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Building a PLC Program That You Can Be Proud Of – Part 5

The Game of Simon
Learning all about bit manipulation and sequencers

Simon is a memory game introduced in 1978. It has four coloured buttons, each producing a particular tone when it is pressed or activated by the device. A round in the game consists of the device lighting up one or more buttons in a random order, after which the player must reproduce that order by pressing the buttons. As the game progresses, the number of buttons to be pressed increases. If the wrong button is hit the current game is over. Our game will have a high level score and a current level score.

We will be using AdvancedHMI to communicate Modbus TCP to the Automation Direct Do-More Designer Software Simulator.

Watch on YouTube : The Game of Simon Play (PLC / HMI)
Here is the end result of our program.

Note: The programs are provided free of charge and are an excellent way to learn PLC / HMI programming.

Here is a quick review of the programming series so far. If you are new to the site, we recommend reviewing the other parts in the series first. In part 1 we looked at writing PLC programs to control a traffic light using discrete bits and then using timed sequencing using indirect addressing. Part 2 used indirect addressing for inputs as well as output to control the sequence of pneumatic (air) cylinders in the program. Part 3 and 4 we returned to the traffic light application and expand our program significantly. We looked at the sequence of operation using Input, output and mask tables.

Simon Game HMI 130-min

The first thing that we will do is look at the HMI programming. Please refer to the following post for information on setting up and using AdvancedHMI software.
Create a PLC with HMI Training and Learning Environment Free

The following table is the Modbus TCP memory map to the Do-More PLC:

Coil/Register Numbers Data Addresses Type Do-More PLC Table Name
00001-09999 0000 to 270E Read-Write MC1 to MC1023 Discrete Output Coils
10001-19999 0000 to 270E Read-Only MI1 to MI1023 Discrete Input Contacts
30001-39999 0000 to 270E Read-Only MIR1 to MIR2047 Analog Input Registers
40001-49999 0000 to 270E Read-Write MHR1 to MHR2047 Analog Output Holding Registers

Simon Game HMI 100-min
Add the ModbusTCPCom control and set the IP Address. Also set the PollRateOverride to 50 so the response to our PLC is quicker.

The following map will apply to our game:
(Communication between the HMI and PLC)

40002 – MHR2 – Register – Game Sounds
40001 – MHR1 – Register – Current Game Level
40003 – MHR3 – Register – Highest Game Level
00005 – MC5 – Bit – Start/Reset Game
00001 – MC1 – Bit – Green Button Input
10001 – MI1 – Bit – Green Button Set
00002 – MC1 – Bit – Red Button Input
10002 – MI1 – Bit – Red Button Set
00003 – MC1 – Bit – Yellow Button Input
10003 – MI1 – Bit – Yellow Button Set
00004 – MC1 – Bit – Blue Button Input
10004 – MI1 – Bit – Blue Button Set

Simon Game HMI 110-min
The DataSubsciber is used to read information from the PLC and manipulate the data in the visual basic code.  We will use this to determine what sounds to play.

The following is the code for the button when hit to play the sound and the DataSubscriber1 to play the sound when the playback from the PLC is required. (Console.Beep (Frequncy (Hz), Duration (msec)))

Private Sub PilotLight1_Click(sender As Object, e As EventArgs) Handles PilotLight1.Click ‘ Green Light
     Console.Beep(415, 420)
End Sub

Private Sub PilotLight2_Click(sender As Object, e As EventArgs) Handles PilotLight2.Click ‘ Red Light
     Console.Beep(310, 420)
End Sub

Private Sub PilotLight3_Click(sender As Object, e As EventArgs) Handles PilotLight3.Click ‘ Yellow Light
     Console.Beep(252, 420)
End Sub

Private Sub PilotLight4_Click(sender As Object, e As EventArgs) Handles PilotLight4.Click ‘ Blue Light
     Console.Beep(209, 420)
End Sub

Private Sub DataSubscriber1_DataChanged(sender As Object, e As Drivers.Common.PlcComEventArgs) Handles DataSubscriber1.DataChanged
If DataSubscriber1.Value = “1” Then
     Console.Beep(415, 420) ‘ Green
ElseIf DataSubscriber1.Value = “2” Then
     Console.Beep(310, 420) ‘ Red
ElseIf DataSubscriber1.Value = “4” Then
     Console.Beep(252, 420) ‘ Yellow
ElseIf DataSubscriber1.Value = “8” Then
     Console.Beep(209, 420) ‘ Blue
ElseIf DataSubscriber1.Value = “10” Then
     Console.Beep(120, 1500) ‘ Losing Sound
ElseIf DataSubscriber1.Value = “20” Then
     For x = 1 To 8
          Console.Beep(600, 90) ‘ Winning Sound
          Threading.Thread.Sleep(20)
     Next ‘x
End If
End Sub

Simon Game HMI 120-min

We now have our HMI interface complete and can move onto the PLC programming.

