diff -r 3f123b64d367 -r 4cbd3d410230 pygpibtoolkit/plotter/qgpib_plotter.py
--- a/pygpibtoolkit/plotter/qgpib_plotter.py	Fri May 18 01:07:28 2018 +0200
+++ b/pygpibtoolkit/plotter/qgpib_plotter.py	Sun Jun 03 18:04:11 2018 +0200
@@ -19,9 +19,10 @@
 import time
 
 from PyQt5 import QtWidgets, QtGui, QtCore, QtPrintSupport, uic
-from PyQt5.QtCore import Qt
+from PyQt5.QtCore import Qt, pyqtSignal
 
 from pygpibtoolkit.plotter.hpgl_qt import QHPGLPlotterWidget
+from pygpibtoolkit.plotter.gpib_plotter import GPIBplotter
 
 from pygpibtoolkit.qt5.qpreferences import IntItem, UnicodeItem, ColorItem
 from pygpibtoolkit.qt5.qpreferences import BoolItem
@@ -40,14 +41,10 @@
         os.path.join(HERE, "qhpgl_plotter.ui"),
         from_imports=True, import_from='pygpibtoolkit.plotter',)
 except Exception as e:
-    print(e)
-    from pygpibtoolkit.plotter.qhpgl_plotter_ui import Ui_MainWindow as form_class
+    from pygpibtoolkit.plotter.qhpgl_plotter_ui import (
+        Ui_MainWindow as form_class)
 
 
-if "-m" in sys.argv:
-    from pygpibtoolkit.plotter.gpib_plotter_mockup import GPIBplotter
-else:
-    from pygpibtoolkit.plotter.gpib_plotter import GPIBplotter
 
 
 class Preferences(AbstractPreferences):
@@ -97,7 +94,8 @@
     autodisplay = BoolItem(
         default=True,
         name="Auto display",
-        description="Automatically display a new plot as soon as it is received",
+        description=(
+            "Automatically display a new plot as soon as it is received"),
         group="Misc")
 
 
@@ -151,7 +149,8 @@
         self._plots_list = QtCore.QStringListModel()
         self.plotsView.setModel(self._plots_list)
         self.plotsView.activated.connect(self.currentPlotChanged)
-        self.plotsView.selectionModel().currentChanged.connect(self.currentPlotChanged)
+        self.plotsView.selectionModel().currentChanged.connect(
+            self.currentPlotChanged)
         self.setReceivingLed()
 
     def currentPlotChanged(self, index, old_index=None):
@@ -170,8 +169,8 @@
         self.close()
 
     def closeEvent(self, event):
+        # if self.promptForSave():
         if 1:
-        #if self.promptForSave():
             self._prefs._pos = self.pos()
             self._prefs._size = self.size()
             self._prefs._appState = self.saveState()
@@ -193,7 +192,6 @@
     def openFiles(self, filenames):
         ok = False
         for filename in filenames:
-            print('FNAE=', filename)
             if os.path.exists(filename):
                 data = open(filename).read()
                 name = os.path.basename(filename)
@@ -260,9 +258,10 @@
     def initializeGPIB(self):
         self._online = False
         try:
-            self.gpib_plotter = QGPIBplotter(device=self._prefs.device,
-                                             address=self._prefs.address,
-                                             )
+            self.gpib_plotter = GPIBplotter(
+                device=self._prefs.device,
+                address=self._prefs.address,
+            )
             self.captureThread = GPIBReceiver(self.gpib_plotter)
             self.captureThread.plotReceived.connect(self.plotReceived)
             self.captureThread.plotStarted.connect(self.plotStarted)
@@ -278,9 +277,9 @@
                 self.initializeGPIB()
                 if self.gpib_plotter is None:
                     QtWidgets.QMessageBox.critical(
-                        self, self.tr("GPIB error"),
-                        self.tr("<b>Unable to initialize GPIB connection</b>."
-                                "<br>Please check your GPIB dongle and settings."))
+                        self, "GPIB error",
+                        "<b>Unable to initialize GPIB connection</b>."
+                        "<br>Please check your GPIB dongle and settings.")
                     self._online = False
                     self.setCaptureLed()
                     return
@@ -308,57 +307,37 @@
         self.receivingButton.setIcon(icn)
 
 
-class QGPIBplotter(GPIBplotter):
-    def __init__(self, device="/dev/ttyUSB0", baudrate=115200, timeout=0.1,
-                 address=5):
-        super().__init__(device, baudrate, timeout, address)
-        self.emitter = None
-
-    def plotStarted(self):
-        if self.emitter:
-            self.emitter.emit(SIGNAL('plotStarted()'))
-            # self.emitter.msleep(1)
-
 
 class GPIBReceiver(QtCore.QThread):
+    plotStarted = pyqtSignal()
+    plotReceived = pyqtSignal(int)
+
     def __init__(self, cnx, parent=None):
         super().__init__(parent)
         self.gpibplotter = cnx
-        self.gpibplotter.emitter = self
+        self.gpibplotter.plot_started_cb = self.plotStarted.emit
 
-        self._cancelmutex = QtCore.QMutex()
         self._cancel = False
         # self._nreceived = 0
         self._plotsmutex = QtCore.QMutex()
         self._plots = []
-        self._startstopmutex = QtCore.QMutex()
-        self._startstop = QtCore.QWaitCondition()
         self._capturing = False
 
     def cancel(self):
-        self._cancelmutex.lock()
         self._cancel = True
-        self._cancelmutex.unlock()
 
     def startCapture(self):
-        self._startstop.wakeOne()
+        self._capturing = True
 
     def stopCapture(self):
-        self._startstopmutex.lock()
         self._capturing = False
-        self._startstopmutex.unlock()
 
     def run(self):
-        while 1:
-            self._cancelmutex.lock()
-            if self._cancel:
-                return
-            self._cancelmutex.unlock()
-            self._startstopmutex.lock()
+        while not self._cancel:
             if not self._capturing:
-                self._startstop.wait(self._startstopmutex)
-                self._capturing = True
-            self._startstopmutex.unlock()
+                self.msleep(100)
+                continue
+
             plot = self.gpibplotter.load_plot(wait_timeout=0.1)
             timestamp = time.time()
             if plot:
@@ -366,7 +345,8 @@
                 self._plots.append((plot, timestamp))
                 n = len(self._plots)
                 self._plotsmutex.unlock()
-                self.emit(SIGNAL('plotReceived(int)'), n-1)
+
+                self.plotReceived.emit(n - 1)
             self.msleep(10)
 
     def getPlot(self, num):
@@ -378,6 +358,8 @@
 
 
 def main():
+    global GPIBplotter
+
     import optparse
     opt = optparse.OptionParser(
         'A simple PyQt4 HP7470A GPIB plotter emulator for USB-GPIB bundle '
@@ -393,6 +375,8 @@
                    help="Verbose mode",)
 
     options, argv = opt.parse_args(sys.argv)
+    if options.mockup:
+        from pygpibtoolkit.plotter.gpib_plotter_mockup import GPIBplotter
 
     a = QtWidgets.QApplication(argv)
     w = QtHPGLPlotter()