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DE-4000 SCRIPTING REFERENCE MANUAL

There is a delicate balance between providing a system that has capabilities that can be configured through a fixed set of options, and one that can be extended and expanded with custom programming. In designing the DE-4000 control system, the choice was made to provide a system where most applications can be met with simple configuration, but advanced functionality can be provided through custom programming using the “Lua” language.

Lua is often referred to as a scripting language. Scripting languages differ from compiled languages as they eliminate extra step of compiling the written program into machine code.

Lua comes with a background of being robust, fast, and geared towards embedded applications, with a proven track record in the gaming industry. For the DE-4000 system it is small and fits in the memory we have available, holds a lot of power, and keeps it simple for writing in the language. All information regarding the Lua scripting language is located at https://Lua.org Using the Lua engine as an embedded tool allows for taking advantage of a full architecture and standard at your fingertips. Within the language there are all of the normal attributes to programming such as functions, variables, statements, expressions etc. All of this reference material can be found at https://lua.org/ manual/5.3/ For getting started and using a guided reference, there are several editions of “Programming in Lua” available. Most recent editions are a paid for product that come in paper back or ebook form. While testing out Lua and becoming familiar, a free first edition is available and covers a lot of learning needs to get comfortable with the language. It can be located at https://www.lua.org/pil/contents.html. A major advantage to using Lua is its inherent ability to allow custom functions. While all normal functions and calls are published, there is the ability to add new functions in the DE-4000 firmware. Once new functions are defined and have calls to their internal properties, they then can be published for the user. This includes functions such as our flexible Modbus table and talking with various terminal boards linked in the system. Below is the start to the list of Altronic based functions. As functionality and features come to life through new ideas, this document will continually get updated with the latest scripts that we make available.

GETTING STARTED WITH DE-4000 SCRIPTS Basic Scripting on DE-4000

 

Begin on Dashboard on DE-4000 system environment

Choose “Global” from menu on left side of screen

In the Sub-Menu on the Left side select “Scripts”

Select one of the page icons under one of the 4 script options to open editor

Scripting can be entered into the editor

Scripting Windows and examples

Master Script

The Master Script section is the Primary scripting environment. Primary scripting functions can be written in this section.

Example:

local suction = get_channel_val(1,1)
local discharge1 = get_channel_val(1,3)
diff = discharge1 - suction
set_sVirt(“Difference”, diff)

The first line gets the channel value from Terminal board 1 Input 1 and stores it in local variable named suction. The second line gets the channel value from Terminal board 1 Input 3 and stores it in local variable named discharge1. The third line takes the discharge1 pressure and subtracts the suction pressure and stores it in the global variable named diff (NOTE: Any value that you want to access from another scripting section must be stored in a global variable. This is used most in calling values into Modbus registers as explained below). The fourth line copies the value from diff and stores it into the Virtual status channel named “Difference” This channel can be displayed on the Dashboard.

Control Script

The Control Script section is used to override the default control strategy found on the Global/Control page. A copy of the default control script (found in attached appendix) can be copied into this section and then modified to change the control functionality as well as add additional control loops beyond the default 2.

Modbus Script

The Modbus Script section is used to move data into and out of Modbus registers

defaultModbus()
set_modbus(300,diff)

The first line pulls in the factory set Modbus mapping The second line moves the value from the global variable named diff into the 40300 Modbus Register

DE-4000 Lua Script API

CUSTOM FUNCTIONS FOR SCRIPTING

create_param(“index”,default,”catergory”,”description”)
  • creates a user configurable parameter
  • parameter is stored as index,
  • default value(If not changed by user) is default
  • parameters will be grouped on the Global/Params page by category
  • description is text to describe the parameter to the user

Example:

create_param("NumEngCyl",8,"Engine Params","Num. of Engine Cylinders")
get_channel_val(terminal,channel)
  • returns current value of analog input channel on terminal module terminal
  • return value type is numeric

Example:

local sp = get_channel_val(1,5)
 reads value of Suction Pressure from Terminal Module #1 , Input #5
get_gbl(“index”,default)

  • returns global config setting stored under index or returns default if not defined

    note: get_gbl is used to retrieve global CONFIGURATION settings that are typically set when the system is configured and do not change as the system is running. If you want to set and retrieve global STATUS variables use the get_sGbl() and set_sGbl() functions >If you want to create and read virtual channels use the set_sVirt() and get_sVirt() functions.

