diff --git a/swissmx.py b/swissmx.py
index 4c45cfa..c24b6c2 100755
--- a/swissmx.py
+++ b/swissmx.py
@@ -715,6 +715,7 @@ class WndSwissMx(QMainWindow, Ui_MainWindow):
               _log.debug(f'diff:{k},{v} != {paramSv[k]}')
 
         cam.run(self.cb_new_frame_pv)
+        app._pv_mon_lst.append(cam._pv['pic'])
 
   def cb_new_frame_pv(self, **kwargs):
     try: #pv-monitor-func
@@ -995,11 +996,19 @@ class WndSwissMx(QMainWindow, Ui_MainWindow):
 
     #pv-monitor-func
     #_log.info('modify monitors')
-    #for w in widgets[1:-1]: #ignore last item
-    #  for k,pv in w._motor._pvs.items():
-    #    pv.auto_monitor=False
-    #  for k,pv in w._motor._pvs.items():
-    #    pv.auto_monitor=True
+    app=QApplication.instance()
+    pv_mon_lst=app._pv_mon_lst
+    try:
+      for w in widgets[:-1]: #ignore last item
+        for pv in w._motor._pvs.values():
+          pv_mon_lst.append(pv)
+      #  for k,pv in w._motor._pvs.items():
+      #    pv.auto_monitor=False
+      #  for k,pv in w._motor._pvs.items():
+      #    pv.auto_monitor=True
+    except AttributeError as e:
+      sim=app._args.sim
+      assert(sim&0x10,'assuming simulated motors')
 
   def build_group_collimator(self, toolbox):
     pfx=QApplication.instance()._cfg.value(AppCfg.GBL_DEV_PREFIX)[1]
@@ -2262,6 +2271,11 @@ Author Thierry Zamofing (thierry.zamofing@psi.ch)
     sp.meta['sync_mode']=dt_misc['sync_mode']
     sp.meta['sync_flag']=dt_misc['sync_flag']
 
+    #pv-monitor-func: stop monitors
+    pv_mon_lst=app._pv_mon_lst
+    for pv in pv_mon_lst:
+      pv.auto_monitor=False
+
     with pg.ProgressDialog('Progress', 0, 100) as dlg:
       dlg.setWindowModality(Qt.WindowModal)
       #dlg.setRange(0, 0)
@@ -2325,6 +2339,9 @@ Author Thierry Zamofing (thierry.zamofing@psi.ch)
         comm.gpascii._cb_func=lambda i, sz:self.cb_progress(i, sz, dlg)
 
       if dlg.wasCanceled():
+        # pv-monitor-func: start monitors
+        for pv in pv_mon_lst:
+          pv.auto_monitor=True
         return
       dlg.setLabelText("Homing and get ready");dlg+=5
       sp.homing()  # homing if needed
@@ -2365,6 +2382,9 @@ Author Thierry Zamofing (thierry.zamofing@psi.ch)
             #plt.show(block=True)
 
       shutter.close()
+    # pv-monitor-func: start monitors
+    for pv in pv_mon_lst:
+      pv.auto_monitor=True
 
   def esc_run_steps(self, steps, title, esc_state):
     self._esc_state ="busy"
@@ -4139,6 +4159,9 @@ if __name__=="__main__":
 
     app._args=args
 
+    app._pv_mon_lst=list() #pv-monitor-func: list of all pv that are monitored and that should
+                           # be turned on/off during data collection to avoid (hopefully) segmentation fault
+
     startupWin.set(5, f'load settings')
     app._cfg=cfg=AppCfg()