View source for OpenPLC-with-LDmicro/C3/RTO-Timer-Instruction/English


{| border="1"
|-

| align=center| '''Visual Cue'''
| align=center| '''Narration'''
|- 
|| Slide 1: 
|| Welcome to the spoken tutorial on '''RTO timer instruction'''.
|- 
|| Slide 2: Learning Objectives
* Retentive Delayed turn ON (RTO) timer

|| In this tutorial we’ll learn about working of '''Retentive Delayed Turn ON timer'''.

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

|| 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

|- 
|| Slide 4: Pre-requisites
* Working of a Contact and a Coil
* If not, please refer to the relevant tutorials from [https://spoken-tutorial.org/ Home | spoken-tutorial.org]


|| 
* To follow this tutorial, you should know the working of a '''Contact''' and a '''Coil'''.
* 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.
|- 
|| Open the LDmicro 
|| Let us open '''LDmicro'''.
|- 
|| Insert ‘Instructions -> Insert Contact’ >>

Place the cursor to the right of the contact >>

Insert ‘Instructions -> Insert Coil’
|| Insert a '''Contact''' and a '''Coil''' as shown.
|- 
|| Double-click on contact >> Type switch in name box >> Click OK button
|| Rename the Contact as '''‘switch’.'''

|- 
|| Double click on the coil >> Rename it as ‘LED1’ >> Click OK button
|| Then rename the '''Coil''' as '''‘LED’'''.

|- 
|| Place the cursor to the right of the contact >> Click Instructions -> Timers -> Insert RTO
|| We will now add a '''Retentive Delayed turn on timer''' to the right of '''Xswitch'''.

For that, place the cursor to the right of '''Xswitch'''.

Click on '''Instructions''' then '''Timers''' and then '''Insert RTO.'''
|- 
|| Double-click on Tnew >> Type RTO in the name box >> Type 5000 in the delay box >> Click the OK button
|| Rename it as ‘'''RTO’''' and enter the delay as '''5s'''.

Note that the name will be prefixed by '''T''' by default.

Click the '''OK''' button.
|- 
|| 
|| 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 Xswitch, YLED and TRTO in the IO list
|| Initially the state of '''Xswitch''', '''YLED''' and '''TRTO''' are 0.
|- 
|| Double click on Xswitch
|| Double click on '''Xswitch''' to change the state to 1.

We can observe that the state '''TRTO''' is '''20ms'''.
|- 
|| Double click on Xswitch
|| Within '''5s''' change the state of '''Xswitch''' back to 0.
|- 
|| Highlight the state of TRTO
|| We can observe that the state of '''TRTO''' doesn’t go to 0. 

Instead it shows the accumulated '''delay''' value just before '''Xswitch''' is 0.
|- 
|| Double click on Xswitch in the IO list

Highlight the state of TRTO
|| Change the state of '''Xswitch''' to 1.

We can observe that the '''timer''' starts.

The count starts from where it was before and not from 0.
|- 
|| Highlight the state of TRTO and YLED
|| After '''5s''' the state of '''YLED''' changes to 1 and '''TRTO''' to 4.990s
|- 
|| Double click on Xswitch
|| Now change the state of '''Xswitch''' to 0.
|- 
|| Highlight the state of TRTO and YLED
|| We can observe neither '''YLED''' nor '''TRTO''' changes its state.
|- 
|| 
|| This is because the '''RTO timer''' retains its state when '''Xswitch''' turns 0.
|- 
|| 
|| Thus it must be '''reset''' manually using the '''RESET''' instruction.


We will now see how to '''RESET'''.
|- 
|| 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.'''
|- 
|| Click Edit -> Insert rung below
|| Insert a new rung below.
|- 
|| Place the cursor near the new rung >> Click Instructions -> Insert Contact >> Place the cursor to the right of the contact >> Click Instructions -> Insert Reset 
|| Place a '''Contact''' and '''RESET''' instruction in the new '''rung''' as shown.
|- 
|| Double click on Xnew >> Type reset in the name box >> Click the OK button
|| Rename the '''Contact''' as '''‘reset’'''.
|- 
|| Double-click reset instruction
|| Now double-click on '''RESET''' instruction.
|- 
|| Highlight the type column
|| Under the column '''Type''' we can find two options '''Timer''' and '''Counter'''.

That means with this instruction we can reset only '''timer''' and '''counter variables'''.

By default, it is set to '''Timers'''. 

Don’t change it.
|- 
|| Type RTO in the name box
|| The name should be the name of the '''timer variable''' that needs to be '''reset'''.

So type '''RTO'''.
|- 
|| Click the OK button
|| Click the '''OK''' button.
|- 
|| Click Simulate -> Simulation mode >>

Click Simulate -> Real-time simulation
|| Start '''real-time simulation''' as shown.
|- 
|| Double click on Xswitch
|| Change the state of '''Xswitch''' to 1.
|- 
|| Highlight the state of TRTO
|| After '''5s''' the state of '''TRTO''' changes to '''4.990s.'''

