Difference between revisions of "OpenPLC-version1-with-LDmicro/C2/Simulation-and-Compilation/English"

Learning Objectives

• Simulate a ladder diagram
• Compile a ladder diagram in LDmicro

• Simulate a ladder diagram and
• Compile a ladder diagram in LDmicro

System Requirements

• Ubuntu Linux 18.04 operating system
• LDmicro

• Ubuntu Linux 18.04 operating system
• LDmicro

• How to create a ladder diagram in LDmicro
• If not, please refer to the relevant tutorials in this series from Home | spoken-tutorial.org

• How to create a ladder diagram in LDmicro.
• If not, please refer to the relevant tutorials in this series on this website.

LDmicro - Simulator

• LDmicro has an in-built simulator
• It helps us to verify ladder diagram before experimenting on the actual hardware.
• It reduces the hardware damage due to improper code

• LDmicro has an in-built simulator.
• It helps us to verify ladder diagram before experimenting on the actual hardware.
• It reduces the hardware damage due to improper code.

We will use the ladder diagram file, sample.ld which we created earlier.

• The file sample.ld used in this tutorial is available in the Code files link of this tutorial page.
• Please download and use them while practising

Please download and use them while practising.

Select the file

Click OK button

Select the file sample.ld from the location where you have saved.

The cursor also disappears.

We can’t place an instruction in the Simulation Mode.

Highlight first rung

The instructions that are not energized appear in gray color.

This is because there is a switch in between the positive rail and LED1.

For LED1 to be energized, switch should be ON.

i.e, It should be given value 1.

Double click on ‘switch’ in the editor window and highlight the I/O list

1. Double-click on the list that appears at the bottom of the screen.

We can see that the state changes to 1.

2. Otherwise, double-click on appropriate instruction in the ladder diagram.

1. Simulate -> Start Real Time Simulation or
2. Single cycle option.

If you choose ‘Single Cycle’ option, the PLC cycles only for one time.

Highlight first rung

Now we can observe that the first rung is energized.

That is, LED1 is glowing.

Highlight first rung

We can see that the LED1 is still glowing even after the switch is off.

It means that input changes are not reflected.

Use the ‘Single Cycle’ option when you want to debug the program step by step.

We can observe that the state of LED1 changes to 1 immediately.

Thus, the outputs gets auto-updated according to the input changes.

This will turn off the simulation mode.

It includes

1. reading the input states
2. executing the program
3. updating the outputs

1. reading the input states,
2. executing the program and
3. updating the outputs.

Click on MCU parameters

Then click on MCU parameters.

Change the cycle time to 5s

Click OK button

Change it to 5s i.e. 5000ms.

Then, click on the OK button in the top right of the window.

Click Simulate -> Start Real-time simulation

Double click on Xswitch in the I/O list

Change the state of the ‘switch’ to 1.

Instead it takes upto 5s to get its state updated.

• Microcontroller selection
• MCU Parameters
• I/O assignment

• Selection of proper microcontroller

• Setting microcontroller parameters

• Assigning ports to I/O instructions

In the menu bar, click on Settings -> Microcontroller

Select AVR ATmega16 40-PDIP

I’m using Atmel AVR ATmega16 40-PDIP.

So, I’ll select ‘AVR ATmega16 40-PDIP’.

If you are using a different microcontroller, select accordingly from the menu.

Because different microcontrollers have different hex files for the same program.

10 milliseconds is a good value for most of the applications.

• We have attached a 16 MHz external crystal in the OpenPLC hardware.
• So set crystal frequency to 16 if you are using the same hardware.
• Always set proper values.
• Otherwise it may cause communication and timers to behave inappropriately.

By default, it is in disable state.

It will be enabled only when you are using any of the serial instructions.

We will learn about this in detail when we use serial instructions.

Please remember this whenever you compile the logic.

We have changed the default names for this ladder diagram in the earlier tutorial.

Because different I/O assignment generates different hex files.

Double-click on ‘switch’ in I/O list

Select ‘PA7’

Click OK button

A pop up window opens showing the unallocated pins.

Just select a pin accordingly.

I’ll select ‘PA7’, which is the 7th pin of Port A.

Then, click on the OK button.

Select ‘PC0’

Click OK

Double-click on ‘LED2’ in I/O list

Select ‘PC1’

Click OK

Then double-click on YLED2 and assign PC1.

Rename it as ‘sample’

I’ll save it in the folder LDmicro on Desktop with the same name ‘sample.hex’.

Click on the OK button.

Let us summarize.

Summary

• Simulate a ladder diagram
• Compile a ladder diagram in LDmicro

• Simulate a ladder diagram and
• Compile a ladder diagram in LDmicro

Assignment:

• Change the cycle time to 3s and 10s
• Observe the changes while simulating

1. Change the cycle time to 3 secs and then to 10 secs
2. Observe the changes in simulation time.

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Forum questions

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Acknowledgement

Thank you slide

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

Thanks for watching.