Updating canvas slows down loop. only increment it if new field is set

Takes ca 50-100ms

src/csv_threading.py

@@ -95,15 +95,6 @@ class ExecCSVThread(Thread):
             t = time.time() - t_zero  # get time relative to start of run
             target_t = array[i, 0]  # Target execution time of data point
 
-            # Update figure
-            try:
-                for j in range(4):
-                    avx_lines[j].set_data([t, t], [0, 1])
-                #print("The next line might crash the programm, outcomment if necessary")
-                parent.plot_canvas.draw()  # equivalent to matplotlib.show()
-            except DeviceAccessError as e:
-                ui_print("Failed to update figure: ", e)
-
             if t >= target_t:  # time for this row has come
                 field_vec = array[i, 1:4]  # extract desired field vector
                 ui_print("[{:5.3f}s] B=[{:.1f}, {:.1f}, {:.1f}]\u03BCT for t={:.2f}s".format(t,
@@ -119,11 +110,22 @@ class ExecCSVThread(Thread):
                 logger = controller.pages[ui.ConfigureLogging]  # get object of logging configurator
                 if logger.event_logging:  # data should be logged when test bench is commanded
                     logger.log_datapoint()  # log data
+
+                # Update figure
+                try:
+                    for j in range(4):
+                        avx_lines[j].set_data([t, t], [0, 1])
+                    # print("The next line might crash the programm, outcomment if necessary")
+                    parent.plot_canvas.draw()  # equivalent to matplotlib.show()
+                except DeviceAccessError as e:
+                    ui_print("Failed to update figure: ", e)
+
                 i = i + 1  # next row
 
             elif t <= target_t - delay - 0.02:  # is there enough time to sleep before the next row?
                 time.sleep(delay)  # sleep to give other threads time to run
 
+
         ui_print("Sequence executed, powering down channels.")