Change the state of '''Xswitch''' back to 0.
|- 
|| Double click on Xreset 
|| Now change the state of '''Xreset''' to 1.
|- 
|| Highlight the state of TRTO
|| We can observe the '''timer TRTO''' '''resets'''. 
|- 
|| Click Simulate -> Halt Simulation >> Click Simulate -> Simulation Mode
|| Turn '''off''' the '''simulation mode''' as shown.
|- 
|| 
|| 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 Xswitch in I/O list >> Select PC0 >> Click OK button

Double-click on Xreset in I/O list >> Select PC0 >> Click OK button

Double-click on YLED in I/O list >> Select PA0 >> Click OK button
|| Assign '''pin PC0''' to '''Xswitch''' and '''PC1''' to '''Xreset'''.

Assign '''pin PA0''' to '''YLED'''.
|- 
|| Click on Compile >> Click on Compile >> Go to Desktop/LDmicro folder >> Rename it as ‘timeron.hex’ >> Click on Save.

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

laptop-usbasp.jpg

Text box: Turn on the power supply
|| 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:rto.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.
|- 
|| rto.png
|| Let us see the connection details now. 
|- 
|| rto.png which shows all the connections as per the narration

|| Connect '''GND pin''' of the red '''LED''' of '''Traffic Light module''' to '''GND''' of the '''Mainboard'''.

Then connect the '''+5V pin''' of the red '''LED''' to '''PA0 pin''' of the '''Mainboard'''.
|- 
|| rto.png which shows all the connections as per the narration
|| Connect '''GND''' and '''5V''' of '''Switchboard''' to '''GND''' and '''5V''' of the '''Mainboard''' respectively.

Connect '''NO1''' to '''PC0''' of the '''Mainboard'''.

Then, connect '''NO2''' to '''PC1''' of the '''Mainboard'''.

Make the connections as shown in the picture.
|- 
|| Turn on the power supply.
|| After making all the connections properly, turn '''on''' the '''power supply'''.
|- 
|| Point to red '''LED'''
|| Initially the red '''LED''' will not glow.
|- 
|| Press the switch '''NO1''' for 5 seconds
|| Press the switch '''NO1'''.

Remember '''NO1''' should be pressed for at least '''5s''' for '''LED''' to turn '''ON'''.
|- 
|| Red '''LED''' glows.
|| The red '''LED''' should turn '''ON 5s''' after the '''NO1''' is pressed.
|- 
|| Release the switch '''NO1'''
|| Once we release the '''NO1''' it doesn't turn '''off''' the red '''LED'''.
|- 
|| Release the switch '''NO2'''
|| For that we need to press the switch '''NO2'''.
|- 
|| 
|| Thus, an '''RTO timer''' retains the accumulated value even after the switch is released.
|- 
|| Turn off the power supply
|| Turn '''off''' the '''power supply'''.
|- 
|| 
|| This brings us to the end of this tutorial.

Let us summarize.
|- 
|| Slide 5: Summary
* Retentive Delayed turn ON (RTO) timer

|| In this tutorial we’ll learnt about working of '''Retentive Delayed turn ON timer'''

|- 
|| Slide 6: Evaluation

1. RES instruction is used with:
* RTO timer
* TON timer
* TOFF timer
* all of these

2. An RTO timer retains the present accumulated value when the rung goes false* True
* False

3. What timer instruction would be best suited for the below process?

Track the time to make a product.

It needs to track even if the process is halted and then started again.* TON
* TOFF
* RTO

|| Here are some self assessment questions for you.

1. RES instruction is used with_______

The options are
* '''RTO timer'''
* '''TON timer'''
* '''TOFF timer'''
* all of these

2. An '''RTO timer''' retains the present accumulated value when the '''rung''' goes false
* True or
* False

3. What timer instruction would be best suited for the below process?

Track the time to make a product.

It needs to track even if the process is halted and then started again.

The options are:
* '''TON'''
* '''TOFF'''
* '''RTO'''

|- 
|| Slide 7: Answers to Assignment
# RTO timer
# True
# RTO

|| Now let us look at the answers.

The answer to the first question is '''RTO timer'''

The answer to the second question is '''true'''.

The answer to the third question is '''RTO'''.
|- 
|| Slide 8:About Spoken Tutorial project
|| The video at the following link summarises the Spoken Tutorial project.

Please download and watch it
|- 
|| Slide 9:

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 10:

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

|- 
|| Slide 11:

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

Please visit the FOSSEE forum and post your question.
|- 
|| Slide 12:

Acknowledgement
|| Spoken Tutorial Project is funded by MHRD, Government of India.
|- 
|| Slide 13:

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.
|-
|}