Hi,
I used the below provided PS sample. Let me know if this solves your need.
$xmlParam = ([xml]"
<CorePluginConfigurationContext xmlns:i='http://www.w3.org/2001/XMLSchema-instance' xmlns='http://schemas.solarwinds.com/2012/Orion/Core'>
<BulkList />
<IpRanges />
<Subnets>
<AddressSubnet><SubnetIP>XX.XXX.X.XXX</SubnetIP><SubnetMask>255.255.0.0</SubnetMask></AddressSubnet>
</Subnets>
<Credentials />
<WmiRetriesCount>0</WmiRetriesCount>
<WmiRetryIntervalMiliseconds>0</WmiRetryIntervalMiliseconds>
</CorePluginConfigurationContext>"
).DocumentElement
$PlugInConfiguration = Invoke-SwisVerb $swis "Orion.Discovery" "CreateCorePluginConfiguration" @($xmlParam)
$coreCfgText = $PlugInConfiguration.InnerXml
$startDiscoveryParam = ([xml]@("
<StartDiscoveryContext xmlns:i='http://www.w3.org/2001/XMLSchema-instance' xmlns='http://schemas.solarwinds.com/2012/Orion/Core'>
<Name>AutomaticDiscovery2</Name>
<EngineId>1</EngineId>
<JobTimeoutSeconds>3600</JobTimeoutSeconds>
<SearchTimeoutMiliseconds>2000</SearchTimeoutMiliseconds>
<SnmpTimeoutMiliseconds>2000</SnmpTimeoutMiliseconds>
<SnmpRetries>1</SnmpRetries>
<RepeatIntervalMiliseconds>1500</RepeatIntervalMiliseconds>
<SnmpPort>161</SnmpPort>
<HopCount>0</HopCount>
<PreferredSnmpVersion>SNMP2c</PreferredSnmpVersion>
<DisableIcmp>false</DisableIcmp>
<AllowDuplicateNodes>false</AllowDuplicateNodes>
<IsAutoImport>true</IsAutoImport>
<IsHidden>false</IsHidden>
<PluginConfigurations>",
"<PluginConfiguration>
<PluginConfigurationItem>$coreCfgText</PluginConfigurationItem>
</PluginConfiguration>",
"</PluginConfigurations>
</StartDiscoveryContext>"
)).DocumentElement
Invoke-SwisVerb $swis "Orion.Discovery" "StartDiscovery" @($startDiscoveryParam) | Out-Null