For that, click '''Simulate''' and then on '''Halt Simulation.'''

Then click '''Simulate''' and '''Simulation Mode.'''
|-
|| 
|| Now let us '''compile''' the '''logic'''.

The detailed steps on how to '''compile''' and save the '''logic''' are explained in the earlier tutorials. 
|-
|| Click on Settings >> Click on Microcontroller >> Select AVR ATmega16 40-PDIP 

Click on Settings >> Click on MCU parameters >> Change Crystal frequency to 16
|| Click on '''Settings''' and select the '''microcontroller AVR ATmega16 40-PDIP.''' 

Adjust its '''parameters''' as shown here.
|-
|| Double-click on Yfan in I/O list >> Select PC6 >> Click OK button

Double-click on Yheat in I/O list >> Select PC7 >> Click OK button
|| Assign '''pin PC6''' to '''Yfan''' and '''PC7''' to '''Yheat''' as shown.

And '''PC7''' to '''Yheat'''.

|-
|| Double-click on Atemp in I/O list >> Select PA7 >> Click OK button

|| Double-click on '''Atemp '''in the I/O list.

'''I/O pin''' dialog box opens.

We can see there are only''' Port A '''pins as they are the '''ADC pins'''.

Select '''PA7''' and click the '''OK''' button.
|-
|| Click on Compile >> Click on Compile >> Go to Desktop/LDmicro folder >> Rename it as ‘adc.hex’ >> Click on Save.

Click '''OK''' button
|| '''Compile''' the '''logic''' as '''adc.hex'''
|-
|| Click on File >> Click on Save >> Go to Desktop/LDmicro folder >> Rename it as ‘adc.ld’ >> Click on Save
|| Then save the '''ladder diagram''' as '''adc.ld.'''
|-
|| 
|| We will now see the working of this '''logic''' on hardware.
|-
|| Connect Mainboard to PC using USBasp

laptop-usbasp.jpg

|| Connect the '''Mainboard''' to your laptop using '''USBasp'''.

Turn '''on''' the '''power supply'''.
|-
|| Open terminal >> Type cd Desktop/LDmicro >> Press ENTER >> type ‘'''avrdude -c usbasp -p m16 -U flash:w:adc.hex’ '''>> Press ENTER
|| Open the '''Terminal''' by pressing '''CTRL+ALT+T''' keys simultaneously.

Go to the folder where you have saved the '''hex file'''.

Type the '''command''' as shown to upload the '''hex file''' to the '''Mainboard'''.
|-
|| Remove the '''USBasp''' connection from the laptop.
|| Turn '''off''' the '''power supply'''.

Remove the '''USBasp''' connection from the laptop.

This will prevent any hardware damage.
|-
|| adc.png - connect as explained in the narration 
|| Let us see the connection details now. 
|-
|| adc.png - connect as explained in the narration 
|| Power the '''Heater module''' through '''relimate connectors''' from the '''Mainboard'''.

Connect '''pin PA7 '''of the '''Mainboard''' to''' temp MCU pin''' of the '''Heater module'''.

Connect '''pin PC7''' of the '''Mainboard''' to '''heat MCU pin''' of the '''Heater module'''.

Connect '''pin PC6''' of the '''Mainboard''' to fan '''MCU pin''' of the '''Heater module'''.

Make the connections as shown in the picture.
|-
|| Turn on the power
|| After making all the connections properly, turn '''on''' the '''power supply'''.
|-
||Point as explained in the narration 
|| Depending on the initial temperature either the fan or '''resistor''' starts heating up.

For the first time we can observe that '''Heaton LED '''is turned '''ON'''.

This is because its temperature of the heating element is low.
|-
|| Point to FanOn LED
|| After sometime when the '''resistor''' gets heated up, the fan will turn '''ON'''.

It is also indicated by '''FanOn LED'''.
|-
|| 
|| Again when the '''resistor''' cools down, the '''resistor''' starts heating up.
|-
|| 
|| Thus the process continues depending on the temperature of the '''resistor'''.
|-
|| 
|| Note that initially the fan might turn '''on''' if the '''resistor''' is already heated up.
|-
|| Turn off the power
|| Turn '''off''' the '''power supply'''.
|-
|| 
|| This brings us to the end of this tutorial.

Let us summarize.
|-
|| Slide 8: Summary
* A/D converter read instruction


|| In this tutorial we learnt about working of '''A to D converter read''' instruction.

|-
|| Slide : Assignment

Change the limit values :
* If ADC value < 750, 

Output: fan is ON and heat is OFF
* If ADC value > 950, 

Output: fan is OFF and heat is ON
|| As an assignment, change the limit values and repeat the experiment.

If '''ADC''' value < 750, the fan should turn '''on''' and the heating element should turn '''off'''.

If ADC value > 950 , the fan should turn '''off''' and the heating element should turn '''on'''.
|-
|| Slide 9:

About Spoken Tutorial project
|| The video at the following link summarises the Spoken Tutorial project.

Please download and watch it
|-
|| Slide 10:

Spoken Tutorial workshops
|| The''' Spoken Tutorial Project''' team:
* conducts workshops using spoken tutorials and
* gives certificates on passing online tests.

For more details, please write to us
|-
|| Slide 11:

Forum for specific questions:
|| Please post your timed queries in this forum.

|-
|| Slide 12:

Forum for specific questions:
|| Do you have any general / technical questions on OpenPLC?

Please visit the FOSSEE forum and post your question.
|-
|| Slide 13:

Acknowledgement
|| Spoken Tutorial Project is funded by MHRD, Government of India.
|-
|| Slide 14:

Thank you slide
|| This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay.

And this is Harsha Priyanka from FOSSEE team, signing off.

Thanks for watching.
|-
|}