automatic control of the production of empanadas

Automatic control of the production of empanadas.

David Escobar Gallego ([email protected]), Ana Londono Soto ([email protected]),

Mariana Mejia Uribe ([email protected]), Elizabeth Miranda ([email protected]),

Emilio Ochoa Botero ([email protected]) and Zarith Isabella Restrepo Giraldo ([email protected])

I. INTRODUCTION

Empanadas are a typical food from the colombian

gastronomy. They are made of a corn dough in the shape

of a half moon and filled with sweet or salty that is fried

in oil. It es estimated that about 12 millions empanadas

are eaten every day in Colombia (including all kinds of

these. [2]. Furthermore, Santiago Romero, co-founder

of ”Tıpicas Empanadas”, says that about 1.1 millions

empanadas are sold [1]. Nevertheless, Romero explains

that having a precise record of the total consumption

is quiet difficult because almost 80% of the market

are informal sellers.Veggempanada is a vegan company

who produce pre-cooked empanadas,filled with potato,

coriander and onion. These empanadas are suitable for

vegan and celiac people. This statistic reveals the great

possibility of business. I we manage to automate and

control the process, we will be able to take a significant

percentage of the market, because it would be easier for an

automated company to be successful than to informal sellers.

Three parallel processes work together to create the

Veggempanada: dough, potatoes and vegetables. Dough is

made out of corn that has been previously washed and

cooked and then is mixed with salt, cassava starch and

water.The mix is then knead to get the desired dough. In

Potatoes, these are washed, peel and smashed. Mashed

potatoes will be put together with the vegetables to make

the filling. The last of the parallel process is ”vegetables”.

Here, vegetables are washed, chopped and cooked. Finally,

in the Empanada maker machine, an injector puts filling

on the dough. After this, the dough is bend over the filling

and press to form the raw empanada. Raw empanadas

leave the empanada maker machine to be fry and pack in

bags and boxes for distribution. Costumers are retailers and

wholesalers who sells the pre-cooked empanadas to the final

costumer.

Nowadays, industrial production of empanadas are based

on semiautomatic processes, which generates bottlenecks

and delays in the different lines of the process. Moreover,

semiautomatic process leads to higher cost of operation and

maintenance. Automation of the production system entails

to reduce time, mistakes and costs associated to workforce.

Efficiency and the capacity of production are improved.

Next, the description of the production process of the

empanada will be presented, as well as the sub-processes

that are required to arrive at the desired product. Also,

the diagram of the flow of material of the process, the

layout of the Veggempanada company and the reason for

the location of the machines in this one. The instrumentation

is presented by means of a SCADA-type diagram together

with a description of the sensors and actuators involved in

developing the production process and the type of PLC and

acquisition systems used for this purpose. In the same way,

the protocol and the finite state machine are described for

each machine participating in the production process, as well

as the implementation of each of these in the PLCs and their

man-machine interface to supervise the development process.

Attached you will find the technical data of the sensors,

actuators, PLC and acquisition system used.

II. PROCESS DESCRIPTION

A. Process flow diagram

The process flow diagram will be found in the Appendix

A.3, this is because the large size of the image does not

allow the details of the image to be viewed.

B. Description of the production process

In the following diagram will be found how each one of

the operations are interconnected between them, that will

allow to understand the importance of the develop of the 3

parallel production lines.

C. Company layout

The main process has 4 subprocess (potatoes, vegetables,

corn and the making of the empanada itself) and the first

three of them can be done in parallel lines, so the most

efficient way to organize the machines is like it is shown

in the layout 6. It is apparently cheaper to have just one

washing machine, one pot, one mixer, or so on... but

this would limit the production capacity because of the

bottlenecks created. If we use one machine of each kind

per line instead of one for the whole process, we can do

the parallel process and improve time, money and use of

resources to produce more profits.

D. Description of Sub-process

1) Weighing:process in which the exact amount of raw

material (corn, vegetables, potatoes and species) is

passed to make a 1 ton/day batch of empanadas (to

Fig. 1. interconnection between processes

Fig. 2. Corn sub-process

achieve dairy production it is necessary to perform the

process 5 times a day (see figure 5)

2) Solid filter: in this process small solids such as stones

and sand are filtered out to prevent that the quality of

the corn that enters the plant to be compromised and,

therefore, the final product.

3) Washing: This process is crucial to ensure that all

materials are clean and disinfected. For this, water

levels, pH and the turbidity of the water must be

controled. Valves are used in the control of water levels

and concentration of acetic acid in it. A backscatter.

4) Vegetables chopping: The vegetables are cut into small

pieces so they can be mixed with the rest of the

ingredients that forms the fill.

