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doc/intro.md

 # Introduction
+
+adwin_control is a python project aiming the replacement of analog PID controllers in the lab.
+
+
+## System Description
+
+A `adwin_control.ServoDevice` is a model of the whole ADwin device.
+Each device can control eight servos modeled by `adwin_control.Servo`.
+A `Servo` has an input for the error signal, an aux input and an output for the controlling signal.
+
+TODO System image
+
+## Hardware Configuration
+
+It uses an [ADwin Pro II](https://www.adwin.de/de/produkte/proII.html) rack with the following configuration:
+
+* 1 Pro **CPU T12**
+* 2 **analog inputs** (8 channels, 16bit and ±10V) 
+* 2 **analog outputs** (8 channels, 16bit and ±10V)