Skip to main content

How to use Lua scripts

First use

Setting Up Lua Scripting with Visual Studio Code

To make Lua scripting easier, follow these steps to set up Visual Studio Code with the Lua extension:

  1. Install Visual Studio Code

    • If you don't have it yet, download and install Visual Studio Code.

  2. Add the Lua Extension

    • Open Visual Studio Code.
    • Go to the Extensions view (click on the square icon on the sidebar or press Ctrl+Shift+X).
    • Search for "Lua" and install the Lua extension by sumneko.
      image.png

  3. Create a Folder for Libraries

    • Make a new folder on your computer to store the emdrive library. For example, you can name it D:\LuaLibraries.

  4. Configure Developer Mode and Add Library Path

    • Open Visual Studio Code.
    • Press Ctrl+P to open the search bar.
    • Type >settings and select "Open User Settings (JSON)" from the list.
      image.png


  5. Edit User Settings (JSON)

    • In the opened settings.json file, add the following code.
      "Lua.misc.parameters": [
    "--develop=true"
],
"Lua.workspace.checkThirdParty": true,
"Lua.workspace.userThirdParty": ["path_to_our_library"]
    • Make sure to keep any existing code intact. Add a comma at the end of the last line of the existing code, then paste the new code below it. Update the path to match your folder (D:/LuaLibraries). Use forward slashes instead of backslashes.

  6. Save and Close

    • Save the changes to settings.json.
    • Close Visual Studio Code.


Example of "settings.json":

image.png


Getting Started with Lua Scripting

  1. Create a New Folder

    • Make a new folder for your project.

  2. Open the Folder with Visual Studio Code

    • Right-click the folder and select "Open with Code."
      image.png
    • This will open Visual Studio Code with your new folder as the workspace.

  3. Create a New Lua Script

    • In the Explorer window of Visual Studio Code, right-click and select "New File."
      image.png
    • Name the file firstscript.lua.

Using the emdrive Library

Option 1: Automatic Setup

  1. Add Code to Script

    • In firstscript.lua, add the following line:

      require('emdrive')

  2. Apply Path Modification

    • A pop-up window will appear in the bottom right corner. Click "Apply and modify."
    • After applying, delete the require('emdrive') line.
      image.png

  3. Check .vscode Folder

    • A new folder named .vscode will be created.
    • Inside, there will be a settings.json file containing the path to the library.

Option 2: Manual Setup

  1. Create .vscode Folder

    • Manually create a .vscode folder in your workspace.

  2. Create settings.json File

    • Inside the .vscode folder, create a settings.json file.

  3. Add Library Path to settings.json

    • Add the following code to settings.json: 


      {
    "lua.workspace.library": [
        "D:/LuaLibraries"
    ]
}

Examples

Example 1: "Hello World"

Description:

Print "Hello World" every 100ms to IO_Output.

ForTo make the script to workwork, you need to have 2two functionsfunctions: "Initialite"Initialize and "Loop"Loop.

  1. Copy the Code

    Copy the following code to an example.lua file.file:

    function Initialize()	
	LoopPeriodMs = 100
end

function Loop()
    IO.Write("Hello World ")
end

  2. To loadLoad the scriptScript on the inverterInverter

    you
      need
    • Go to go into 0x2040 0x05 - Script,.
      • where
    • Select you select write"Write from filefile" and then click "...".
    • A pop pop-up window appearswill whereappear. you then locatedLocate the saved script and click "Open",.
      • after
    • Click that you click write."Write".


  3. IfCheck if the scriptScript is correctlyValid

    written
      you
    • Go can se under objectto 0x2040 0x02 - Status.
      • the
    • The value "3" - Which means thatindicates the downloaded file is valid.
      • To
    run

  4. Run the scriptScript

    you
      need to set object
    • Set 0x2040 0x03 - Control =to 2.
      • You can see in status if
    • If the script is runningrunning, the status value should be "5".

      • To
    se

  5. View the theOutput

    "Hello
      World" you need
    • Go to go to object 0x2040 0x07 - IO_output,.
      • where
    • Click you"Read" canto click read andsee the "Hello World" string will appear in the Description window.