5) Potatoes peeling: works like a washing machine for

clothes but has a special surface that sands the peel

and removes the dirt that may remain. This process

use water.

6) Cooking: each one of the raw materials is cooked in an

industrial electric pot. When the amount of ingredients

(i.e Potatoes, veggies, corn) is enough, we add water,

close the pot and cook for a specific time

Fig. 3. Potato sub-process

Fig. 4. Vegetables sub-process

7) Grind: Corn and potatoes are ground to a softer and

pliable texture.

8) Mix: ingredients that comes out from productive line of

vegetables and potato are mixed to prepare the filling

of the empanada. Corn is mixed with salt, water and

starch to make the dough.

9) Knead / dough rolling: corn dought is brought to the

exact thickness and texture for the perfect empanada.

10) making: the corn dough is filled, then bend and finally

cut in a half moon shape.

11) frying: the product is precooked in a conveyor belt

frying machine.

12) packing: after been pre-cooked, empanadas are count

and packed in plastic bags..

E. Company layout

Process machines list

1) Weighing machine.

2) Band filter.

3) Washing machine.

4) Industrial cooking pot.

5) Industrial food processor.

6) Potato peeler.

7) Mill.

8) Double helical mixer.

9) Doug roller.

10) Empanada maker.

11) Frying

12) Flow pack machine.

The location of the machines in the plant were located

considering that the 3 main processes of the process should

be developed in parallel, this in order that at the end of said

processes one could be coupled only to the main process

machine, the maker maker (machine # 10). Additionally,

Fig. 5. empanada making sub-process

Fig. 6. Layout company

the positioning of the machines considered the conveyor

belts that must go between each one, the space between the

process lines was also considered in order to be safe for those

who are going to walk between the machines.

III. INSTRUMENTATION

SCADA diagrams shows the machines and how the

sensors and actuators are located and interact with the

process. The next illustration shows an example of the

SCADA diagram for the electrical pot (fig 7).

Nevertheless, the full SCADA diagram for whole process

can be found in Appendix A.4

PLC: The selection of the PLC are based majority on the

numbers of in integrated inputs and integrated outputs. Two

types of PLC are selected, the FX3G-14MR / DS and FX3G-

24MR / DS. The first one allows 8 inputs and 6 outputs and

the second allows 14 inputs and 10 outputs.Datasheets of

those PLC can be found in appendix 6

IV. PROTOCOL

Weighing machine (Fig. 8 y 9)

1) The machine starts on off state, where all the outputs

are off.

Fig. 7. SCADA diagram of Electrical Pot

Fig. 8. FSM 1 weighing machine

2) When the start signal is send, the machine goes to

a wait state. This state will stay until the presence

sensor is activated or stop signal or global stop signal

is activated(returning to off state).

3) If the presence sensor is activated a timer starts,

making the machine start to weight.

4) Passed 5 minutes or if the maximum weight is reached,

the timer resets. The state change to tipper, where the

tipper is activated for 10 seconds to ensure all the raw

material gets off the plate.

5) After this time (10seconds) the state returns to wait.

Filter cleaner (Fig. 10 y 11)

1) The machine starts off, where all outputs are off.

2) When the start signal is on, the machine gets on

standby mode and a LED turns on indicating this state.

In this state if any stop signal is on, then the machine

goes to off state.

3) If the presence sensor at the beginning of the conveyor

TABLE I

SENSORS TABLE

Sensor MEFVariable GXWorksVariable PLC Adress Apendix

Start Start Starte

1

X000 A.1Stop SenP SenPre X001 A.1Global Stop Senw SenWe X002 A.1Weight Stop Stope X003 A.1Presence GS StopG X004 A.1

Presence Spr SenPresencia

2

X000 A.1Start Start Starte X001 A.1Stop Stop Stope X002 A.1Global Stop GS StopG X003 A.1

Start Start starte

3.1 y 3.2

X000 A.1Stop Stop stope X001 A.1Global Stop GS global stope X002 A.1Level Nmin Nmin X003 A.1Level Nmax Nmax X004 A.1Presence S1 SenPre X005 A.1pH pH pH X006 A.1

Start Start Start

4.1-4.3

X000 A.1Level Vmin Vmin X001 A.1Weight W Weight X002 A.1Level Vmax Vmax X004 A.1Stop Stop1 Stope X005 A.1Pressure P Pressure Float A.2Global Stop GS StopG X006 A.1

Start Start Start

5

X000 A.1Stop Stop Stope X001 A.1weight W Weight X002 A.1Global Stop GS StopGlob X003 A.1

Stop Stop Stope

6

X000 A.1Global Stop GS StopGlob X001 A.1Start Start Starte X002 A.1Level Lop Lop X003 A.1Weight W W X005 A.1

