I tested the same Cmdlet and can't regenerate the same error what you got.

PS C:\> Get-Module -Name Dell.PowerMax -ListAvailable | Select-Object Version

Version
-------
2.0.0.89

$unisphere_da = Connect-Unisphere -HostName 12.34.56.89 -UseSaved

PS C:\EMCPowerMax> Get-Srp -Unisphere $unisphere_da -ArrayId 000120002345 | ft -au

Id    Description Emulation ReservedCapPercent NumOfDiskGroups RdfaDse
--    ----------- --------- ------------------ --------------- -------
SRP_1             FBA       10                 1               True

@Fun2Share​ Thank you for the reply.

Run the cmdlet and show all properties.

Get-Srp -Unisphere $unisphere_da -ArrayId 000120002345 | Select-Object -Property *

EffectiveUsedCapacityPercent does not show the same as in Unisphere GUI here.

The PowerShell module for PowerMax will go end of life Q2 next year and I will rewrite my scripts and use Invoke-RestMethod.

/Magnus