doc: add some infos

- add some infos in doc
- add count limit prompt in query step

legacy/src/lcr_connector/__init__.py

@@ -149,8 +149,13 @@ class App:
             App.QuerySortPriority
         ).to_response_priority()
 
+        print("How may result are you expected?")
+        count_limit = self.__accept_count_value()
+
         # build request and ask resolver
-        request = Request(device_kind, target_value, tolerance, response_priority, 100)
+        request = Request(
+            device_kind, target_value, tolerance, response_priority, count_limit
+        )
         response = self.__resolver.resolve(request)
 
         # use page viewer to show result
@@ -217,10 +222,33 @@ class App:
             except ValueError:
                 print("Unknown command, please try again.")
 
+    def __accept_count_value(self) -> int:
+        MAX_COUNT: int = 50
+
+        while True:
+            self.__show_prompt_arrow()
+            words = input()
+            if words == "":
+                continue
+
+            try:
+                value = int(words)
+            except ValueError:
+                print("Wrong value, please try again.")
+                continue
+
+            if value > MAX_COUNT or value <= 0:
+                print("Wrong value, please try again.")
+            else:
+                return value
+
     def __accept_device_value(self) -> float:
         while True:
             self.__show_prompt_arrow()
             words = input()
+            if words == "":
+                continue
+
             value = self.__parse_human_readable_value(words)
             if value is None:
                 print("Wrong value, please try again.")
@@ -231,6 +259,8 @@ class App:
         while True:
             self.__show_prompt_arrow()
             words = input()
+            if words == "":
+                continue
 
             if words.endswith("%"):
                 value = self.__parse_plain_float(