Start Start Start

7.1 y 7.2

X000 A.1Stop Stop Stope X001 A.1Presence P Presence X002 A.1Global Stop GS StopGlob X003 A.1

Presence S2 SenPresencia

8,1

X000 A.1Stop Stop Stope X001 A.1Global Stop GS StopG X002 A.1Start Start Starte X003 A.1Weight S1 SenPeso X004 A.1

Presence Spre SenPresencia

8,2

X000 A.1Stop Stop Stope X001 A.1Global Stop GS StopG X002 A.1Start Start Starte X003 A.1Weight Se SenPeso X004 A.1

Start Start Start

9

X000 A.1Stop Stop9 Stope X001 A.1Presence P Presence X002 A.1Global Stop GS StopGlob X003 A.1

Start Start Starte

10

X000 A.1Stop Stop Stope X001 A.1Presence P1 SenPre1 X002 A.1Presence P2 SenPre2 X003 A.1Lineal Velocity v Velocity X004 A.1Global Stop GS StopG X005 A.1

Temperature Tmin Tmin

11

X000 A.1level Nmax Nmax X001 A.1level Nmin Nmin X002 A.1Presence Sp SenPre X003 A.1Start Start Starte X004 A.1Stop Stop Stope X005 A.1Global Stop GS StopG X006 A.1Turbidity Tb SenTurbidez X007 A.1Temperature Tmax Tmax X010 A.1Level Nempty Nvaciado X011 A.1

Start Start Starte

12

X000 A.1Stop Stop Stope X001 A.1Global Stop SG StopG X002 A.1Presence SC SenCount X003 A.1Presence SP SenPacking X004 A.1

Fig. 9. BD1 weighing machine

TABLE II

ACTUATORS TABLE

Actuator MEFVariable GXWorksVariable PLC Adress Apendix

Tipper Tipp Tipper1

Y002 A.2Weighing led WeLed LedWe Y000 A.2Tippering Led TpLed LedTipp Y001 A.2

Engine M MotorVibrador

2

Y000 A.2Conveyor belt Engine MB MotorBanda Y001 A.2Waiting led L1 LedEsperando Y002 A.2Cleaning led L2 LedLimpiando Y003 A.2

Conveyor belt Engine MB MotorB

3.1 y 3.2

Y000 A.2Valve V1 ValveIn Y001 A.2Valve V2 ValveOut Y002 A.2Valve V3 ValveAcid Y003 A.2

Valve V1 Val1

4.1-4.3

Y000 A.2Valve V2 Val2 Y001 A.2Valve V34 Val34 Y002 A.2Shaft Cover Cover Y003 A.2Conveyor belt Engine M1 Engine1 Y004 A.2Engine M2 Engine2 Y005 A.2Resistance R Resis Y006 A.2

Blades Engine M Engine

5

Y000 A.2Waiting led Led1 Led1 Y001 A.2Chop led Led2 Led2 Y002 A.2stopped led Led3 Led3 Y003 A.2

Engine MR MotorR

6

Y000 A.2Conveyor belt Engine MC MotorC Y001 A.2Shaft Cover Cover Y002 A.2Valve V1 Valv1 Y003 A.2Filled led Led0 Led0 Y004 A.2stopped led Led1 Led1 Y005 A.2Peeling Led Led2 Led2 Y006 A.2Pulling out Led Led3 Led3 Y007 A.2

Mill engine M Engine

7.1 y 7.2

Y000 A.2Waiting led Led1 Led1 Y001 A.2Grind Led Led2 Led2 Y002 A.2stopped led Led3 Led3 Y003 A.2

Mixing led Ledmix LedMixing

8,1

Y000 A.2Waiting led LedWait LedWaiting Y001 A.2Mixer Engine M3 MotorMezcladora Y002 A.2Conveyor belt Engine M1 MotorBanda Y003 A.2Screw Engine M2 MotorTornillo Y004 A.2Shaft P PistonFondo Y005 A.2Metering valve VR VolvulaReguladora Y006 A.2valve V ValvulaAgua Y007 A.2

Mixing led LM LedMixing

8,2

Y000 A.2Waiting led LW LedWaiting Y001 A.2Mixer Engine MM MotorMezcladora Y002 A.2Conveyor belt Engine MB MotorBanda Y003 A.2Screw Engine MT MotorTornillo Y004 A.2Shaft P PistonFondo Y005 A.2Metering valve VG VolvulaGuiso Y006 A.2

Dough Engine M Engine

9

Y000 A.2Waiting led Led1 Led1 Y001 A.2Dough Led Led2 Led2 Y002 A.2stopped led Led3 Led3 Y003 A.2

