handle modbus errors

dbus-solax-x1-pvinverter.py

@@ -68,7 +68,7 @@ def __init__(self, servicename, deviceinstance, paths, productname='Solax X1', c
       else:
         self._dbusservice.add_path(
           path, settings['initial'], gettextcallback=settings['textformat'], writeable=True, onchangecallback=self._handlechangedvalue)
-
+    self._updateRunning = False
     # last update
     self._lastUpdate = 0
     self._lastCloudUpdate = 0
@@ -286,6 +286,9 @@ def _predictACPowerValue(self, lastUpdate, lastValue, lastValueChangePercSecond)
     return lastValue*((1+((time.time() - lastUpdate)*lastValueChangePercSecond)))  
 
   def _update(self):
+    if (self._updateRunning):
+      return True
+    self._updateRunning = True
     logging.info("Running _uppdate")
     config = self._getConfig()
     try:  
@@ -411,7 +414,8 @@ def _update(self):
       logging.info("_update failed, modbus not ready yet")
     except Exception as e:
       logging.critical('Error at %s', '_update', exc_info=e)
-
+
+    self._updateRunning = False
     # return true, otherwise add_timeout will be removed from GObject - see docs http://library.isr.ist.utl.pt/docs/pygtk2reference/gobject-functions.html#function-gobject--timeout-add
     return True