3. Getting started

Getting started

Now that we have the base station connected to the PLC, it is time to get started with the building process for the production line. For that, we are going to do a few additions and explore some more components.

Clone the base station

But before we begin, let’s clone the base station and make our first copy of it. We haven’t done any change yet on the original system, so you can just close it.

Then, we can click the Load button again, select the system and make a clone. Just follow the same steps as shown in the GIF below.

Can entry and exit

The dimension of the base station and the components in the specific library have been prepared to build a production line of food cans. As you will see later, there are some special components to fill the cans or even set a lock on them. 

First of all, we will start adding a product entry and product exit element. We will place the product entry on top of the sensor in the first conveyor (B01) and the product exit at the end of the 3rd conveyor, after B03.

The product exit with the default values will work for now, but let’s adjust the product entry. We will set the interval to 0, so we will drop the cans just manually, and we will set the specific product to be dropped.

Let’s click the play button and see if we can drop a can on the conveyor. Sometimes, depending on the orientation of the product that is going to be dropped, you need to adjust the product entry. In this case, we just need to rotate it 90 degrees.

Moving the cans forward

Now that we can drop a can on the first conveyor, the next challenge is to make it move all the way from the first conveyor to the end, until the product exit removes it.

Modify the PLC code so all conveyors start moving as soon as you press the start button (S01), and stop when you press the stop button (S02). We can also turn the start light (H01) on while the conveyors are running.

You will need to check the IO list or the PLC connections to know which inputs and outputs you need to use.

As you can see, you need to reset the safety circuit each time you start the emulation, in order to get power on the conveyors. You can do that by pressing the blue button (S05). We will see why this happens in the next chapter.

Safety Circuit

The base station is already equipment with safety devices, including an emergency stop button (NS01), a safety relay (SR01), a reset safety button (S05) and an auxiliary contactor (K01). The connections are made following standard safety recommendations when using this kind of safety equipment.

The functionality is quite simple: at any time, if the emergency button is pressed, the K01 contactor will open and the S05 light will turn on. Because all motor contactors for the conveyors are connected through K01(see right side of the picture above), the motors will stop immediately, even if the PLC outputs are on.

Let’s test the system again and see how the conveyors won’t move if the safety circuit is not ok (Blue light off).

A good practice is to use the digital input of the safety circuit to stop the movement as well, so the PLC outputs are set to False if the emergency button is pressed.

Challenge

It is time to play around with the station and do some programming. Can you make a PLC program so the station stops the cans for a few seconds on each sensor? Can you also make it so the next can does not move until the previous one has gone through all conveyors?