Shaft Shaft Shaft

10

y001 A.2Injector Injector Injector y002 A.2Conveyor belt Engine MC MB y003 A.2Stopped led LedS Led1 y004 A.2Waiting led LedW Led2 y005 A.2Operation Led LedO Led3 y006 A.2

Conveyor belt Engine Min MotorBIn

11

Y000 A.2Engine Mf MotorBFitrar Y001 A.2Resistance R Resistencia Y002 A.2Valve Vin ValvulaIn Y003 A.2Valve Vout ValvulaOut Y004 A.2Frying led Lf LedFritando Y005 A.2Waiting led Le LedEsprando Y006 A.2Emptying Led Lemptying LedVaciando Y007 A.2Filling led L filling LedLlenando Y010 A.2Filled led Lfilled LedLleno Y011 A.2

Resistance R Resistence

12

Y000 A.2Shaft C Button Y001 A.2Shaft Pr Shaft Y002 A.2Shaft Cor Cutting Y003 A.2Conveyor belt Engine MB MB Y004 A.2Bags Engine Mbol Mbol Y005 A.2Filling led LC Lfilling Y006 A.2Packing led LP Lpacking Y007 A.2

belts get on, the conveyor belt gets on, the industrial

vibrator also gets on and a LED 2 indicates that the

machine is separating(state ON).

4) Because the presence sensor is at the beginning of the

conveyor belt, once the material passed that point, the

presence sensor turn off and the machines goes to a

state called ”Empty conveyor” where the conveyor belt

engine and the vibrator engine keeps active during 30

seconds, time to ensure that all material get out of

the machine. After 30 seconds the machine goes to

stand by mode.If the presence sensor actives during

the empty conveyor state the machine comes back to

Fig. 10. FSM 2 Band Filter

Fig. 11. BD2 Band Filter

the ON state.

5) When a stop or global stop signal is sent, the machines

goes direct to OFF state independent of the previous

state.

Washing machine

Fig. 12. FSM 3 Washing machine

1) The process begins at the OFF state, where all actuator

are inactivate.

2) When a start signal is sent the machines goes to stand

by mode where all actuator are off except for the ”LED

waiting” which makes explicit the state of waiting

machine for the supervisor. If the stop or global stop

are activate the machine comes back to the OFF state

3) Staying in the stand by state, there are two options: if

the Nmin and Nmax and the presence sensor are active

the machine starts to wash activating the conveyor belt

Fig. 13. BD3 Washing machine

engine and the ”Led Washing”, if there was not Nmin

the machine goes to a Fill state where the valve in

turns ON, until the water level gets to maximum level

again and the machines comes back to the stand by

mode state.

4) If the stop or global stop are activate in the washing

state, the machines goes to a water emptying state

where the valve out is turn on (because vegetables and

potatoes can not be left during a long period inside the

water) and the Led Waiting is activated. It drains all

the water during 20 seconds and goes to the OFF state

5) While being in the washing state if the pH goes upper

or equal than 7, the machine enters a Add acid state,

where the valve number 3 (the valves that allows the

acetic acid) turns on, until the pH is between 6 and 7

and comes back to the washing state

6) When the machine is washing or checking the pH if

the turbidity sensor turns on, the machine goes to the

water emptying state, drains all the water, and after 20

seconds passes to the filling state where the valve of

the water in is activate

Electrical Cooking Pot (Fig. 14 y 15)

Fig. 14. FSM 4 Electrical Pot

1) The machine start on off, where all outputs are off

except for the two relief valves (3 and 4). The Green

LED means the machine is operating and is set in

all states but ”OFF” and ”Emergency”. The Red LED

means the pot is ”OFF” or in ”Emergency” state.

Fig. 15. BD4 Cooking Pot

2) When the start signal is on, the machine goes to

standby and a green LED turns on indicating the

machine is ready to operate. If either a Stop or a

General Stop in signal comes in any state, the machine

goes to Off. In this state, cover goes on (open).

3) If there is not enough weight and the pressure inside

the pot is equal of lower than the atmospherics’s

pressure (1bar), the pot starts to fill (either with pota-

toes, corn or vegetables). If there was already enough

weight, valve 1 (H2O in) opens and the pot starts fills

with water.

4) When the Pot is in ”Pot filling” state and the weight

has been reached, state ”Add Water” goes on and valve

1 opens.

5) When the max level is reached, the FSM goes to

Cooking state, the relief valves close, the resistor

changes to ON and valve 1 equals to 0. At the same

time, a timer is set to 30min.

6) When the cooking process is over (time=30min), state

Depressurization is set, the resister is reset and relief

valves are open to release the steam. If by any reason

the pressure rise out of the limits (P >= 6bar) an

Emergency state is set and the relief valves are set too.