Example:

local nt = get_gbl("NumTerm",1)

gets the number of terminal boards installed in the system

get_param(“index”)
  • return either the default value or the user configured value of the parameter index

Example:

get_param("NumEngCyl")

>gets the configured parameter for number of engine cylinders

get_rpm(channel)
  • reads the RPM input channel in units of revolutions per minute

note: valid channel numbers are 1 – 10(2 channels per board, up to 5 terminal boards)

Each Terminal Module has 2 RPM inputs (RPM1 and RPM2)

  • Terminal Module #1 RPM channels are 1,2
  • Terminal Module #2 RPM channels are 3,4
  • Terminal Module #3 RPM channels are 5,6
  • Terminal Module #4 RPM channels are 7,8
  • Terminal Module #5 RPM channels are 9,10

Example:

local engineRPM = get_rpm(1)
local turboRPM = get_rpm(6)

Read RPM1 channel from terminal module #1 and read RPM2 channel from Terminal module #3

get_sGbl(“index”, default)
  • If index is defined in the global status table then it returns the value associated with index
  • If index is not defined and optional default is provided then returns default

>note: It is recommended to always provide a default value when using this function

Example:

local cp = get_sGbl("calculatedPressure",0)

get the previously stored value “calculatedPressure”, Returns 0 if not found.

get_state()
  • returns the current engine state(possible values currently 0 – 10)

Example:

local engineState = get_state()
if engineState > 7 then
    set_timer("WarmupTimer",1000)
end
get_sVirt(“index”)
  • returns the value of virtual channel index or returns default if the virtual channel does not exist.

Example:

local tl = get_sGbl("timeLimit")
local et = get_sVirt("ElapsedTime",0)
if et > tl then
    set_sGbl("timeExceeded",true)
else
    set_sGbl("timeExceeded",false)
end

Gets the value of virtual channel ElapsedTime and set value of status global “timeExceeded” if ElapsedTime is greater than status global “timeLimit”

get_time()
  • returns the UNIX “epoch” time (Defined as the number of seconds elapsed since Jan 1, 1970)

Example:

local startTime = get_sGbl("startTime",0)
if startTime == 0 then
    local currentTime = get_time()
    startTime = currentTime
    set_sGbl("startTime",currentTime)
end
local et = get_time() - startTime
set_sVirt("ElapsedTime",et)

Stores current time if first time through, otherwise calculate elapsed time

get_timer(“index”)
  • returns 1 or 2 values
  • First return value(Boolean) is true if timer is active(counting down) or false if timer is expired or has not been set yet
  • Second return value is the number of seconds remaining or -1 if timer is not active or has not been set yet

Example:

if not get_timer("myTimer") then
    set_sGbl("timedOut",true)
else
    set_sGbl("timedOut",false)
end

if timer is expired, then set global status “timedOut” to true

local active,remaining = get_timer("myTimer")
if not active then
    set_sVirt("timeRemaining","Expired")
else
    set_sVirt("timeRemaining",remaining)
end
getStateLabel(state)
  • return the label for the engine state corresponding to the parameter state

Example:

local stateLabel = getStateLabel(get_state())
local active, remaining = get_timer("myTimer")
if remaining > 0 then
    stateLabel == StateLabel.." "..remaining
end
set_sVirt("Countdown",stateLabel)
set_sGbl(“index”,value)
  • store value in the global status table under index
  • value can be a number or string but if storing a boolean use the tostring() function

Example:

local mpe = false
local sp = get_channel_val(1,5)
if sp > 15 then
    mpe = true
end
set_sGbl("minPressureExceeded",tostring(mpe))

store boolean value minPressureExceeded

set_sVirt(“index”,value)

  • sets a virtual status channel with channel name index

    Note: Once you create a virtual channel, you can add that channel to the dashboard using the channel name index

Example:

local sp = get_channel_val(1,5) --suction pressure
local dp = get_channel_val(1,6) --discharge pressure
local diffPress = dp - sp
set_sVirt("SuctDischDiff",diffPress)

calculate the differential between suction and discharge pressure and assign to virtual channel

set_timer(“index”,secs)
  • activate timer index and set countdown time to secs

Example:

set_timer("myTimer",300)

create timer myTimer and start countdown time to 300 seconds

Master Control Script

When you enter a control setup under the Global Control page the code that runs is called MasterControl.

