In ModbusBase.vb, go to about line 290 and look for this code:
Private SubscriptionList As New List(Of SubscriptionInfo)
and change the Private to Public
You can then see the list
for i=0 to ModbusTCPCom1.SubscriptionList.Count-1
Console.WriteLine(ModbusTCPCom1.SubscriptionList(i).Address.Address)
Next