PowerShell PRTG Advanced Custom Sensor XML output

Hello,

this static ps script works as expected: {{{ $XMLResult = @" <prtg><result><channel>Server 1</channel><value>0</value></result><result><channel>Server 2</channel><value>1</value></result><result><channel>Server 3</channel><value>2</value></result></prtg> "@

Write-Host $XMLResult }}}

but I want to build the above result during runtime in a variable like this: {{{ $XMLResult = @" $myString "@

Write-Host $XMLResult }}}

or like this: {{{ $XMLResult = @" $($myString) "@

Write-Host $XMLResult }}}

The sensor shows Code: PE233 and Code: PE231error message when using a variable although the scripts have the exactly output when running from command line.

Can someone please provide an example for building channels dynamically during runtime?

Thank you in advance