If you wish to modify this functionality you can copy this code into the Control Script editor and make your changes to the standard configuration.

 local rampRate1 = get_gbl("rampRate1",0.8)
  local rampRate2 = get_gbl("rampRate2",0.8)
  local dischTerm = tonumber_def(get_gbl("spDischTerm",0),0)
  local dischChan = tonumber_def(get_gbl("spDischChan",0),0)
  local suctTerm = tonumber_def(get_gbl("spSuctTerm",0),0)
  local suctChan = tonumber_def(get_gbl("spSuctChan",0),0)
  local suctMin = tonumber_def(get_gbl("suctMin",0),0)
  local recycleMin = tonumber_def(get_gbl("recycleMin",0),0)
  local recycleMax = tonumber_def(get_gbl("recycleMax",0),0)
  local suctSp = tonumber_def(get_gbl("suctSp",0),0)
  local dischMax = tonumber_def(get_gbl("dischMax",0),0)
  local dischSp = tonumber_def(get_gbl("dischSp",0),0)
  local outputTerm = tonumber_def(get_gbl("outputTerm",0),0)
  local outputChan = tonumber_def(get_gbl("outputChan",0),0)
  local recycleTerm = tonumber_def(get_gbl("outputTerm2",0),0)
  local recycleChan = tonumber_def(get_gbl("outputChan2",0),0)
  local speedRevAct = tonumber_def(get_gbl("speedRevAct",0),0)
  local recycleRevAct = tonumber_def(get_gbl("recycleRevAct",0),0)
  local outputLow = tonumber_def(get_gbl("outputLow",0),0)
  local outputLow2 = tonumber_def(get_gbl("outputLow2",0),0)
  local outputHigh = tonumber_def(get_gbl("outputHigh",0),0)
  local outputHigh2 = tonumber_def(get_gbl("outputHigh2",0),0)
  local spSuctType = get_gbl("spSuctType","linear")
  local spDischType = get_gbl("spDischType","linear")
  local suctPIDPFactor = tonumber_def(get_gbl("suctPIDPFactor",0),0)
  local suctPIDIFactor = tonumber_def(get_gbl("suctPIDIFactor",0),0)
  local suctPIDDFactor = tonumber_def(get_gbl("suctPIDDFactor",0),0)
  local dischPIDPFactor = tonumber_def(get_gbl("dischPIDPFactor",0),0)
  local dischPIDIFactor = tonumber_def(get_gbl("dischPIDIFactor",0),0)
  local dischPIDDFactor = tonumber_def(get_gbl("dischPIDDFactor",0),0)
  local recycleCtrl = false
  local recycleSuctionRev = false
  local recycleDischargeRev = false
  if recycleChan > 0 and recycleTerm > 0 then
    recycleCtrl = true
  end
 
  local dischPct = 100
  local suctPct = 100
 
 
  local dischOutput = 0
  local suctOutput = 0
  local rSuctOutput = 0
  local rDischOutput = 0
  local minLoad = 0
  local maxLoad = 100
  local minRecycle = 0
  local maxRecycle = 100
  local speedTarget = get_sGbl("speedTarget",0)
  local recycleTarget = get_sGbl("recycleTarget",0)
 
  function map_range(rangeLow,rangeHigh,input)
    if input <= rangeLow and input <= rangeHigh then
      return 0
    end
    if input >= rangeLow and input >= rangeHigh then
      return 100
    end
    local rangeDiff = math.abs(rangeLow - rangeHigh)
    local min = math.min(rangeLow,rangeHigh)
    local retval = math.abs(input - min) / rangeDiff * 100
    if retval > 100 then retval = 100 end
    if retval < 0 then retval = 0 end
    return retval
  end
 