When the pressure equals 1 bar and someone press the

Start button again, ”Add water” is set once again.

7) In Depressurization, when is it safe to open the cover

(P=1bar), the FSM moves to ”Water Emptying”. Valves

3 and 4 remains set and Valve 2 opens to remove water.

After the Vmin sensor goes off, ”Pot emptying” is set.

8) The cover is open, valve 2 closes and the engine that

flips the pot is set. This will remain for 30s to ensure

that all the content leave the inside. Finally, Standby

mode is set and everything repeats.

Food Processor(Fig. 16)

1) Food Processor starts in ”OFF”. In this state, the engine

of the blades (M), wait indicator (Led1) and chopping

indicator (Led2) are down; while stop/emergency stop

indicator is up (Led3).

2) When Start button is pressed, state switch to Wait and

Led1 is set while Led3 is reset. Wait will continue until

the Weight sensor (P) detects the necessary weight.

3) In the moment ingredients pass by the presence sensor,

Fig. 16. FSM 5 Food Processor

Fig. 17. BD5 Food Processor

the engines of the blades will start and Led2 is going

to be on. On the other hand, Led1 is going to be reset.

4) The cycle will close when W=0 and Chopping will

turn into Wait. A Stop or General Stop signal is going

to reset everything to OFF.

Potato Peeler

Fig. 18. FSM 6 Potato Peeler

Fig. 19. BD6 Potato Peeler

1) The potato peeler starts in ”OFF”. In this state, the

conveyor belt engine (MC), metering engine (MR),

operation valve (V1), cover, water and potatoes needed

(Led0) and peeling indicator (Led2) are down; while

stop/emergency stop indicator is up (Led1).

2) When Start button is pressed, state switch to Wait, were

everything except for the conveyor belt engine (MC)

is down, and will go to standby in case the Stop or

Global Stop signal is activated.

3) For the transition to the next state (filled) it is necessary

that the weight sensor is activated, marking the nec-

essary potato weight, in this case, the operation valve

is active as well as the light (led0) indicating that the

potato peeler it is full, although, if we send the stop

or global stop signal, we will return to the wait state..

4) The peeling state has the condition Level of operation

of water (Lop), in this one the metering engine (MR)

and the LED for peeling (Led2) are up, the rest of the

actuators are down.

5) To the next state, stop peeling, it has to spent 5 minutes

before ending the peeling, all of the actuators are down,

however if we send the stop or global stop signal, we

will return to the wait state.

6) For changing to the throwing state, the angular velocity

inside the potato peeler needs to be zero, in this

moment the only two that are up are LED throwing

(Led3) and the cover.

Mill

Fig. 20. FSM 7 Mill

Fig. 21. BD7 Mill

1) The mill starts in ”OFF”. In this state, the engine of

the blades (M), wait indicator (Led1) and grinding

indicator (Led2) are down; while stop/emergency stop

indicator is up (Led3).



the Presence sensor (P) detects something.




4) The cycle will close when P=0 and Grind will turn

into Wait. A Stop or General Stop signal is going to

reset everything to OFF.

Corn, salt and starch mixer (Fig. 22)

Fig. 22. FSM 8.1 Grains mixer

Fig. 23. BD8.1 Grain Mixer

1) The machine starts in off state, where all actuators are

off

2) If the start signal is on, the stand by mode will be

active, where as same as off state all actuator are

off, but the ”Led Waiting” is ON with the purpose

of showing to the supervisor the state of the machine.

In the same way if stop or global stop signal is send

the machines comes back to the off state

3) When the presence sensor is active and the EM signal

is active (EM is a memory that saves zero when the

process passes from the out state to the stand by mode)

the machine goes to the feed state, here the conveyor

engine of the beginning of the machine turns active so

the raw material enters the process

4) Once the weigh sensor is active the systems passes

to the add water state, where as its names says, the

water valve opens letting water in to the system during

10 seconds. After that the machine goes to the add

species state, where the metering valve is active letting

specifics amounts of salt and starch passes to the mix.

5) Passed 10 seconds the machine goes to the mix state,

where the mixer engine runs, giving and homogeneous

mixed, also the ”Led mixing” turns on indicating the

machine is mixing.

6) Passed another 60 seconds the machine goes to the Out

state, where the button of the machines opens letting

the dough passes to the endless screw, in order to do

so, the shaft active, and the mixer engines keeps active

helping dough get out of the machine, also the endless

screw engines active in order to transport the dough

from the machine to the next step in the process.

7) The said above occurs during 20 seconds, then machine

comes back to the stand by mode,resetting the EM

memory.