Example 2: Data types & variables

Example 2.1: Data types

Lua is a lightweight, high-level programming language known for its simplicity and flexibility. It has several basic data types, each serving a different purpose. Here are the main data types in Lua along with examples for each:

  1. Nil
    Represents the absence of a value.
  2. Boolean
    Represents a boolean value, either true or false.
  3. Number
    Represents both integer and floating-point numbers.
  4. String
    Represents a sequence of characters.
  5. Table
    Represents associative arrays, which can be used as arrays, dictionaries, or other data structures.
  6. Function
    Represents a callable function.
function Initialize()	
	LoopPeriodMs = 100
end

function Loop()
    
    -- 1. Nil
    local myVariable = nil
    IO.Print(myVariable)  -- Output: nil

    -- 2. Boolean
    local isTrue = true
    local isFalse = false
    IO.Print(isTrue)  -- Output: true
    IO.Print(isFalse)  -- Output: false

    -- 3. Number
    local integerNumber = 42
    local floatingNumber = 3.14
    IO.Print(integerNumber)  -- Output: 42
    IO.Print(floatingNumber)  -- Output: 3.14

    -- 4. String
    local myString = "Hello, Lua!"
    IO.Print(myString)  -- Output: Hello, Lua!

    -- 5. Table
    local myTable = { key1 = "value1", key2 = "value2" }
    IO.Print(myTable.key1)  -- Output: value1
    IO.Print(myTable.key2)  -- Output: value2

    local arrayTable = { "apple", "banana", "cherry" }
    IO.Print(arrayTable[1])  -- Output: apple

    -- 6. Function
    local function myFunction(a, b)
      return a + b
    end
    IO.Print(myFunction(2, 3))  -- Output: 5
 
    -- 6. Anonymous function
    local anonFunction = function(x, y)
      return x * y
    end
    IO.Print(anonFunction(4, 5))  -- Output: 20

end

Example 2.2: Variables

  1. Global variables
    Global variables are accessible from anywhere in the program unless shadowed by a local variable of the same name. By default, any variable declared without the local keyword is global.
    myGlobalVariable = 10  -- Global variable

function printGlobal()
  print(myGlobalVariable)
end

printGlobal()  -- Output: 10
  2. Local Variables
    Local variables are only accessible within the block or function where they are declared. They help avoid polluting the global namespace and can be used to manage scope more effectively.
    local myLocalVariable = 20  -- Local variable

function printLocal()
  local myLocalVariable = 30  -- Local to this function
  print(myLocalVariable)
end

printLocal()  -- Output: 30
print(myLocalVariable)  -- Output: 20
  3. Table fields
    Variables can also be fields of tables, allowing for the creation of more complex data structures like arrays, dictionaries, and objects.
    local myTable = {
  field1 = "Hello",
  field2 = "World"
}

print(myTable.field1)  -- Output: Hello
print(myTable.field2)  -- Output: World

Variable scope

  • Global Scope: Variables declared outside of any function or block are global by default.
  • Local Scope: Variables declared with the local keyword within a function, block, or loop are local to that block.
  1. Global vs. Local
    myGlobal = "I am global"

function testScope()
  local myLocal = "I am local"
  print(myGlobal)  -- Accessible
  print(myLocal)   -- Accessible
end

testScope()

print(myGlobal)  -- Accessible
-- print(myLocal) -- Error: myLocal is not accessible here

  2. Local Variable Shadowing
    local x = 5  -- Local variable in the main chunk

function shadowTest()
  local x = 10  -- Local variable in the function
  print(x)  -- Output: 10
end

shadowTest()
print(x)  -- Output: 5

Global variables and tables use a lot of memory, especially in embedded systems. To save memory, it's best to use local variables whenever possible. 
If you use a global variable at the start of your code and don't need it later, clear the global variable to free up memory. You can do this by adding the following code:

myGlobalVariable = nil

 

Example 3: Inputs/Outputs

Example 3.1: Use of digital inputs & outputs

Turn low side 1 - ON when switch on digital pin 1 is switched ON.

function Initialize()	
	LoopPeriodMs = 10
end

function Loop()

    local switch = Digital.Get(DIGITAL_IN_1)

    if switch == 1.0 then
        Digital.Set(LOW_SIDE_1, 1)
    else
        Digital.Set(LOW_SIDE_1, 0)
    end
end

Example 3.2: Use of analog inputs

Print analog value of analog input 1 when switch on digital pin 1 is switched ON.

function Initialize()	
	LoopPeriodMs = 10
end

function Loop()

    local switch = Digital.Get(DIGITAL_IN_1)

    if switch == 1.0 then
        local rawVal = Analog.Get(ANALOG_IN_1)
        IO.Print(rawVal)    
    end
end

Loop period is set to 1000ms
LED is connected on low side 1.
Blink LED every 0.5s with Time.WaitMs().

function Initialize()	
	LoopPeriodMs = 1000
end

function Loop()

    local ledState = Digital.Get(LOW_SIDE_1)

    if(ledState == 0.0) then
        Digital.Set(LOW_SIDE_1, 1.0)
    else
        Digital.Set(LOW_SIDE_1, 0.0)
    end

    Time.WaitMs(500)

end

NowIf we set the LoopPeriodMs =to 100
We see that100ms, the script doesstops notrunning runand anymore,shows we get undera status the numberof "6", which meansmeaning "Script timed out and was stopped".stopped."