  local suct = false
  local suctVal = 0
  if tonumber_def(get_gbl("spSuctEn",0),0) == 1 then
    if suctTerm > 0 and suctChan > 0 then
      suctVal = get_channel_val(suctTerm,suctChan)
      suct = true
    end
  end
 
 
  if suct then
    if spSuctType == "linear" then
      local suctDiff = suctSp - suctMin
      if suctDiff == 0 then suctDiff = 1 end
      if suctVal < suctSp then
        local suctErr = suctSp - suctVal
        suctPct = suctErr / suctDiff
        if suctPct > 1 then suctPct = 1 end
        if suctPct < 0 then suctPct = 0 end
        suctOutput = (1 - suctPct) * 100
      else
        suctOutput = 100
      end
    else
      set_gbl("PIDsuctEnable",1)
      set_gbl("PIDsuctPFactor",suctPIDPFactor)
      set_gbl("PIDsuctIFactor",suctPIDIFactor)
      set_gbl("PIDsuctDFactor",suctPIDDFactor)
      set_gbl("PIDsuctSp",suctSp)
      set_gbl("PIDsuctDeadband",0.2)
      local suctPidOutput = doPid("suct",suctVal)
      suctOutput = suctPidOutput
    end
  else
    suctOutput = 100
  end
 
 
  local disch = false
  local dischVal = 0
  if tonumber_def(get_gbl("spDischEn",0),0) == 1 then
    if dischTerm > 0 and dischChan > 0 then
        dischVal = get_channel_val(dischTerm,dischChan)
        disch = true
    end
  end
  if disch then
    if spDischType == "linear" then
      local dischDiff = dischMax - dischSp
      if dischDiff == 0 then dischDiff = 1 end
      if dischVal > dischSp then
        local dischErr = dischVal - dischSp
        dischPct = dischErr / dischDiff
        if dischPct > 1 then dischPct = 1 end
        if dischPct < 0 then dischPct = 0 end
        dischOutput = (1 - dischPct) * 100
      else
        dischOutput = 100
      end
    else
      set_gbl("PIDdischEnable",1)
      set_gbl("PIDdischPFactor",dischPIDPFactor)
      set_gbl("PIDdischIFactor",dischPIDIFactor)
      set_gbl("PIDdischDFactor",dischPIDDFactor)
      set_gbl("PIDdischSp",dischSp)
      set_gbl("PIDdischRevAct",1)
      set_gbl("PIDdischDeadband",0.2)
      local dischPidOutput = doPid("disch",dischVal)
      dischOutput = dischPidOutput
    end
  else
    dischOutput = 100
  end
 
 
  local minOutput = 100
  local winning = 0
  if suctOutput < minOutput then
    minOutput = suctOutput
    winning = 1
  end
  if dischOutput < minOutput then
    minOutput = dischOutput
    winning = 2
  end
 
  if suctOutput == dischOutput then
    winning = 0
  end
 
  if winning == 0 then
    set_gbl("PIDsuctMax",100)
    set_gbl("PIDdischMax",100)
  end
 
  if winning == 1 then
    set_gbl("PIDdischMax",math.min(suctOutput + 2,100))
    set_gbl("integraldisch",0)
    set_gbl("lastErrdisch",0)
    set_gbl("outputSumdisch",0)
    set_gbl("PIDsuctMax",100)
  end
  if winning == 2 then
    set_gbl("PIDsuctMax",math.min(dischOutput + 2,100))
    set_gbl("integralsuct",0)
    set_gbl("lastErrsuct",0)
    set_gbl("outputSumsuct",0)
    set_gbl("PIDdischMax",100)
  end
 
  local recycleMinOutput = minOutput
 
  local manOutput = 0
  --********************************************************************
  local manMode = 0
  local manTerm = tonumber_def(get_gbl("manTerm",0),0)
  local manChan = tonumber_def(get_gbl("manChan",0),0)
  if manTerm > 0 and manChan > 0 then
    local manInput = get_channel_val(manTerm,manChan)
    if manInput > 0.5 then
      manMode = 0
      set_sVirt("SpeedControl","Auto")
    else
      manMode = 1
      set_sVirt("SpeedControl","Manual")
    end
  else
    if get_sVirt("SpeedControl","Auto") == "Auto" then
      manMode = 0
    else
      manMode = 1
    end
  end
 