8) If the stop or global stop signal is send during the

mix state, the machine goes back to the off state, if

its send during out state the machine waits its normal

20 seconds and directs to the stand by mode, but once

there because the stop signal is active goes direct to

the off mode. Finally if stop is send from any other

state the machines ends its normal process until it

arrives to the mix state where is directs to the off state

Potato and vegetables mixer (Ref.24)

Fig. 24. FSM 8.2 Potato and vegetables mixer

Fig. 25. BD8.2 Potato and vegetables mixer

1) This machine has a performance similar to the corn,

salt and starch, with the only difference than there

is not add water state and the add species state is

rename for stew state because instead of adding salt

this machines adds tomatoes and onions. For the above

mentioned the machine goes from the feed state to the

add stew if the weight sensor is on. The rest of states

and transitions are stay the same as corn mixer

Dough Roller

1) The Dough Roller starts in ”OFF”. In this state,

the engine of the rollers (M), wait indicator

(Led1) and rolling indicator (Led2) are down; while

stop/emergency stop indicator is up (Led3).

Fig. 26. FSM 9 Dough roller

Fig. 27. BD9 Dough roller



the Presence sensor (P) detects something.




4) The cycle will close when P=0 and Rolling will turn

into Wait. A Stop or General Stop signal is going to

reset everything to OFF.

Empanada Maker (Fig. 28 y ??)

Fig. 28. FSM 10.1 shaft empanada maker

2 FSM where designed for this machine.

For the injector:

1) The injector starts off, where everything is OFF, except

for the first LED light (Led1), which means off or

emergency stop.

2) When the start signal is on, the stand by mode will

be active, the conveyor belt engine and the ”Waiting

Led” (Led2) is ON with the purpose of showing to the

supervisor the state of the machine. In the same way if

stop or global stop signal is send the machines comes

back to the off state.

Fig. 29. FSM 10.2 Injector empanada maker

Fig. 30. BD10 Empanada maker

3) If the presence is activated, then the machine changes

to a state of Check, where the purpose is verify the

presence of rolled dough for filling it with the mixture

of smashed potatoes and stew, for this, is necessary

to turn off the conveyor belt engine and turn on a

”Operation LED” (Led3) which will remain ON for

the next state.

4) Then, if the lineal velocity is zero, we change to

a inject state, for injecting the mixture of smashed

potatoes and stew, also we restart a timer for the next

state. If stop or global stop signal is send the machines

comes back to the off state.

5) To return to a standby state, it takes 2 seconds

For the shaft:

1) The shaft starts off, where everything is OFF, except

for the first LED light (Led1), which means off or

emergency stop.

2) When the start signal is on, the stand by mode will

be active, the conveyor belt engine and the ”Waiting

Led” (Led2) is ON with the purpose of showing to the

supervisor the state of the machine. In the same way if

stop or global stop signal is send the machines comes

back to the off state.

3) If the presence is activated, then the machine changes

to a state of Check, where the purpose is verify the

presence of filled dough, for this, is necessary to turn

off the conveyor belt engine and turn on a ”Operation

LED” (Led3) which will remain ON for the next state.

4) Then, if the lineal velocity is zero, we change to a

shaft state, for cutting the empanada and shaping it,

also we restart a timer for the next state. If stop or

global stop signal is send the machines comes back to

the off state.

5) To return to a standby state, it takes 2 seconds

Fryer (Ref. 31,32, 34 y 33)

Fig. 31. FSM 11.1 resistance of the fryer

Fig. 32. FSM 11.2 valves of the fryer

Fig. 33. FSM 11.3 conveyor belt of the fryer

For this machine were divided in 3 MEF, one for the

valves, another one for the heating resistance and the last

one for the conveyor belt that let the empanada fry.

The protocol for the resistance is:

1) The resistance starts on off state.

2) When the minimum level of oil is reached and the

maximum temperature is not reached yet, the resistance

goes on.

3) If the resistance is on and there is no minimum level

of oil or it reached the maximum temperature or the

stop signal is on, the resistances goes off.

Fig. 34. BD 11 Fryer

The protocol for the valve is:

1) The valve starts off.

2) When the start signal is send, the process of fill starts,

in this state a LED turns indicating that the tank is

filling on and the feed valve opens.

3) When the minimum level and maximum is reached,

the process pass to a standby Mode.

4) In standby mode, everything gets off, except for a LED

that indicate the tank is at the operation level.

5) If the machine is on the process of fill or standby mode

and the maximum turbidity is reached then the process

goes to a emptying state.

6) In the emptying state, just a LED indicating that

indicates that is on this state turns on and the outlet

valve opens. This state stays until the tank is empty

(level sensor at the bottom of the tank gets off), when

this sensor deactivates the process of filling starts

again.

7) On filling process if stop or global stop are on, then

the machine will go off until a start signal comes on.