With

Here are the functionkey points to understand:

  • Time.WaitMs(), weFunction: waitThis infunction pauses the codescript for thea specified timetime. (inIn thisour exampleexample, 0,5s).it Butpauses wefor specified0.5 thatseconds.
  • LoopPeriodMs Setting: We set the script to loop every 100ms.
  • Error Explanation: Since the script must loop throughevery under100ms 100ms,but andpauses thusfor we0.5 getseconds, it causes an error.
    • Using
tthe

Important functionNote: Be very careful when using the Time.WaitMs() we havefunction to beavoid verysuch careful.errors.

We want the LED to blink the LED every 0.5s5 butseconds, still want to havewhile the main loop to be executedruns every 10ms. WeHere's achivehow thiswe withdo theit:

following
code:

  1. Count Loops: We count everyeach loop from 1 to 5050.
    2. and
  2. Multiply multiplyCounter: Multiply the counter withby the loop period.period Then(10ms).
    3. we
  3. Check divideReminder: Divide the numberresult withby 500500.
    4. and
  4. Toggle ifOutput: If the reminderremainder is equal to 0 than0, we toggle the output.

    LED.
Main_loop_period = 10
Counter = 1


function Initialize()	
	LoopPeriodMs = Main_loop_period
end

function Loop()

    if ((Counter)*Main_loop_period)%500==0 then
    
        local ledState = Digital.Get(LOW_SIDE_1)

        if(ledState == 0.0) then
            Digital.Set(LOW_SIDE_1, 1.0)
        else
            Digital.Set(LOW_SIDE_1, 0.0)
        end

    end
 
    if Counter<50 then
        Counter=Counter+1
    else
        Counter=1
    end

end


The script initializes a start time variable and defines two functions. In the Loop function, the script checks if the StartTime is nil and if so, sets it to the current time in milliseconds.
The Loop function then continuously gets the current time in milliseconds. If 500 milliseconds have passed since the StartTime, it resets the StartTime to the current time.
It then gets the state of a digital output LOW_SIDE_1.
If LOW_SIDE_1 is off (state is 0.0), it turns it on by setting its (state to 1.0.0).
If LOW_SIDE_1 is on (state is not 0.1.0), it turns it off by setting its (state to 0.0.0).

This process repeats every 500 milliseconds, toggling the state of LOW_SIDE_1 each time.

StartTime = nil

function Initialize()	
	LoopPeriodMs = 10
end

function Loop()

    --Execute only once at the start of the loop
    if(StartTime == nil) then
        StartTime = Time.GetMs()
    end

    --Chechk every loop what is the time
    local CurrentTime = Time.GetMs() 

    if (CurrentTime - StartTime >= 500) then
        StartTime = CurrentTime

        local ledState = Digital.Get(LOW_SIDE_1)

        if(ledState == 0.0) then
            Digital.Set(LOW_SIDE_1, 1.0)
        else
            Digital.Set(LOW_SIDE_1, 0.0)
        end

    end
end

Example 5: CAN send

Example 5.1: (CAN send simple message)

We want toTo send a simple CAN message frame from lua script every 100ms with an ID =of 0x205 and data value 500 using the first 2 bytes.bytes, follow these steps: 

image.png


For

this
    we
  1. can

    Use useTemplate:

    the
    • Start with example 4.3 as a template.
      • We
    need
    2. to
  2. add

    Add Variables and Functions:

    • Define a CanID variable,variable.
    • Initialize CAN with the CAN.Initialite(Initialize() function.
      • For
    sending
    3. we
  3. only

    Sending needParameters:

    • Use the paramaterCAN_TX_ONLY CAN_TX_ONLY,parameter messagesfor sending.
    • Messages will not be extendedextended.
      • and
    • Set filters to 0 since we are only sending.

