Modify Monitored Item function and Deadband Monitor in the client side

opcua/client/ua_client.py

@@ -477,3 +477,14 @@ class UaClient(object):
         self.logger.debug(response)
         response.ResponseHeader.ServiceResult.check()
         return response.Results
+
+
+def modify_monitored_item_low(self, params):
+    self.logger.info("modify_monitored_items")
+    request = ua.ModifyMonitoredItemsRequest()
+    request.Parameters = params
+    data = self._uasocket.send_request(request)
+    response = ua.ModifyMonitoredItemsResponse.from_binary(data)
+    self.logger.debug(response)
+    response.ResponseHeader.ServiceResult.check()
+    return response.Results

opcua/common/subscription.py

@@ -272,4 +272,46 @@ class Subscription(object):
                     del(self._monitoreditems_map[k])
                     return
 
+    def modify_monitored_item(self, handle, new_samp_time, new_queuesize=0, mod_filter=None):
+        """
+        Modify a monitored item.
+        :param handle: Handle returned when originally subscribing
+        :param new_samp_time: New wanted sample time
+        :param new_queuesize: New wanted queuesize, default is 0
+        :param mod_filter: New wanted filter, default is None
+        :return: Return a Modify Monitored Item Result
+        """
+        modif_item = ua.MonitoredItemModifyRequest()
+        modif_item.MonitoredItemId = handle
+        modif_item.RequestedParameters = self._modify_monitored_item_request(new_queuesize, new_samp_time, mod_filter)
+        params = ua.ModifyMonitoredItemsParameters()
+        params.SubscriptionId = self.subscription_id
+        params.ItemsToModify.append(modif_item)
+        results = self.server.modify_monitored_items(params)
+        return results
+
+    def _modify_monitored_item_request(self, new_queuesize, new_samp_time, mod_filter):
+        req_params = ua.MonitoringParameters()
+        with self._lock:
+            req_params.ClientHandle = self._client_handle
+        req_params.QueueSize = new_queuesize
+        req_params.Filter = mod_filter
+        req_params.SamplingInterval = new_samp_time
+        return req_params
+
+    def deadband_monitor(self, var, deadband_val, deadbandtype=1, queuesize=0, attr=ua.AttributeIds.Value):
+        """
+        Function to create a subscription with a Deadband Value.
+        Default deadband value type is absolute.
+        Return a handle which can be used to unsubscribe
+        :param var: Variable to which you want to subscribe
+        :param deadband_val: Absolute float value
+        :param deadbandtype: Default value is 1 (absolute), change to 2 for percentage deadband
+        :param queuesize: Wanted queue size, default is 1
+        """
+        deadband_filter = ua.DataChangeFilter()
+        deadband_filter.Trigger = DataChangeTrigger(1)  # send notification when status or value change
+        deadband_filter.DeadbandType = deadbandtype
+        deadband_filter.DeadbandValue = deadband_val  # absolute float value or from 0 to 100 for percentage deadband
+        return self._subscribe(var, attr, deadband_filter, queuesize)