diff --git a/OOequipment/Equipment.m b/OOequipment/Equipment.m
index f9ca1d2..6c4de88 100644
--- a/OOequipment/Equipment.m
+++ b/OOequipment/Equipment.m
@@ -9,32 +9,51 @@ classdef Equipment < handle
     end
     
     methods
-        function DMM = equipment(name,connection,channel)
-            DMM.name = name;
-            DMM.tcp = tcpip(connection,1234);
-            DMM.channel = channel;
+        function ecq = Equipment(name,ipAddress,port,channel)
+            ecq.name = name;
+            ecq.tcp = Equipment.getTCP(ipAddress,port);
+            ecq.channel = channel;
         end
-        function idn(DMM)
-            fprintf(DMM.tcp,['++addr ',num2str(DMM.channel)]);
-            fprintf(DMM.tcp,'*idn?');
-            fprintf(DMM.tcp,'++read');
-            fprintf(fscanf(DMM.tcp));
+        function idn(ecq)
+            fprintf(ecq.tcp,['++addr ',num2str(ecq.channel)]);
+            fprintf(ecq.tcp,'*idn?');
+            fprintf(ecq.tcp,'++read');
+            fprintf(fscanf(ecq.tcp));
         end
         function starttcp(DMM)
             fopen(DMM.tcp);
         end
     end
     methods (Static)
-        function getTCP(ipAddress)
-            persistent stored_ipaddress;
-            if ~isempty(stored_ipaddress)
-                ipaddress = stored_ipaddress;
-                return
+        function tcpobject = getTCP(ipAddress,port)
+            persistent tcpconnection;
+            ipname = Equipment.ip2structname(ipAddress);
+            if isempty(tcpconnection)
+                tcpconnection = struct;
+            end
+            
+            if ~isfield(tcpconnection, ipname)
+                tcpconnection.(ipname).tcp = tcpip(ipAddress,port);
+                tcpconnection.(ipname).nopen = 1;
+                fopen(tcpconnection.(ipname).tcp);
+            else
+                tcpconnection.(ipname).nopen = tcpconnection.(ipname).nopen + 1;
+            end
+            tcpobject = tcpconnection.(ipname).tcp;
+        end
+        
+        function iptest(ipAddress)
+            validip = regexp(ipAddress,'^(?:(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9]))$', 'once');
+            if isempty(validip)
+                error('Invalid IP-address');
             end
         end
+        function structname = ip2structname(ipAddress)
+            Equipment.iptest(ipAddress);
+            ipmatch = regexprep(ipAddress,'\.','_');
+            structname = ['ip',ipmatch];
+        end
     end
-    
-    
 end
 
 % classdef BankAccount < handle
diff --git a/OOequipment/function_generator.m b/OOequipment/function_generator.m
deleted file mode 100644
index c443fca..0000000
--- a/OOequipment/function_generator.m
+++ /dev/null
@@ -1,12 +0,0 @@
-classdef function_generator
-    %FUNCTION_GENERATOR Summary of this class goes here
-    %   Detailed explanation goes here
-    
-    properties
-    end
-    
-    methods
-    end
-    
-end
-