This tutorial can change the way you observe automatic movements and can give you the necessary clues to create your own automatic systems or even make an assembly line of a product in the industry. With this tutorial, you will learn how to organize your ideas to make the automation with the grafcet level 1 tool.
Parts Required
The software used was drawio because it is a good software to develop this type of schematics and it can be used online (avoiding installations), but you can use any other software like Excel or even a paper and a pencil.
Structure
To execute the structure part, the first thing you need to know is that there are three types of steps, and all have different representations, as you can see in the image below.
- The first step is represented with a double square;
- The active step is represented with a dot under the step number;
- The inactive step is represented without the dot.
The second thing is that the transitions could have two states:
- Validated in case of (2) because the step before is active;
- Invalidated in case of (3) because the step before is inactive.
It is not always possible to make a linear grafcet to execute the automatic task that we want. For that, you can see below other different representations.
Representation of a decision. In this case, the sequence of this grafcet could be from step 1 to step 2 if the reception of the transition (1) was verified or from step 1 to step 3 if the reception of the transition (2) was verified.
Representation of parallel steps. In this case, when the reception of the transition (1) was verified, the sequence of this grafcet is from step 1 to step 2 and step 3.
Interpretation
To execute the interpretation part, the first thing that you need to know is that there are two types of actions, as you can see in the image below:
Examples of actions could be:
- Activate a motor;
- Turn on a lamp;
- Initialize a timer;
- Among others.
The receptions have two states as you can see on the image below:
True – If the reception was confirmed.
False – If the reception wasn’t confirmed.
Examples of receptions could be:
- Sensor signal;
- Button signal;
- Timer signal;
- Among others.
Application Example
An ink factory needs to transform its production line from manual to automatic. Due to its SME (Small and Medium Enterprise) as a company, the purpose of this automatic line is just to fill pails with red ink when the empty pail cross through the left sensor. When the pail is full and crosses through the right sensor it will be counted. For this, they intend to use the layout below:
| Inputs |
| Start Button |
| Sensor 1 (Left) |
| Sensor 2 (Right) |
| Outputs |
| Fill Valve |
| Conveyor Belt Motor |
The next grafcet shows a possible implementation in order to solve the problem proposed by the company:
The first post on this topic (Industrial Automation) ends here. Do not lose the next post of first steps in Industrial Automation where you will learn how to evolve from grafcet level 1 to grafcet level 2 and 3.
