View source for OpenPLC-with-LDmicro/C2/Internal-Relay-and-Output-pin/English


{| style="border-spacing:0;"
| style="border:1pt solid #000000;padding:0.176cm;"| <center>'''Visual Cue'''</center>
| style="border:1pt solid #000000;padding:0.176cm;"| <center>'''Narration'''</center>

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 1: 
| style="border:1pt solid #000000;padding:0.176cm;"| Welcome to the spoken tutorial on '''Internal Relay and Output pin'''

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 2: Learning Objectives

Types of sources available for Contacts/Coils

* Internal Relay
* Output pin

| style="border:1pt solid #000000;padding:0.176cm;"| In this tutorial we will learn about,

* Types of sources available for '''Contacts/Coils'''.
* (i.e) '''Internal Relay''' and '''Output pin.'''

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 3: System Requirements

* Ubuntu 18.04''' '''OS
* LDmicro
* OpenPLC Mainboard
* 24V, 2A SMPS
* USBasp programmer
* Traffic Light module
* Switchboard module

| style="border:1pt solid #000000;padding:0.176cm;"| To record this tutorial I am using:

* '''Ubuntu Linux 18.04''' operating system
* '''LDmicro'''
* '''OpenPLC Mainboard'''
* '''24V, 2A SMPS'''
* '''USBasp''' programmer
* '''Traffic Light module''' and
* '''Switchboard module'''

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 4: Pre-requisites

* Normal Contact and Coil
* Negated Contact and Coil

| style="border:1pt solid #000000;padding:0.176cm;"| 
* To follow this tutorial, you should know the working of 

# '''Normal Contact''' and '''Coil'''
# '''Negated Contact''' and '''Coil'''

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

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 5: Prerequisites - Hardware setup

hardware-prerequisite.jpg
| style="border:1pt solid #000000;padding:0.176cm;"| Connect''' SMPS''' and '''USBasp''' to the '''Mainboard''' as shown in the picture.

Keep these connections throughout this tutorial.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| First we will understand the working of an '''Internal Relay'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 5: Internal Relay

* It can be thought of as a variable inside a PLC memory bit
* It does not affect the external I/O’s of the PLC

| style="border:1pt solid #000000;padding:0.176cm;"| 
* '''Internal relay''' can be thought of as a '''variable''' inside a '''PLC memory bit'''.
* It does not affect the external '''I/O'''s of the '''PLC'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Open LDmicro
| style="border:1pt solid #000000;padding:0.176cm;"| Let us open '''LDmicro'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Insert ‘Instructions -> Insert Contact’ 

>> Place the cursor to the right of the contact >> Insert ‘Instructions -> Insert Coil’
| style="border:1pt solid #000000;padding:0.176cm;"| Insert a '''Contact '''from '''Instructions.'''

Then to the right of it, insert a '''Coil''' as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the Contact >> Rename the contact as ‘switch’ >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Rename the '''Contact''' as''' ‘switch’.'''

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the coil >> Select Internal Relay >> Rename it as ‘relay’ >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Double-click on the '''Coil'''.

In the ‘'''Source'''’ column select ‘'''Internal Relay'''’.

Then rename it as ‘'''relay'''’.

Click the '''OK''' button.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Highlight the coil
| style="border:1pt solid #000000;padding:0.176cm;"| We can see that '''‘R’''' is prefixed instead of '''‘Y’''' in the name which indicates '''relay'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click ‘Edit -> Insert Rung After’
| style="border:1pt solid #000000;padding:0.176cm;"| Let us add a new rung after the current rung.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Insert ‘Instructions -> Insert Contact’ >> Place the cursor to the right of the contact >> Insert ‘Instructions -> Insert Coil’
| style="border:1pt solid #000000;padding:0.176cm;"| Insert a '''Contact''' and a '''Coil''' in the newly added rung as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the contact >> Select Internal Relay >> Rename the contact as ‘switch’ >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the '''Contact'''.

In the '''‘Source’''' column select '''‘Internal Relay’'''.

Then rename it as '''‘relay’'''.

