Reworked Tutorial 3

Signed-off-by: Lukas Bromig <lukas.bromig@tum.de>

examples/Tutorial_3_Using_The_Data_Handler.py

@@ -1,10 +1,32 @@
-# You can use this code editor like a regular scripting environment.
-# If you require specific python packages for your script, you can import them here.
-# Note: Packages you want to import must be specified in the dockerfiles requirements.txt!
+"""
+TUTORIAL 3: Using the Data Handler
+---------------------------------------------
+3.1 The data handler can be used without writing a script. Go to the data handler tab and setup a database. Influx
+    databases are supported. The overview will show you whether a connection has been established between the SiLA 2
+    Manager and the specified database. Depending on the security settings of your database, supplying a username or
+    password may not be necessary.
 
-import time
+3.2 You can link a database to a specific SiLA service. Click on the link button and select the desired database. You
+    can unlink a database by selecting the empty option [] in the drop-down menu.
 
+3.3 There are several levels of customization. Expand the Service tree and activate the SiLA Features you want the data-
+    acquisition to be active for. Selecting "Data Transfer" on the top level will automatically activate all features.
+    Start de-selecting.
 
-def run(devices):
+3.4 The data handler distinguishes between two types of data: Meta data and process/experimental data. They differ in
+    the time interval they are queried in. Both types have a set default polling interval. However, you may customize
+    the time interval for both of them for each SiLA Command and Property on the lowest level of the tree.
+
+3.5 If a command requires a parameter, you can set the parameter here.
+
+3.6 The data handler is active for the full duration of the experiment and does not stop when the script is finished.
+    It will only stop at the specified time or if the experiment is stopped manually.
+
+Hint 4: If your parameter changes over time, you should exclude the command query from the data handler and add a
+    respective function and command call to your experimental script.
+"""
+
+
+def run(services):
     """ Required to import and instantiate devices """
     return