Random sequence generator – MHR4
The first four bits of MHR4 will be used to generate the random sequence for each step of the pattern.
The first scan is to set (1) a bit in MHR0. This will also ensure that the rest of the bits in the word are reset (0).
The second rung will shift the bits left in the output word MHR0. This will happen once per scan of the PLC. When bit 04 turns on then bit 00 will then be turned on again. This way we will always have one of the first four bits turned on in the output word. (00, 01, 02 or 03) MHR0 is logically AND with Hex value 000F and the result is placed in MHR4.

Simon Game PLC 100-min

Start the Game
The game will be started n the leading edge of the reset button. (MC5)
All of the registers and pointers are reset to start the game.
1     is moved into the current level – MHR1
100 is moved into the Play Sequence Pointer – V1
100 is moved into the Input Sequence Pointer – V2
100 is moved into the Current Level Pointer – V0
The random sequence MHR5 is moved indirectly into the Current Level Pointer V0 and this pointer is then incremented by 1.
An initialization bit is then set.

Simon Game PLC 110-min

The initialization bit starts a timer for 600msec in order to give time for the HMI to respond. Once the time expires the Initialization bit is reset and the game start bit is set. (Y0)
Y0 – Game Started is used to determine if play is to continue.

Simon Game PLC 120-min

Play the Sequence

Simon Game PLC 130-min

Set the outputs to play the sequence.
This will also set the sound to play for each of the colours selected. (MHR2)

Simon Game PLC 140-min

Reset the sound during the playing of the sequence.

Simon Game PLC 150-min

Read the inputs from the HMI. (MC1 – MC4)
Set the bits in V501 so we can compare the word.

Simon Game PLC 160-min

If the wrong button is hit, then play a sound and stop the game.

Simon Game PLC 170-min

If the correct color is selected, increment to the next random colour in the sequence.

Simon Game PLC 180-min

If the correct colour sequence has been entered, then the level has been completed.
Start a delay to ensure that the HMI has finished playing all of the sounds.

Simon Game PLC 190-min

When the level is entered correctly and the time delay has expired, we will reset the play and input pointers. The level increases by 1 and  another random number is added to the sequence and the current level pointer is incremented by 1.
MHR1 – Level – Increases
V1 – 100
V2 – 100
V0 – New random number gets indirecly addressed and the pointer is incremented by 1

Simon Game PLC 200-min

Setting the Highest Level achieved
If the current level is greater than the highest level, the current level is moved into the highest level.

Simon Game PLC 210-min

If no key is hit for 45 seconds after the sequence is played a sound will be played and the game start bit will be reset.

Simon Game PLC 220-min

If the game start bit is off for more than 500ms, the sound will be reset.

Simon Game PLC 230-min

Download the PLC program and the Bin directory for the AdvancedHMI screen.

Watch on YouTube : Building a PLC Program that You can be Proud Of – Part 5 – Game of Simon

Part 6 will look at a sequencer controlling seven cylinders that can be taught. The cylinders can be operator programmed from the AdvancedHMI screen.

If you have any questions or need further information please contact me.
Thank you,
Garry



If you’re like most of my readers, you’re committed to learning about technology. Numbering systems used in PLC’s are not difficult to learn and understand. We will walk through the numbering systems used in PLCs. This includes Bits, Decimal, Hexadecimal, ASCII and Floating Point.

To get this free article, subscribe to my free email newsletter.


Use the information to inform other people how numbering systems work. Sign up now.

The ‘Robust Data Logging for Free’ eBook is also available as a free download. The link is included when you subscribe to ACC Automation.

