fix: cannot pickle real devices

Solution: use plotting as inner process

Python_script/MeasurementPlot.py

@@ -161,17 +161,19 @@ class MeasurementPlot:
         except queue.Full:
             pass
 
-    def drawing_loop(self):
+    def drawing_loop(self, stop_measurement_event):
+        # turn interactive plotting (back) on (is deactivated by starting the process)
+        plt.ion()
         while True:
             data_frame, pdf_name, stop_drawing = self.data_queue.get()
             if stop_drawing:
                 return
             try:
-                if not process_sync.stop_measurement.is_set():
+                if not stop_measurement_event.is_set():
                     self.draw_in_this_thread(data_frame, pdf_name='')
             except Exception as e:
                 # Don't exit here. Always drain the data queue so the program can terminate correctly
-                process_sync.stop_measurement.set()
+                stop_measurement_event.set()
 
     def draw_in_this_thread(self, data_frame, pdf_name=''):
         timestamps = data_frame.TIMESTAMP

Python_script/prototype.py

@@ -177,17 +177,13 @@ class Measurements:
         """
         process_sync.stop_measurement.clear()
         ctx = mp.get_context('spawn')
-        measurement_process = ctx.Process(target=self.perform_single_measurement_impl,
-                                          args=(output, target_temp, target_hum, soaking_time, n_stable_reads,
-                                                process_sync.stop_measurement))
-        measurement_process.start()
-        # turn interactive plotting (back) on (is deactivated by starting the process)
-        plt.ion()
-        self.measurement_plot.drawing_loop()
-        measurement_process.join()
+        plot_process = ctx.Process(target=self.measurement_plot.drawing_loop,
+                                   args=(process_sync.stop_measurement,))
+        plot_process.start()
+        self.perform_single_measurement_impl(output, target_temp, target_hum, soaking_time, n_stable_reads)
+        plot_process.join()
 
-    def perform_single_measurement_impl(self, output, target_temp, target_hum, soaking_time, n_stable_reads,
-                                        stop_measurement):
+    def perform_single_measurement_impl(self, output, target_temp, target_hum, soaking_time, n_stable_reads):
 
 
         with open(output, mode='w', newline='') as csv_file:
@@ -219,7 +215,7 @@ class Measurements:
                 dut_signal_queues = [[], []]
 
                 while True:
-                    if stop_measurement.is_set():
+                    if process_sync.stop_measurement.is_set():
                         do_another_measurement = False
                         break
                     
@@ -282,7 +278,7 @@ class Measurements:
                 all_measurements_stable = True
 
                 for i in range(0, n_stable_reads):
-                    if stop_measurement.is_set():
+                    if process_sync.stop_measurement.is_set():
                         all_measurements_stable = False #not enough stable reads yet
                         do_another_measurement =  False
                         break