  --if manMode == 1 and get_state() == 8 then
  local manSpeed = get_sVirt("ManualSpeed",0)
  local idleSpeed = get_gbl("idleSpeed",0)
  local lowSpeed = get_gbl("lowSpeed",0)
  local highSpeed = get_gbl("highSpeed",0)
  local maxSpeed = get_gbl("maxSpeed",0)
  local diff = highSpeed - lowSpeed
  if diff < 0 then diff = 0 end
  local maxDiff = maxSpeed - idleSpeed
  if maxDiff < 0 then maxDiff = 0 end
 
  if get_sVirt("speedBump",0) ~= 0 then
    local si = get_gbl("SpeedIncrement",0)
    local sip = get_param("SpeedIncrement",0)
    if sip ~= 0 then si = sip end
    manSpeed = manSpeed + (si * get_sVirt("speedBump",0))
    set_sVirt("speedBump",0)
  end
 
  if get_sVirt("AutoManBump",0) > 0 then
    set_sVirt("SpeedControl","Auto")
    set_sVirt("AutoManBump",0)
  end
 
  if get_sVirt("AutoManBump",0) < 0 then
    set_sVirt("SpeedControl","Manual")
    set_sVirt("AutoManBump",0)
  end
 
  if manMode == 1 then
    local manSpeedTerm = tonumber_def(get_gbl("manSpeedTerm",0),0)
    local manSpeedChan = tonumber_def(get_gbl("manSpeedChan",0),0)
    if manSpeedTerm > 0 and manSpeedChan > 0 then --*** USE SPEED POT TO SET SPEED
      local speedInput = tonumber(get_channel_val(manSpeedTerm,manSpeedChan))
      local speedPct = (speedInput / 5) * 100
      if speedPct > 100 then speedPct = 100 end
      if speedPct < 0 then speedPct = 0 end
      manOutput = speedPct
      manSpeed = math.floor((speedPct / 100) * diff + lowSpeed + 0.5)
    else -- Use ManualSpeed to set speed
      manOutput = ((manSpeed - lowSpeed) / diff) * 100.0
      if manOutput < 0 then manOutput = 0 end
      if manOutput > 100 then manOutput = 100 end
    end
    minOutput = manOutput
  else
    --speedTarget =
    local stRpm = (speedTarget/100) * maxDiff + idleSpeed
    if stRpm < lowSpeed then stRpm = lowSpeed end
    if stRpm > highSpeed then stRpm = highSpeed end
    manSpeed = math.floor(stRpm)
  end
 
  if manSpeed < lowSpeed then
    manSpeed = lowSpeed
  end
  if manSpeed > highSpeed then
    manSpeed = highSpeed
  end
 
  set_sVirt("ManualSpeed",manSpeed)
 
 
 
  --********************************************************************
 
 
  local output1 = 0
  local output2 = 0
  if spSuctType == "pid" or spDischType == "pid" then
    output1 = map_range(outputLow,outputHigh,minOutput)
    set_sVirt("out1",output1)
    output2 = map_range(outputLow2,outputHigh2,recycleMinOutput)
    set_sVirt("out2",output2)
    local hasRPM = idleSpeed > 0 and lowSpeed > 0 and highSpeed > 0 and maxSpeed > 0
    if outputTerm and outputChan then
      if hasRPM then
        local speedRpm = output1 / 100  * (highSpeed - lowSpeed) + lowSpeed
        speedTarget = (speedRpm - idleSpeed) / (maxSpeed - idleSpeed) * 100
      else
        speedTarget = output1
      end
    end
    if recycleTerm and recycleChan then
      set_ao_val(recycleTerm,recycleChan,output2)
    end
 
    if get_state() == 9 then
      speedTarget = get_sGbl("speedTarget",0)
      if speedTarget > 0 then speedTarget = speedTarget - rampRate1 end
      if speedTarget < 0 then speedTarget = 0 end
    end
    if get_state() < 8 then speedTarget = 0 end
    set_sGbl("speedTarget",speedTarget)
    set_ao_val(outputTerm,outputChan,speedTarget)
    set_sVirt("spTarget",speedTarget)
 
    if hasRPM then
      local sRpm = (speedTarget/100) * maxDiff + idleSpeed
      set_sVirt("Speed Target",math.floor(sRpm + 0.5))
    end
 