Click the '''OK''' button.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Highlight ‘Rrelay’ in the IO list
| style="border:1pt solid #000000;padding:0.176cm;"| In the '''I/O''' list we can observe there is only one '''‘Rrelay’'''.

Both '''Contact''' and '''Coil''' are represented by the same '''internal relay'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the coil >> Rename it as ‘LED’ >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Now rename the '''Coil''' as ‘'''LED’''' as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| We will now check the working of this '''logic'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click ‘Simulate -> Simulation mode’ >> Click ‘Simulate -> Real-time simulation’
| style="border:1pt solid #000000;padding:0.176cm;"| Let us turn '''on''' the '''simulation mode'''.

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

Next, start '''real-time simulation''' as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Highlight the state of Xswitch, Rrelay and YLED in the I/O list
| style="border:1pt solid #000000;padding:0.176cm;"| Initially the state of '''Xswitch, YLED '''and''' Rrelay''' are 0.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double-click on Xswitch
| style="border:1pt solid #000000;padding:0.176cm;"| Change the state of '''Xswitch''' to 1.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Highlight the state of Rrelay and YLED
| style="border:1pt solid #000000;padding:0.176cm;"| We can observe that the state of '''‘YLED’''' and '''‘Rrelay'''' have changed to 1.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double-click on Rrelay

Highlight ‘Rrelay’ in the I/O list
| style="border:1pt solid #000000;padding:0.176cm;"| Now double click on '''Rrelay'''.

We can notice that we are not able to change the state of '''Rrelay'''.

This is because the '''Internal relay''' operates in the internal '''logic''' of the '''PLC'''.

It does not operate on the '''I/O pins''' directly.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click Simulate -> Halt Simulation >> Click Simulate -> Simulation Mode
| style="border:1pt solid #000000;padding:0.176cm;"| Now, turn '''off''' the '''simulation mode'''.

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

Then click '''Simulate''' and '''Simulation Mode.'''

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| Now let us '''compile''' the '''logic'''.

The detailed steps on how to '''compile''' and save the '''logic''' are explained in the earlier tutorials. 

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click on Settings >> Click on Microcontroller >> Select AVR ATmega16 40-PDIP 

Click on Settings >> Click on MCU parameters 

>> Change Crystal frequency to 16
| style="border:1pt solid #000000;padding:0.176cm;"| Click on '''Settings''' and select the '''microcontroller AVR ATmega16 40-PDIP.''' 

Adjust its '''parameters''' as shown here.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double-click on Xswitch in I/O list >> Select PC0 >> Click OK button

Double-click on YLED in I/O list >> Select PA0 >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Assign '''PC0 pin''' to '''‘Xswitch’''' and '''PA0''' to '''‘YLED’'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double-click on Rrelay in the I/O list

Highlight the text in the dialog box

>> Click the OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Double-click on '''Rrelay''' in the '''I/O''' list.

A dialog box opens.

It says that '''‘Can only assign pin number to input/output pins’'''.

Recall that '''Internal relay''' represents a '''variable''' inside '''PLC memory'''. 

Click on the '''OK''' button.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| Thus working of this example is similar to the '''‘Normal Contact’''' example.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| So we will skip the hardware part.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click on File >> Click on Save >> Go to Desktop/LDmicro folder >> Rename it as ‘internalrelay.ld’ >> Click on Save
| style="border:1pt solid #000000;padding:0.176cm;"| Save the file as '''‘internalrelay.ld’ '''as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| We will now learn about the source type '''‘Output''' '''pin’''' of the '''contact'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click File >> Click New
| style="border:1pt solid #000000;padding:0.176cm;"| Open a new file in '''LDmicro'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Insert ‘Instructions -> Insert Contact’ >> Place the cursor to the right of the contact >> Insert ‘Instructions -> Insert Coil’
| style="border:1pt solid #000000;padding:0.176cm;"| Insert a '''Contact''' and a '''Coil '''as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the Contact >> Rename the contact as ‘switch’ >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Rename the '''Contact''' as ‘'''switch’''' 

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the Coil >> Rename it as ‘LED1’ >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Then rename the '''Coil''' as ‘'''LED1'''’.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click Edit -> Insert Rung After >> Place the cursor in the newly added rung >> Click ‘Instructions -> Insert Contact’ >> Place the cursor to the right of the contact >> Insert ‘Instructions -> Insert Coil’
| style="border:1pt solid #000000;padding:0.176cm;"| Insert a rung below.