The protocol for the conveyor belt is:

1) The conveyor belt starts with everything off(off state).

2) When the start signal is send, the machine gets on wait

state where a LED indicates that is on this state.

3) If there is nothing at the beginning of the conveyor belt

and the minimum level and temperature are reached the

state will change from standby to feeding state. Also

if the stop or global stop signal is activated, the state

will change from wait to off.

4) On feeding process the engine of the conveyor belt and

a LED gets on. Until a stop or global stop signal is on

(letting the state change to off) or the presence sensor

send a signal (letting the state change to fry).

5) When the state is on fry, conveyor belt of the fryer and

feeding are activate, also a LED turns on indicating the

machine is frying. The rest of the outputs are off.

6) If there is no level to fry or the temperature is not at

the minimum or a stop or global stop signal is send

on fry state, the fryer gets on a slow down process.

7) On slowdown process a timer starts, the conveyor belt

of fryer continue working but the one for the feeding

stops. Passed 10 seconds (timer = 10s) if the signal of

any stop is on, the machine goes to off state, but if is

not, the state goes to standby state.

Packing machine (Ref. 35)

1) The machine starts off, where all the outputs are off.

Fig. 35. FSM 12 Packing machine

Fig. 36. FSM 12 Packing machine

2) When the start signal is send, the machine starts

feeding to a open bag, so the feeding conveyor belt

starts, also a LED gets on.

3) When a empanada passes thought the sensor, the

machine counts (changing state between feeding and

count).

4) When the sensor counts 20 empanadas, the machine

starts packing. A gate close the bottom of the hopper,

a hot press seals the bag. In this and the next 2 steps

a LED will indicate that the machine is packing.

5) Past 3 seconds packing, a cutter cuts the bag in the

middle of the sealing area. When the cutter pass the

bag, a sensor activates changing state to new bag.

6) In new bag state, a engine let a new bag put in position

to receive another batch of empanadas. After 3 seconds

the machine gets on feeding state.

Conventions

FSM:

• X: X denied

• XY : X and Y

• X + Y : X or Y

Man machine interface and SCADA

• Light green for ON

• Dark green for OFF

• Stop LED on red

Mass flow Diagram

• S: Sensors

• A: Actuators

TABLE III: Auxiliar variables

Machine Codification Variable Meaning

Weighing machinet1 timer 1

timer 1, it’s used to tipper thethings inside the weighing machineafter 5 minutes

t2 timer 2timer 2, it’s used to reposisionatethe tipper to it original state after 10 seconds

Band filtert timer

time for the conveyor belt be activeto evacuate raw materials

B Bit

Bit saves the value of 1 if it was stoppedin empty conveyor or 0 if it past throuhgempty conveyor belt to on

Washing machinet1 timer 1

timer 1, it’s used to return to,the standbymode after 90 seconds

t2 timer 2timer 2, this time is used to determine theemptying of the water tank, it takes 20 seconds

Industrial cooking pottv timer ”volcado”

the timer ”volcado” it’s used to tipper theelectric pot after 30 seconds

tc timer cookingthe timer cooking it’s used to turn off theelectric pot after 30 minutes

Potato peelert1 timer 1 timer 1, it’s used to stop the peeling after 5 minutes

t2 timer 2

timer 2, it’s used to finishing the potato throwing and restarting the standby modeafter 2 minutes

Double helical corn mixert1 timer 1

The first time it’s used (transition between addingwater and species) lets me know time I open the water valve(10 seconds), the second time, it’s the time time for passingfrom adding species to mixing (10 seconds) and third timethe 60 seconds from mixing to out

ME Memory It let’s me know when the cover of the mix was open

Double helical potato mixert1 timer 1

The time allows the transitions between statesas it’s necessary (According to the FSE)

ME Memory It let’s me know when the cover of the mix was open

Empanada maker-Injectort1 timer 1 timer 1, it’s used to stop the injection after 2 seconds

t2 timer 2timer 2, it’s used to make a separation betweenthe injections of the fill

Empanada maker-Shaftt1 timer 1 timer 1, it’s used to stop the shaft after 2 secondst2 timer 2 timer 2, it’s used to make a separation between the ”shafts”

Fryer t1 timer 1The timer indicates the transition between slow down andoff and,slow down and standby mode (10 seconds on each one)

Flow pack machineCE counter counter of empanadas per package

Cpack counter counter of the total empanadas

V. IMPLEMENTATION

FSM to PLC:

First step is declaring the variables, the following itemize

shows how variables where declared on the device column:

• Input: X###

• Output: Y###

• States: M##

Now then, on all FSM the initial state is off. So with an

open contact set with the mark 8002(this mark send a pulse

when the machine is connected) and connected to coils (one

coil per state), let all the coils on reset except for the off

state. This is made for initial state.

