diff --git a/dstat_interface/dstat_comm.py b/dstat_interface/dstat_comm.py
index 46e30a2d4d5f081d5b1a8220d78d910c072c4448..56e0baa7125b6dc490798c942a462ddf4de82f73 100644
--- a/dstat_interface/dstat_comm.py
+++ b/dstat_interface/dstat_comm.py
@@ -844,6 +844,17 @@ class OCPExp(Experiment):
         seconds, milliseconds, voltage = struct.unpack('<HHl', data)
         return (voltage/5.592405e6)
         
+class PMTIdle(Experiment):
+    """Open circuit potential measumement in statusbar."""
+    def __init__(self):
+        self.databytes = 8
+    
+        self.commands = ["EA", "EM"]
+    
+        self.commands[0] += "2 " # input buffer
+        self.commands[0] += "3 " # 2.5 Hz sample rate
+        self.commands[0] += "1 " # 2x PGA
+        
 def measure_offset(time):
     gain_trim_table = [None, 'r100_trim', 'r3k_trim', 'r30k_trim', 'r300k_trim',
                         'r3M_trim', 'r30M_trim', 'r100M_trim']
diff --git a/dstat_interface/interface/dstatinterface.glade b/dstat_interface/interface/dstatinterface.glade
index cf2ab147d0c6a794d6d20b58c5b7c2bf0475642b..ba77bd2164babfcf93bd8354eeb1d7a942e86964 100644
--- a/dstat_interface/interface/dstatinterface.glade
+++ b/dstat_interface/interface/dstatinterface.glade
@@ -1235,6 +1235,20 @@ Thanks to Christian Fobel for help with Dropbot Plugin</property>
                 <property name="position">3</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkButton" id="pmt_mode">
+                <property name="label" translatable="yes">Connect (PMT mode)</property>
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="receives_default">True</property>
+                <signal name="clicked" handler="on_pmt_mode_clicked" swapped="no"/>
+              </object>
+              <packing>
+                <property name="expand">False</property>
+                <property name="fill">False</property>
+                <property name="position">4</property>
+              </packing>
+            </child>
             <child>
               <object class="GtkButton" id="serial_disconnect">
                 <property name="label">gtk-disconnect</property>
@@ -1247,7 +1261,7 @@ Thanks to Christian Fobel for help with Dropbot Plugin</property>
               <packing>
                 <property name="expand">False</property>
                 <property name="fill">False</property>
-                <property name="position">4</property>
+                <property name="position">5</property>
               </packing>
             </child>
             <child>
@@ -1262,7 +1276,7 @@ Thanks to Christian Fobel for help with Dropbot Plugin</property>
               <packing>
                 <property name="expand">False</property>
                 <property name="fill">False</property>
-                <property name="position">5</property>
+                <property name="position">6</property>
               </packing>
             </child>
             <child>
@@ -1274,7 +1288,7 @@ Thanks to Christian Fobel for help with Dropbot Plugin</property>
               <packing>
                 <property name="expand">True</property>
                 <property name="fill">True</property>
-                <property name="position">6</property>
+                <property name="position">7</property>
               </packing>
             </child>
           </object>
diff --git a/dstat_interface/main.py b/dstat_interface/main.py
index 98823f9681b68eab3cb62ef27e9f6004bdc22908..a6e61185beb77ecd1b181a0331dc65b425a251f4 100755
--- a/dstat_interface/main.py
+++ b/dstat_interface/main.py
@@ -94,6 +94,7 @@ class Main(object):
         
         #fill serial
         self.serial_connect = self.builder.get_object('serial_connect')
+        self.serial_pmt_connect = self.builder.get_object('pmt_mode')
         self.serial_disconnect = self.builder.get_object('serial_disconnect')
         self.serial_disconnect.set_sensitive(False)
         self.serial_combobox = self.builder.get_object('serial_combobox')
@@ -125,6 +126,7 @@ class Main(object):
         self.expnumber = 0
         
         self.connected = False
+        self.pmt_mode = False
         
         self.menu_dropbot_connect = self.builder.get_object(
                                                          'menu_dropbot_connect')
@@ -187,10 +189,11 @@ class Main(object):
                                 )
                                 
                 comm.read_settings()
-
+                
                 self.start_ocp()
                 self.connected = True
                 self.serial_connect.set_sensitive(False)
+                self.serial_pmt_connect.set_sensitive(False)
                 self.serial_disconnect.set_sensitive(True)
         
         except AttributeError as err:
@@ -217,21 +220,38 @@ class Main(object):
             _logger.error(err, 'WAR')
             pass
         
+        self.pmt_mode = False
         self.connected = False
         self.serial_connect.set_sensitive(True)
+        self.serial_pmt_connect.set_sensitive(True)
         self.serial_disconnect.set_sensitive(False)
+        self.adc_pot.short_toggle.set_sensitive(True)
+    
+    def on_pmt_mode_clicked(self, data=None):
+        """Connect in PMT mode"""
+        self.pmt_mode = True
+        self.adc_pot.short_toggle.set_active(True)
+        self.adc_pot.short_toggle.set_sensitive(False)
+        self.on_serial_connect_clicked()
 
     def start_ocp(self):
         """Start OCP measurements."""
+        
         if self.version[0] >= 1 and self.version[1] >= 2:
             # Flush data pipe
             while comm.serial_instance.data_pipe_p.poll():
                 comm.serial_instance.data_pipe_p.recv()
             
-            _logger.error("Start OCP", "INFO")
-            comm.serial_instance.proc_pipe_p.send(comm.OCPExp())
-            self.ocp_proc = (gobject.idle_add(self.ocp_running_data),
-                             gobject.idle_add(self.ocp_running_proc)
+            if self.pmt_mode == True:
+                _logger.error("Start PMT idle mode", "INFO")
+                comm.serial_instance.proc_pipe_p.send(comm.PMTIdle())
+            
+            else:
+                _logger.error("Start OCP", "INFO")
+                comm.serial_instance.proc_pipe_p.send(comm.OCPExp())
+                
+            self.ocp_proc = (gobject.timeout_add(300, self.ocp_running_data),
+                             gobject.timeout_add(250, self.ocp_running_proc)
                             )
             self.ocp_is_running = True
             
@@ -241,8 +261,12 @@ class Main(object):
         
     def stop_ocp(self):
         """Stop OCP measurements."""
+
         if self.version[0] >= 1 and self.version[1] >= 2:
-            _logger.error("Stop OCP",'INFO')
+            if self.pmt_mode == True:
+                _logger.error("Stop PMT idle mode",'INFO')
+            else:
+                _logger.error("Stop OCP",'INFO')
             comm.serial_instance.ctrl_pipe_p.send('a')
 
             for i in self.ocp_proc:
@@ -276,7 +300,9 @@ class Main(object):
                                 "{0:.3f}".format(incoming),
                                 " V"])
                 self.ocp_disp.set_text(data)
-    
+                
+                if comm.serial_instance.data_pipe_p.poll():
+                    self.ocp_running_data()
                 return True
             
             return True