Again, insert a '''Contact''' and a '''Coil''' in the newly added rung.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the contact >> Select Output pin >> Rename the contact as ‘LED1’ >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the '''Contact'''.

In the '''‘Source’''' column select '''‘Output pin’'''.

Then rename it as '''‘LED1’'''.

Click the '''OK''' button.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Highlight the name of the contact viz. YLED1
| style="border:1pt solid #000000;padding:0.176cm;"| We can observe the name of the '''Contact''' is prefixed by '''Y '''and not''' X.'''

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double click on the coil >> Check the ‘Negated’ box >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| Double-click on the '''Coil'''.

Check the '''‘Negated’''' box and rename it as '''LED2'''.

Click the '''OK''' button.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| We will now check the working of this '''logic'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click ‘Simulate -> Simulation mode’ >> Click ‘Simulate -> Real-time simulation’
| style="border:1pt solid #000000;padding:0.176cm;"| Start '''real-time simulation''' as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Highlight the states of all the instructions
| style="border:1pt solid #000000;padding:0.176cm;"| Initially the state of '''Xswitch''' and '''YLED1''' are 0 and '''YLED2''' is 1.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Double-click on Xswitch

Highlight the state of YLED1 and YLED2
| style="border:1pt solid #000000;padding:0.176cm;"| Now change the state of '''Xswitch''' to 1.

We can observe that the state of the '''YLED1''' changes to 1 and '''YLED2''' to 0.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| That is the output of '''YLED1''' is given as input to '''YLED2'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click Simulate -> Halt Simulation

>> Click Simulate -> Simulation Mode
| style="border:1pt solid #000000;padding:0.176cm;"| Turn '''off''' the '''simulation mode''' as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| Let us '''compile''' the '''logic'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click on Settings >> Click on Microcontroller >> Select AVR ATmega16 40-PDIP 

Click on Settings 

>> Click on MCU parameters >> Change Crystal frequency to 16
| style="border:1pt solid #000000;padding:0.176cm;"| Click on '''Settings''' and select the '''microcontroller AVR ATmega16 40-PDIP.''' 

Adjust its '''parameters''' as shown here.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Highlight Xswitch pin number

Double-click on YLED1 in I/O list >> Select PA0 >> Click OK button

Double-click on YLED2 in I/O list >> Select PA1 >> Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| We can observe that '''Xswitch''' has already been assigned '''pin PC0'''.

Now, assign '''pin PA0''' to '''‘YLED1’''' and '''PA1''' to '''‘YLED2’'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click on Compile >> Click on Compile >> rename it as ‘output-pin.hex’ >> Go to Desktop/LDmicro folder >> Click on Save.

Click OK button
| style="border:1pt solid #000000;padding:0.176cm;"| '''Compile''' the '''logic''' as '''‘outputpin.hex’''' as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Click on File >> Click on Save >> Rename it as ‘outputpin.ld’ >> Go to Desktop/LDmicro folder >> Click on Save
| style="border:1pt solid #000000;padding:0.176cm;"| Then save the '''ladder diagram''' as '''‘outputpin.ld’''' as shown.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| Now we will see the working of this '''logic''' on hardware.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Connect Mainboard to PC using USBasp

laptop-usbasp.jpg

| style="border:1pt solid #000000;padding:0.176cm;"| Connect the '''Mainboard''' to your laptop using '''USBasp'''.

Turn '''on''' the '''power supply'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Open terminal >> Type cd Desktop/LDmicro >> Press ENTER >> type ‘'''avrdude -c usbasp -p m16 -U flash:w:outputpin.hex’ ''' >> Press ENTER
| style="border:1pt solid #000000;padding:0.176cm;"| 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'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Remove the '''USBasp''' connection from the laptop.
| style="border:1pt solid #000000;padding:0.176cm;"| Turn '''off''' the '''power supply'''.