 
 
  else
 
    -- Remember that minOutput is 0 - 100 pct of lowSpeed <-> highSpeed
    -- We need to convert this to 0 - 100 pct of idleSpeed <-> maxSpeed
    local suctPct = map_range(outputLow,outputHigh,minOutput)
    local speedRpm = suctPct / 100  * (highSpeed - lowSpeed) + lowSpeed
    minOutput = (speedRpm - idleSpeed) / (maxSpeed - idleSpeed) * 100
 
 
 
    if minOutput <= speedTarget then
      speedTarget = speedTarget - rampRate1
      if speedTarget < minOutput then speedTarget = minOutput end
    else
        speedTarget = speedTarget + rampRate1
        if speedTarget > minOutput then speedTarget = minOutput end
        if speedTarget > maxLoad then speedTarget = maxLoad end
    end
    if speedTarget > maxLoad then speedTarget = maxLoad end
    if speedTarget < minLoad then speedTarget = minLoad end
 
    if recycleCtrl then
      local recyclePct = map_range(outputLow2,outputHigh2,recycleMinOutput)
      if recyclePct <= recycleTarget then
        recycleTarget = recycleTarget - rampRate2
        if recycleTarget < recyclePct then recycleTarget = recyclePct end
      else
        recycleTarget = recycleTarget + rampRate2
        if recycleTarget > recyclePct then recycleTarget = recyclePct end
      end
      if recycleTarget > maxRecycle then recycleTarget = maxRecycle end
      if recycleTarget < minRecycle then recycleTarget = minRecycle end
      local recycleOutput = recycleTarget
      if get_state() < 8 then
        recycleTarget = 0
      end
      if recycleRevAct == 1 then
        recycleOutput = 100 - recycleOutput
      end
      set_ao_val(recycleTerm,recycleChan,recycleOutput)
      set_sGbl("recycleTarget",recycleTarget)
      set_sVirt("recycleTarget",recycleTarget)
    end
 
    if get_state() == 9 then
      speedTarget = get_sGbl("speedTarget",0)
      if speedTarget > 0 then speedTarget = speedTarget - rampRate1 end
      if speedTarget < 0 then speedTarget = 0 end
    end
    if get_state() < 8 then speedTarget = 0 end
    set_sGbl("speedTarget",speedTarget)
    set_ao_val(outputTerm,outputChan,speedTarget)
    set_sVirt("spTarget",speedTarget)
    local sRpm = (speedTarget/100) * maxDiff + idleSpeed
    set_sVirt("Speed Target",math.floor(sRpm + 0.5))
 
 
  end

Handling Special Characters in Strings

When scripting in Lua for the DE-4000 system, it is important to correctly handle special characters within strings to prevent errors. This is especially critical when passing strings to functions like Custom Fault and others.

Special Characters in Strings
Non-alphanumeric characters, such as %, “, and others, can cause issues in Lua if not properly escaped. Below are some common cases and their solutions.

  • Escaping the % Character
  • Issue: The % symbol is treated as a special character in Lua and needs to be escaped.
    Solution: Use %% to represent a literal % in a string.

Example: Escaping %

local faultMessage = "Current value is 50%% over the limit."
custom_fault(faultMessage)
  • In this example, %% ensures that the % is displayed as a literal percentage sign.

Best Practices for Strings with Special Characters

  • Always escape non-alphanumeric characters when constructing strings for Lua functions.
  • Review strings passed to critical functions like custom_fault or similar to ensure all special characters are properly escaped.

Summary

  • Use %% for %, double quotes (“”) for “, and backslashes (\\) for \.
  • Follow Lua’s conventions for escaping special characters to ensure robust script execution.
  • Consider implementing automated escaping in custom functions to simplify user scripting efforts.