  4. Modify the filtersCode:

    can
      also be 0, because as mentioned we will only send.
      When that is finished we delete
    • Delete the code for toggling the outputoutput.
      • and
    create

  5. Create Custom Function:

    • Create a custom function whichthat will beis called every 100ms.
      The
      • function
    • Name takes in onethe argument whichData_raw.
      • will
    • Split be called Data_raw, that data is then splitData_raw into 2 bytesbytes.
      • and sent via
    • Send the data using the CAN.Send() function.

CanID = 0x205

StartTime = nil

function Initialize()

    CAN.Initialize(CAN_TX_ONLY,false,0,0)

	LoopPeriodMs = 10
end

function Loop()

    --Execute only once at the start of the loop
    if(StartTime == nil) then
        StartTime = Time.GetMs()
    end

    --Chechk every loop what is the time
    local CurrentTime = Time.GetMs() 

    if (CurrentTime - StartTime >= 100) then
        StartTime = CurrentTime
        SendData(500)
    end
end

function SendData(Data_raw)
    local val = Data_raw
    local byte0 = math.floor(val) & 0xFF
    local byte1 = (math.floor(val) & 0xFF00) >> 8
    CAN.Send(CanID,{byte0,byte1,0,0,0,0,0,0})
end

Example 5.2 : CAN send extended message (J1939)

We will do the same as in example 5.1 except we will send an extended message (It will be a J1939 message PH3 - the data order might be different)different in the standard).

 
ID = 0x18FF8203. 

The only thing we need to change is 2 lines, we need to change the CanID and in the CAN.Initialize() functionfunction, the boolean value to true. If we change only the CanID then the message will still be sent out but instead withthe ID 0x18FF8199 it will be 0x199 (the last 3 digits willof be- theID ID)0x18FF8199).

CanID = 0x18FF8199
CAN.Initialize(CAN_TX_ONLY,true,0,0)

Example 6: CAN receive

Example 6.1 : CAN receive

In this example we will turn ON and OFF a LED that is connected on low side 1.1 with a received can message.
The Can ID has to be 0x123 and we will send only one byte of data. If the value of data is 1 then the LED will be turned ON, otherwise it will be turned OFF. 
 
To use the CAN receive function we need to change the CAN.Initialite() and add a function called "CAN.Received(message) end"". With the following code we always go into the CAN.Received() function when a message is received and then we check if the ID is correct.

function Initialize()
    CAN.Initialize(CAN_RX_TX,false,0,0)
	LoopPeriodMs = 10
end

function Loop()


end

function CAN.Received(message)
    if (message.ID == 0x123) then
        IO.Print(" Data1: ", message.Data[1])
        if(message.Data[1] == 1) then
            Digital.Set(LOW_SIDE_1, 1.0)
        else
            Digital.Set(LOW_SIDE_1, 0.0)
        end
    end
end


We can also add a filter so we only go into the CAN.Received() when the message has a proper ID. We achieve this with the following code.

function Initialize()
    CAN.Initialize(CAN_RX_TX,false,0x123,0x123)
	LoopPeriodMs = 10
end

function Loop()


end

function CAN.Received(message)
    --if (message.ID == 0x123) then
    IO.Print(" Data1: ", message.Data[1])
    if(message.Data[1] == 1) then
        Digital.Set(LOW_SIDE_1, 1.0)
    else
        Digital.Set(LOW_SIDE_1, 0.0)
    end
    --end
end

Example 7: Read & Set CANopen objects

Within a lua script you can read and modify CANopen objects, just like with the configurator tool.
In this exampleexample, we willwe'll use an analog input (HW AIN1AIN1) )as a throttle andto set the motor velocity reference (object 0x3010 0x05 - VelocityRef object.). We will also read the samethis object and print itits value to the luaLua output. WeAdditionally, will alsowe'll limit the maxmaximum RPM insideusing lua withthe math library,library to prevent the motor from running away if there's a problem with the analog reading appears the motor wont run away.reading.

0V = 0RPM
5V = 200RPM

For this example to work you need an inverter that is configured to work with the connected motor. You need to be first able to spin it in velocity mode using the configurator.
When you start the script go to operational and turn on PWMs manually.

If the analog throttle is damaged (either a short circuit or a broken circuit), there is no safety implemented.system in place. Here’s what can happen:

If therethe circuit is a breakbroken, no voltage will be appliedapplied, and the RPM =will be 0. But if
If there is a short thancircuit, the inverter will getreceive the full 5V on the analog inputinput, causing the RPM =to MAX.go Thisto isthe whymaximum.

