PendCon

       A digital linear controller including

      encoder pulse counting and A/D and

      D/A conversion










PendCon offers a microprocessor as controller which has two A/D and one D/A converter. To make changes of the controller, an external PC is needed. There are three possibilities to implement these changes:

• There is prepared small user interface where the students can set the four parameters of a PID controller and the set value.

• The  (linear) controller is written in discrete form with matrices Ad, Bd, Cd, Dd. The students have to compute these matrices in advance, normally with suitable software assistance. These matrices are then saved in an ASCII file which can be transferred to the micropocessor.

• They have to program the controller algorithm in C. This requires a C compiler and is possible with a freeware compiler. The compiling and linking procedure is prepared. By this way, the experiment about control theory is to some extend also an experiment about the programming of microprocessors

Other important features of this experiment are:

• The controller accepts as input a voltage (coming from a tacho, e.g.) or pulses coming from an encoder. Two inputs of this kind are feasible.

• Additional AD/DA interface. With the first AD/DA interface it is possible to generate a step response of the controller. To use this feature, an computer with suitable real-time software is needed (like the Matlab xPC-Target, e.g.).