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

This will prevent any hardware damage.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| outputpin.png
| style="border:1pt solid #000000;padding:0.176cm;"| Let us see the connection details now. 

|-
| style="border:1pt solid #000000;padding:0.176cm;"| outputpin.png
| style="border:1pt solid #000000;padding:0.176cm;"| Connect '''GND''' and 5V of '''Switchboard''' to GND and 5V of the '''Mainboard''' respectively.

Then connect '''NO1''' of the '''Switchboard''' to '''PC0''' of '''Mainboard'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| outputpin.png

Point to the connections
| style="border:1pt solid #000000;padding:0.176cm;"| Beside the yellow '''LED''' of '''Traffic Light module''', you will see a '''+5V pin'''.

Connect this '''+5V pin''' to '''5V''' of the '''Mainboard'''.

Connect the '''‘EN' pin''' to the '''GND''' of the '''Mainboard'''.

Connect the '''‘L’ pin''' to '''PA0''' of the '''Mainboard''' which represents '''YLED1'''.

Connect the '''‘Ri’ pin''' to '''PA1''' of the '''Mainboard''' which represents '''YLED2'''.

Make the connections as shown in the picture.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Switch on the power
| style="border:1pt solid #000000;padding:0.176cm;"| After making all the connections properly turn '''on''' the '''power supply'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Point to green LED
| style="border:1pt solid #000000;padding:0.176cm;"| Initially the left green '''LED''' will be glowing.

Recall that bottom '''LED''' connections should be given '''logic''' low for an '''LED''' to glow.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Point the output
| style="border:1pt solid #000000;padding:0.176cm;"| Now press the switch '''NO1'''.

The right green '''LED''' starts glowing and the left one goes off at the same time.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| Thus the output of the left green '''LED''' acts as input to the right green '''LED'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Switch off the power
| style="border:1pt solid #000000;padding:0.176cm;"| Turn '''off''' the '''power supply'''.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| 
| style="border:1pt solid #000000;padding:0.176cm;"| This brings us to the end of this tutorial.

Let us summarize

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 6: Summary

* Internal Relay
* Output pin


| style="border:1pt solid #000000;padding:0.176cm;"| In this tutorial, we learnt about different source types such as

* '''Internal Relay'''
* '''Output pin'''

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 7: Assignment

Draw a ladder logic to latch an LED

Hint:

* The LED should turn on when a switch is pressed 
* It should stay on even after it is released.

| style="border:1pt solid #000000;padding:0.176cm;"| As an assignment, draw a '''ladder logic''' to latch an '''LED'''.

Hint:

* The '''LED''' should turn '''on''' when a '''switch''' is pressed 
* It should stay '''on''' even after it is released.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 8:

About Spoken Tutorial project
| style="border:1pt solid #000000;padding:0.176cm;"| The video at the following link summarises the Spoken Tutorial project.

Please download and watch it

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 9:

Spoken Tutorial workshops
| style="border:1pt solid #000000;padding:0.176cm;"| The''' Spoken Tutorial Project''' team:

* conducts workshops using spoken tutorials and 
* gives certificates on passing online tests.

For more details, please write to us

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 10:

Forum for specific questions:
| style="border:1pt solid #000000;padding:0.176cm;"| Please post your timed queries in this Forum

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 11:

Forum for specific questions:
| style="border:1pt solid #000000;padding:0.176cm;"| Do you have any general / technical questions on OpenPLC?

Please visit the FOSSEE forum and post your question.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 12:

Acknowledgement
| style="border:1pt solid #000000;padding:0.176cm;"| Spoken Tutorial Project is funded by MHRD, Government of India.

|-
| style="border:1pt solid #000000;padding:0.176cm;"| Slide 13:

Thank you slide
| style="border:1pt solid #000000;padding:0.176cm;"| 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.

|}