To prevent these issues, we need to implement someadd safety featuresfeatures. (These will be showndemonstrated in exampleExample 8). 8.

VelocityRef = {0x3010, 0x05}

function Initialize()
	LoopPeriodMs = 10
end

function Loop()
   

    local rpm = Analog.Get(ANALOG_IN_1) * 40
    rpm = math.min(rpm,200)

    CANopen.SetObjectValue(VelocityRef, rpm)
    
    local VelRef_from_CANopen = CANopen.GetObjectValue(VelocityRef)

    IO.Print(VelRef_from_CANopen)
end

Example 8: Demo application

Example 8.1 : Demo application using CANopen objects.

WeIn this example, we will demonstrate how to use the HW AIN1 input for a simple throttle inputcontrol -with potenciometera potentiometer (0-5V.5V).


Min
    RPM
  • Throttle =Input: HW AIN1 (0-5V Potentiometer)
    • Minimum RPM: 0 =(corresponds to 0.5V
      Max5V)
      • RPM
    • Maximum =RPM: 200 =(corresponds to 4.5V
      5V)
    • Motor Stop Conditions:
      • If the throttle voltage is bellowbelow 0.2V andor above 4.8V we stop8V, the motor (will stop to protect against short and break protection).
        issues.
    • PWM Enable Condition:
      • If the throttle voltage is bellowbelow 0.5 we enable5V, the PWMs

        PWM signals will be enabled
function Initialize()

    CANopen.SetObjectValue(VelocityRef, 0) -- Set Velocity ref to 0
	CANopen.SetObjectValue(ControlMode, 1) -- Set velocity mode
	CANopen.SetNMTState(CO_OPERATIONAL)    -- Go into operational mode

	LoopPeriodMs = 100
end

function Loop()
    local throttleVoltage = Analog.Get(ANALOG_IN_1)
    -- Decide whether to enable or disable the motor
    if Digital.Get(DIGITAL_IN_1) == 1 then
        -- only enable if voltage on analog in 1 is < 0.5 V so the motor does not start ang goes to high RPM
        if (throttleVoltage < 0.5) then
            CANopen.SetObjectValue(PwmControl, 1)
        end
    else
        CANopen.SetObjectValue(PwmControl, 0)
    end

    if (throttleVoltage > 0.2 and throttleVoltage < 4.8) == true then
           -- Map values 0.5 - 4.5 V to 0 - 200 RPM and
            local rpm = (throttleVoltage - 0.5) / 4 * 200
            rpm = math.min(rpm, 200)
            rpm = math.max(rpm, 0)
            CANopen.SetObjectValue(VelocityRef, rpm)
    else
        CANopen.SetObjectValue(VelocityRef, 0)
        CANopen.SetObjectValue(PwmControl, 0)
    end
end

Example 8.2 : Demo application using dedicated motor library.

MinIn RPMthis = 0 = 0.5V
Max RPM = 200 = 4.5V
If throttle voltage is bellow 0.2V and above 4.8Vexample we stopwill have the motorsame (shortfunctionality and break protection).
If voltage is bellow 0.5 we enableof the PWMs.
code as in example 8.1. but with the use of motor library
With the use of the motor library the code is easier to read and write than example 8.1.

function Initialize()

    Motor.SetReferenceVelocity(0)       -- Set Velocity ref to 0
	Motor.SetControlMode(VELOCITY_MODE) -- Set velocity mode
	CANopen.SetNMTState(CO_OPERATIONAL) -- Go into operational mode

	LoopPeriodMs = 100
end

function Loop()
    local throttleVoltage = Analog.Get(ANALOG_IN_1)
    -- Decide whether to enable or disable the motor
    if Digital.Get(DIGITAL_IN_1) == 1 then
        -- only enable if voltage on analog in 1 is < 0.5 V so the motor does not start ang goes to high RPM
        if (throttleVoltage < 0.5) then
            Motor.Enable()
        end
    else
        Motor.Disable()
    end

    if (throttleVoltage > 0.2 and throttleVoltage < 4.8) == true then
           -- Map values 0.5 - 4.5 V to 0 - 200 RPM and
            local rpm = (throttleVoltage - 0.5) / 4 * 200
            rpm = math.min(rpm, 200)
            rpm = math.max(rpm, 0)
            Motor.SetReferenceVelocity(rpm)
    else
        Motor.SetReferenceVelocity(0)
        Motor.Disable()
    end
end

Example 9: Throttle script (state - machine)

We

Throttle willControl

control
  • Adjusting the throttleThrottle: usingUse athe potentiometer onconnected Analog_IN_1,to whichAnalog_IN_1.
    • will
  • Protection: haveThe potentiometer is protected against short and break circuitcircuits.
    • protection
  • Deadband: implemented. We will also have aA deadband of 0.3V.3V Theis minimumset speedfor shallthe bepotentiometer.
  • Speed Limits:
    • Minimum speed: 0 RPM
      • and
    • Maximum the maxspeed: 300 RPM
      • (limits).

