Create an EventLog and a LogFile.

EventLog_File.ps1

function Create-ScriptEventLog
{
    [CmdletBinding()]
    Param
    (
        [Parameter(Mandatory=$True,
                   Position=1)]
        [string]$Source = "",

        [Parameter(Mandatory=$false,
                   Position=0)]
        [string]$LogName = "ScriptHealthCheck"
    )

    Begin
    {
    }
    Process
    {
        if (!(Get-EventLog -list | where {$_.logdisplayname -eq $LogName})){
            New-EventLog -Source $Source -LogName $LogName
        }
        else {
        Write-Error "$LogName Log has already been created"
        }
    }
    End
    {
    }
}


function Write-ScriptEventLog
{
    [CmdletBinding(DefaultParameterSetName="Default")]
    [Alias()]
    Param
    (
        

        [Parameter(
            Mandatory=$True,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Default",
            Position=1
        )]
         [Parameter(
            Mandatory=$True,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Non-Default",
            Position=2
            )]
        [ValidateSet ("Info","Warning","Error")]
        $ErrorType,

        [Parameter(
            Mandatory=$True,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Default",
            Position=0
        )]
        [Parameter(
            Mandatory=$True,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Non-Default",
            Position=3
            )]
        [string]$Message,

        [Parameter(
            Mandatory=$True,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Default",
            Position=2
        )]
        [Parameter(
            Mandatory=$True,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Non-Default",
            Position=5
        )]        
        [int]$Category,

        [Parameter(
            Mandatory=$True,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Default",
            Position=3
        )]
         [Parameter(
            Mandatory=$True,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Non-Default",
            Position=4
            )]
        [int]$EventID,

        [Parameter(
            Mandatory=$False,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Non-Default",
            Position=0
        )]
        $LogName = "ScriptHealthCheck",

        [Parameter(
            Mandatory=$false,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Non-Default",
            Position=1
        )]
        $Source = (Get-Variable -Scope 1 -Name MyInvocation).value.MyCommand.Name,

        [Parameter(
            Mandatory=$False,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Default"
        )]
         [Parameter(
            Mandatory=$False,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName="Non-Default"
            )]
        [string]$LogFile = "C:\Script\HealthCheck.log"
    )

    Begin
    {
        $Date = Get-Date 
    }
    Process
    {
        if ([System.Diagnostics.EventLog]::SourceExists($Source)){
            Write-EventLog -LogName $logname -Source $Source -EntryType $ErrorType -Message $Message -Category $Category -EventId $EventID
        }
        else {
            New-EventLog -LogName $logname -Source $Source
            Write-EventLog -LogName $logname -Source $Source -EntryType $ErrorType -Message $Message -Category $Category -EventId $EventID
        }
        try{
        Out-File $LogFile -NoClobber string -InputObject "$Date : $Source : $ErrorType : $Message" -Append
        }
        catch {
            Write-Error "Could not write to the log file, please check the Log file: $LogFile"
        }
    }
    End
    {
    }
}