List servers by site in AD

I have a script I am trying to run to list servers in a specific AD site. I am changing all of our DNS server info with a script, but need to break down our server list by site for the input file. 

I found this one online, but cant seem to get it to work right in my test lab. 

Thank you

$siteName =   "Default-First-Site-Name"
$configNCDN = (Get-ADRootDSE).ConfigurationNamingContext
$siteContainerDN = ("CN=Sites," + $configNCDN)
$serverContainerDN = "CN=Servers,CN=" + $siteName + "," + $siteContainerDN
Get-ADObject -SearchBase $serverContainerDN -SearchScope OneLevel -filter {objectClass}