Motor Operation

  • Activation:
    • The motor willruns only spin if thewhen digital pin 1 (ON/OFF switch) is connectedconnected.
      • - we will have a switch ON/OFF.
      The
    • Change motor direction can be changed withusing a switch on digital pin 3.

      • The

    actual
    • rpm
  • Speed isSetting: set
      through
    • Forward max speed: Object 0x3020 0x0D
    • Reverse max speed: Object 0x3020 0x0E
    • Switching direction at max speed changes to the objectscorresponding 0x3020reverse 0x0Dspeed.

LED Diagnostics

  • LED Indicator (HS1):
    • On: System working normally.
    • Blinking: System in error mode.
  • Error Blink Codes:
    • Error 2: Blinks twice, then pauses.
    • Error 3: Blinks three times, then pauses.

Voltage and RPM Details

  • Working Voltage Range:
    • Minimum RPM: at 0.5V
    • Maximum RPM: at 4.5V
    • Deadband: 0.3V
  • Error Conditions:
    • ERROR1: Voltage out of bounds
    • ERROR2: Analog_IN_1 < (Min_Volt - Forward_max_speedDeadband)
      • and
    • ERROR3: 0x3020Analog_IN_1 0x0E> -(Max_Volt Reverse_max_speed.

      + Deadband)

CANopen Error Messages

  • Error Message (0x80 + nodeID):
    • Sent every 100ms in error state.
    • Data length: 8 bytes.
    • Byte 0 Mapping:
      • Bit 0: Throttle potentiometer error out of bounds
      • Bit 1: Throttle potentiometer break circuit error
      • Bit 2: Throttle potentiometer short circuit error
  • Warning Message (0x180 + nodeID):
    • Sent every 100ms in start state.
    • Data length: 8 bytes.
    • Byte 0: Warning code 0x01 (Motor disabled, potentiometer not in min position)

If the motor spins at Forward max speed and you switch the direction with the switch then it will spin at Reverse max speed

There will be LED light connected to HS1 which will be for diagnostic. When the system is working it will be turned on. If the system is in error mode it will blink.
ERRO2 = blink 2 times then pause
ERRO3 = blink 3 times then pause

Working voltage range
Min_RPM = 0, at Min_Volt = 0.5V
Max_RPM = 200, as Max_Volt = 4.5V

DeadBand = 0.3V

This means that if voltage goes (bellow Min_RPM - DeadBand)
ERROR1 => Out of bounds
ERROR2 => Analog_In_1 < Min_Volt- DeadBand
ERROR3 => Max_Volt + DeadBand < Analog_In_2

The application will send a standard CANopen error message on 0x80 + nodeID every 100ms while in error state. There will also be TPDO message on 0x180 + nodeID which will send out the warrning code every 100ms while in start state.

0x80 + nodeID message will have a data length of 8 bytes. And the mapping is as follows:
byte0:
bit0 = Throttle potentiometer error
bit1 = Throttle potentiometer break circuit error
bit2 = Throttle potentiometer short circuit error

0x180 9 nodeID message will have a length of 8 bytes. And the mapping is as follows:
byte0: warning code

Warning code:
0x01 Motor is disabled, due to potentiometer not in min position

--[[ @file Example_9
@brief User manual examples
@author Matic Jehart
@date 05.07.2024
@version V1.0.0
]]Limits
MAX_RPM = 300
MIN_RPM = -300

-- Objects
FORWARD_MAX_SPEED_ID = {0x3020, 0xD}
REVERSE_MAX_SPEED_ID = {0x3020, 0xE}
LED_ID 				 = {0x30A4, 0x02}