The programming of the FSM made with 2 steps per state:

1) The first step is declaring the outputs of the state.

In this case a open contact of the respective state is

connected to output coils (one coil per output). The

coils are on ”set” if it is a ”1” on the FSM and if

output is on ”0”, then the coil is on ”reset”.

2) The second step is the output transitions of the state.

In this case the conditions are made with contacts.

a) If the condition is denied, then a normally closed

contact must be use.

b) If the condition is ”and”, the contacts must be

serially.

c) If the condition is ”or”, the contacts must be on

parallel.

Additionally the timers, counters where made with prede-

termined functions blocks from gxworks.

Folder system

All gxworks archives have the name of the respective

machine. In ”Protocol” the FSM can be find with the machine

name.

Figure 37 shows part of the code used for the functioning

of the Electrical Pot: The first segment of code does the

Fig. 37. Example 1 of code

scaling of the analog signal from the pressure sensor.

This allows us to use this input in the control process.

”Entrada analoga” is a word type data from the sensor.

”INT TO REAL” transform it into a float. Then, using the

equation of a line, we calculate the Pressure of the system.

”R escalado” is the range of operation of the pot (0 to 7 bar).

”R escalar” is the definition of the data (R escalar=4000).

Pressure is the most important agent in the cooking process

because it can lead to a catastrophic results.

In the second section, we start with the mark ”M8002”

that permit the pass of current when the machine is

connected to a power supply. When the M8002 is set, all

the States of the FSM are reset excluding ”EstOff” (Off

state). It is also shown that actuators Val1 (H2O in), Val2

(H2O out), Cover, Engine1 (conveyor in),Engine2 (flipping

the pot), Resis (resister) and Lv (green LED) are all set to

cero (0); while Val3-4 (relief valves), Lr (red LED) are set

to 1.

In the last section, ”Wait” state y set when the FSM is in

EstOff AND the switch ”Start” has been set to 1.

The next fragment of code shows the transition from

”H2OFill” to ”Cook” and to ”DePress”:

Fig. 38. Example 2 of code

Cook is only set when we are at H2OFill and there is

a minimum level (Vmin=1) and the maximun level has

been reached (Vmax=1). When this happen, Cook is set

and H2O is reset. Moreover, in Cook state, Resis is set to

1 and Val3-4, Val1 and cover are closed. In the very first

moment Cook is on, a Pulse Timer (TP 1) is set to 30 min

(30 seconds in the example). The Boolean exit Q of TP 1

keeps a true values for PT time (PT=30s); then, using a

Normally Closed Switch in the next segment, we control

that only after TP times,”DePress” (depressurization) state

is set to 1 and cook reset to 0.

The number of sensors (with their types), actuators (with

their type, PLC and acquisition systems) will be shown below

Fig. 39. Type of sensors

Fig. 40. Type of actuators

In the figure 41, PLC2 correpsonds to a PLCFX3G Main

Units 14 I/O with 8 entries and 6 outputs and PLC1

correpsonds to a PLCFX3G Main Units 24 I/O with 14

entries and 10 outputs

VI. CONCLUSIONS

• It was possible to realize the automatic control of

the production process of vegan empanadas by im-

plementing the finite state machines using PLC with

the Gx Works2 software. This allows to reduce labor

costs, increase production capacity and also improve the

efficiency of the plant, and improves the asepticity of

the product delivered to the consumer.

• It is possible to minimize waste and bottlenecks in

the systems by implementing sensors and actuators that

control the process, this is because waiting times are

minimized and problem detection and solution is made

faster.

• Implementing a human machine interface allows the

entire process to be controlled by one person, this allows

the process to be visualized in a holistic manner where

all the variables that interact in the process can be taken

into account, which leads to improved productivity and

makes the process more sustainable.

• Even tho the process is easily optimizable, factors like

Fig. 41. Type of sensors

the cost of PLCs and machinery make this invertion

a bit higher than an informal empanada production.

However,there is a lot of room to make better and

cheaper at future and it will be more profitable.

REFERENCES

[1] ”Cada mes vendemos alrededor de 1,1 millones de empanadas”:Tıpicas Empanadas”, larepublica.co, 2019. [Online]. Available:https://www.larepublica.co/empresas/cada-mes-vendemos-alrededor-de-11-millones-de-empanadas-tipicas-empanadas-2920285 [Accessed:7- Mar- 2020].

[2] ”DOCE MILLONES DE EMPANADAS”, el-colombiano.com, 2012. [Online]. Available:https://www.elcolombiano.com/historico/docemillonesdeempanadas−PGEC210807[Accessed : 7−Mar − 2020].

automatic control of the production of empanadas

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