Get-Uptime.ps1

#requires -Version 2 -Modules CimCmdlets
function Get-Uptime 
{
    <#
            .SYNOPSIS
            Get Computer Uptime

            .DESCRIPTION
            Get the uptime of a Computer Object by using CIM.

            .PARAMETER ComputerName
            This parameter accepts multiple entries. Check the example for how to do this.

            .INPUTS
            This script accepts a single or array (of) strings as a input for the ComputerName parameter.

            .OUTPUTS
            Description of objects that are output by the script

            .EXAMPLE
            Retrieve uptime of a single computer object

            Get-Uptime -ComputerName 'server01.domain.com'

            .EXAMPLE
            Retrieve Uptime of multiple computer objects

            Get-Uptime -ComputerName 'server01.domain.com','server02.domain.com','server03.domain.com'

            .EXAMPLE
            Retrieve Uptime of multiple computer object and output to CSV

            Get-Uptime -ComputerName 'server01.domain.com','server02.domain.com','server03.domain.com' | Export-Csv -Path 'C:\Temp\output.csv' -NoTypeInformation

            .EXAMPLE
            Retrieve computer server objects from Active Directory, and get the uptime

            $adComputers = Get-ADComputer -Filter {OperatingSystem -Like "*Windows Server*"} | Select DNSHostName
            $adComputers | ForEach-Object -Process { Get-Uptime -ComputerName $_.DNSHostName }

            .LINK
            http://quantica.nl

            .NOTES
            Version: 1.0
            Author: Richard Diphoorn
            
            Twitter: http://twitter.com/rdtechie
            Blog: http://powershell.org
            Private Blog: http://quantica.nl

            Creation Date: 2015-07-08 
            Purpose/Change: Initial Release

    #>

    [CmdletBinding()]
    Param(
        [Parameter(ValueFromPipeline = $True)][string[]]$ComputerName
    )
    
    #region Initialization Code
    try 
    {
        $computerObjects = Get-CimInstance -ComputerName $ComputerName -ClassName Win32_OperatingSystem -ErrorAction SilentlyContinue
    }
    catch 
    {
        Write-Warning -Message $_.Exception.Message
    }
    #endregion Initialization Code
    
    #region Process Code    
    try 
    {
        foreach ($computerObject in $computerObjects) 
        {
            $upTimeDays = (New-TimeSpan -Start (Get-Date -Date $computerObject.LastBootUpTime.Ticks) -End (Get-Date)).TotalDays
            $upTimeHours = (New-TimeSpan -Start (Get-Date -Date $computerObject.LastBootUpTime.Ticks) -End (Get-Date)).TotalHours
    
            #region Constructing Output Object
            New-Object -TypeName PSCustomObject -Property ([ordered] @{
                    'Computername' = $computerObject.CSName
                    'LastBootTime' = $computerObject.LastBootUpTime
                    'UptimeDays' = [math]::Round($upTimeDays,0)
                    'UptimeHours' = [math]::Round($upTimeHours,1)
            })#endregion Contructing Output Object
        }
    }
    catch 
    {
        Write-Warning -Message $_.Exception.Message
    }
    #endregion Process Code
}

Test comment.