-- Inputs
ENABLE_SW 	 = DIGITAL_IN_1
DIRECTION_SW = DIGITAL_IN_2
THROTTLE_IN  = ANALOG_IN_1
DIRECTION_IN = DIGITAL_IN_3


-- Voltage thresholds
THROTTLE_MIN_V = 0.5
THROTTLE_MAX_V = 4.5
DEADBAND 	 = 0.3


ERROR	  = 0
ERROR_reg = 0
WARNINGS  = 0


StartTime1	= nil
StartTIme2	= nil
StartTime3 	= nil
StartTime4 	= nil
FlagCounter = 0


DIN		  = {ON = 1, OFF = 0}
LED 	  = {OFF = 0x0, ON = 0x1}
DIRECTION = {FORWARD = 1, REVERSE = 0}

-- Application FSM
Application = {}


function Initialize()
	CAN.Initialize(CAN_TX_ONLY,false,0,0)

	Application.NextState = "Idle"

    Motor.SetReferenceVelocity(0)
	Motor.SetControlMode(VELOCITY_MODE)

	LoopPeriodMs = 10
end


function Loop()
	Application[Application.NextState]()
end


Application.Idle = function ()
	local ledValue = CANopen.GetObjectValue(LED_ID)

	if ledValue == 1 then
		CANopen.SetObjectValue(LED_ID, 0)
	endLED.ON)
	CANopen.SetNMTState(CO_OPERATIONAL)
	Application.NextState = "Start"
end


Application.Start = function ()


    -- IF enable switch is off go to stop state
    if (Digital.Get(ENABLE_SW) == DIN.OFF ) then
		Application.NextState = "Stop"
		return
	end


    -- Get voltage
	local throttleVoltage = Analog.Get(THROTTLE_IN)


    -- Go into error state if throttle voltage is out of bounds
    if OutOfBounds(throttleVoltage, (THROTTLE_MIN_V - DEADBAND), (THROTTLE_MAX_V + DEADBAND)) == true then
		ERROR = (ERROR or 0) | 1
		Application.NextState = "Error"
		return
	end


    -- Check that voltage is bellow minimal throttle voltage - so that the motor does not start at high speed
	if Motor.GetState() == MOTOR_OFF then
		if throttleVoltage < (THROTTLE_MIN_V) then
            Motor.Enable()
			WARNINGS = WARNINGS & Negate_Xbit(1, 8)
            return
		else
			WARNINGS = (WARNINGS or 0) | 1
        end
	end

	-- Only set velocity reference when pwms are enabled
	if ((Motor.GetState() == MOTOR_RUN) and (throttleVoltage >= 0.5)) then
		-- Calculate Voltage
    	--local rpm = ((throttleVoltage - THROTTLE_MIN_V) * MAX_RPM) / (THROTTLE_MAX_V - THROTTLE_MIN_V)
		local rpm = ((throttleVoltage - THROTTLE_MIN_V) * GetMaxSpeed()) / (THROTTLE_MAX_V - THROTTLE_MIN_V)
    	-- Limit RPM
    	rpm = math.min(rpm, MAX_RPM)
    	rpm = math.max(rpm, MIN_RPM)
		IO.Print("REF: ", rpm)
    	-- Set ref
		Motor.SetReferenceVelocity(rpm)
	end

	-- Send warnings every 100ms
	local CurrentTime = Time.GetMs()
	if((StartTIme2 == nil) or (CurrentTime-StartTIme2) >= 100) then
		SendWarnings()
	end
end


Application.Stop = function ()
	Motor.Disable()
    --When eneble sw is activated go to start state
	if (Digital.Get(ENABLE_SW) == DIN.ON) then
		Application.NextState = "Start"
	end
end

Application.Error = function ()

    Motor.Disable()
	Motor.SetReferenceVelocity(0)

	--local ledValue = CANopen.GetObjectValue(LED_ID)
    local throttleVoltage = Analog.Get(THROTTLE_IN)
	local ErrorBlinkCounter = 0
	local CurrentTime

	--If bit 0 = 1 thanthen OutOf BoundsOutOfBounds is detected
	if (ERROR & 1) == 1 then
		if throttleVoltage < (THROTTLE_MIN_V - DEADBAND) then
			ERROR = ERROR | 2
			ERROR_reg = ERROR_reg | 1 -- set the generic error register
		elseif throttleVoltage > (THROTTLE_MAX_V + DEADBAND) then
			ERROR = ERROR | 4
			ERROR_reg = ERROR_reg | 1 -- set the generic error register
		else
			-- Clear ERROR bit 0, 1, 2
			ERROR = ERROR & Negate_Xbit(7, 16)
			-- Clear the generic error register
			ERROR_reg = ERROR_reg | Negate_Xbit(1, 8)
		end
	end