PLC Programming Example – Shift Register (Conveyor Reject)

Allot of times when programming a PLC you need to track what has previously happened. Shift registers allow you to do just that. We will look at a PLC basic tutorial of a conveyor belt and reject station. Following the 5 steps to program development this PLC programming example should fully explain the function of shift registers. Ladder will be our PLC programming language.

We will be using the Do-more Designer software which comes with a simulator. This fully functional program is offered free of charge at automation direct.

Define the task:

What has to happen?
Conveyor Reject 0

A start pushbutton (NO) is used to start the conveyor and a stop pushbutton (NC) is used to stop. Sensor B detects product on the conveyor belt and sensor A will detect if it is too large and needs to be rejected. The product is tracked along the conveyor belt and when under the reject station the Reject Blow Off will expel the bad product. Product is randomly placed on the conveyor belt, so an incremental encoder is used to track the conveyor movement. The reset pushbutton (NO) will signal that all of the product on the conveyor has been removed between the sensors and reject blow off.

Define the Inputs and Outputs:

Inputs: Start Switch – On/Off (Normally Open) – NO Stop Switch – On/Off (Normally Closed) – NC Reset Switch – On/Off – NO Motor Encoder – On/Off – This will give a discrete signal when the conveyor is moving. It picks up the movement of the free wheel. Sensor A (Part Reject) – On/Off – NO Sensor B (Part Present) – On/Off – NO

Outputs: Motor – On/Off (Conveyor Run) Air Blow Off – On/Off (Reject)
Inputs_Outputs

Develop a logical sequence of operation:

Fully understanding the logic before starting to program can save you time and frustration.

Sequence Table: The following is a sequence table for our conveyor reject application.
Sequence Table

It is a simple sequence table, but clarifies the following: When power goes off and comes on the sequence will continue. This means that the shift sequencer must be memory retentive. Sensor A and B must be on to get tracked with a shift register.

Shift Registers: The Shift Register (SR) instruction shifts data through a predefined number of BIT locations. These BIT locations can be a range of BITs, a single Word or DWord, or a range of Words or DWords. The instruction has three inputs. Data, Clock and Reset. The data input will load the beginning bit with a ‘1’ if it is on or ‘0’ if it is not. Clock input is used to shift the data through the shift register. In our example, we will be using the encoder on the conveyor to track the reject container. So each pulse of the clock represents a distance on the conveyor. The last input is the reset. It will place ‘0’ in all of the bits within the shift register.
Shift Register

Develop the PLC program:

Start and stop of the conveyor motor.
Program Conveyor Reject 1

Shift register to track the rejected parts. This will move the bits with each pulse of the encoder. Note that the ‘V’ memory is used because it is memory retentive.
Program Conveyor Reject 2

This will look at the bit in front of the reject station. We can measure and count off the length (conveyor) and then find out what the bit location will be at the reject location.Program Conveyor Reject 3

Test the program:

Test the program with a simulator or actual machine. Make modifications as necessary. Remember to follow up after a time frame to see if any problems arise that need to be addressed with the program.

Conveyor Reject

Notes: Sometimes you can use multiple shift registers in your program. This can be helpful if you want to actually track the container as well as the rejects. You could also use bit shift right (BSR) and bit shift left instructions (BSR) to do the same thing as we did with the shift register instruction. In the Do-more PLC it is rotate left (ROTL) and rotate right (ROTR) instructions. Always check your instruction set of the controller that you are working with before starting to program.

Watch on YouTube : PLC Programming Example – Shift Register (Conveyor Reject)

Additional information on shift registers can be seen at the following URL:
http://accautomation.ca/plc-programming-example-sorting-station-shift-register/
This PLC programming example will look at sorting coloured tags into three different exits. The 3D simulation will use three different shift registers to trigger when to direct the correct colour tag.
Watch the sequence of operation video below.
Watch on YouTube : PLC Programming Example – Sorting Station Testing

If you have any questions or need further information please contact me.
Thank you,
Garry



If you’re like most of my readers, you’re committed to learning about technology. Numbering systems used in PLC’s are not difficult to learn and understand. We will walk through the numbering systems used in PLCs. This includes Bits, Decimal, Hexadecimal, ASCII and Floating Point.

To get this free article, subscribe to my free email newsletter.


Use the information to inform other people how numbering systems work. Sign up now.

The ‘Robust Data Logging for Free’ eBook is also available as a free download. The link is included when you subscribe to ACC Automation.