	-- Send Errors every 100ms
	CurrentTime = Time.GetMs()
	if ((StartTime1 == nil) or (CurrentTime - StartTime1) >= 100) then
		StartTime1 = CurrentTime
		SendError()
	end

	-- Determine the how many times we want to blink the led
    if ((ERROR & 2) >> 1) == 1 then
        ErrorBlinkCounter = 2
    elseif ((ERROR & 4) >> 2) == 1 then
        ErrorBlinkCounter = 3
    end

    -- Start the blinking cycle if enough time has passed
	CurrentTime = Time.GetMs()
    if StartTime3 == nil or (CurrentTime - StartTime3) >= 3000 then
        StartTime3 = CurrentTime
        FlagCounter = 0
    end

    -- Handle the blinking logic
    if FlagCounter < 2 * ErrorBlinkCounter then
        if StartTime4 == nil or (CurrentTime - StartTime4) >= 200300 then
            StartTime4 = CurrentTime
            FlagCounter = FlagCounter + 1

            -- Toggle LED
            --if ledValue == 0  then
            if FlagCounter % 2 == 1 then
				CANopen.SetObjectValue(LED_ID, LED.ON)
            else
                CANopen.SetObjectValue(LED_ID, LED.OFF)
            end
        end
	else
		-- Ensure the LED is off during the pause period
        CANopen.SetObjectValue(LED_ID, LED.OFF)
    end

    if ERROR == 0 then
		FlagCounter = 0
		CANopen.SetObjectValue(LED_ID, LED.OFF)
		Application.NextState = "Idle"
		return
	end
end


function GetMaxSpeed()
	if Digital.Get(DIRECTION_IN) == DIRECTION.FORWARD then
		return CANopen.GetObjectValue(FORWARD_MAX_SPEED_ID)
	end
	return CANopen.GetObjectValue(REVERSE_MAX_SPEED_ID)
end


function SendError()
	-- Send on ID + nodeID; we get the NodeId from CANopen off the inverter
	local CanID = 0x80 + CANopen.GetObjectValue({0x100B, 0x00})
	local byte0 = ERROR & 0xFF
	local byte1 = (ERROR & 0xFF00) >> 8
	local byte2 = ERROR_reg & 0xFF
	CAN.Send(CanID,{byte0, byte1, byte2, 0, 0, 0, 0, 0})
end

function SendWarnings()
	-- Send on PDO + nodeID;
	local CanID = 0x180 + CANopen.GetObjectValue({0x100B, 0x00})
	local byte0 = WARNINGS & 0xFF
	CAN.Send(CanID,{byte0, 0, 0, 0, 0, 0, 0, 0})
end


function OutOfBounds(throttleVoltage, minVal, maxVal)
    if (throttleVoltage < minVal) or (throttleVoltage > maxVal) then
        return true
    else
        return false
    end
end


--- Fuctino to negate bits
---@param value number Value to negate
---@param xBit number Number of bites e.g 16bit => xBit = 16
function Negate_Xbit(value, xBit)
    local negated = 0
    for i = 0, (xBit - 1) do
        if (value & (1 << i)) == 0 then
            negated = negated + (1 << i)
        end
    end
    return negated
end

Error 0x06070010 when loading a script may indicate Lua object 0x2040 0x01 isn't set to 1. To resolve, ensure proper access level in Configurator to unlock this feature. If you do not have the proper access level contact us.

image.png

image.png


Best practices

For further insights and practical tips, I recommend exploring "Programming in Lua," available at: Programming in Lua. Authored by experts in the field, this comprehensive resource offers invaluable guidance for Lua developers. It's worth noting that the entire topic is accessible free of charge as of April 24, 2024. Additionally, some sections of the topic include examples to further illustrate key concepts and techniques.

Minimizing Global Variables

In Lua scripting, it's imperative to exercise caution with global variables to prevent memory exhaustion and script failures, especially on embbeded systems. Emphasizing the utilization of local variables whenever possible is paramount. By minimizing global variable usage, we mitigate the risk of memory overflow and enhance script performance.

Example:

myGlobalVaribale = 10  --Global variable
local myLocalVaribale = 10  --Local variable

Issues

If IO.Print() isn't functioning, it may signal an outdated firmware version. Firmware 0x10C01 lacks support, while 0x10D02 enables the function.


Back to top