266 Interface Module  

The interface modules consist of simple electrical level shifters to comply with the interface electrical  protocol, all logic protocol tasks are performed in the Controller System. A set of different interface  modules , e.g., for RS -422 interfaces, Mil-Bus 1553B topologies exist. The interface module has been  mechanically sized to allow the application of an additional programmable component (FPGA) to support  other interface or bus topologies that have a high  performance demand.  

Flexibility with D edicated  Actuator Frame s 

The biggest  challenge in developing a universal Mechanism Control Electronics results from the high  variety of available motor types, motor characteristics as well as the sensor type for position, velocity or  acceleration sensing.  

In motor amplifier design, EMC fil tering and motor current damping is a function of motor amplifier  topology  (linear vers us PWM  technology), PWM frequency, max imum  motor current amplitude,  and  required damping over frequency. Besides this, the motor characteristics (inductance, coil resist ance,  Back EMF  voltage) and proper dimensioning/shielding have significant influence to the EMC behavior of  the system and therefore also to the behavior of the required filter . 

Although one filter design can fit to a range of motor characteristics, adaptation to significantly different  characteristics will always be necessary.  This is especially the case for low -inductive motor type in highvelocity systems compared to higher inductive motors in low -velocity / high -torque systems.  

The same is valid for the sensors measuring position and velocity  of the mechanical system.  These  sensors follow the operational and accuracy demands of mechanical systems and typically differ from  equipment to equipment.    During the development work it became obvious that one single electrical circuit dedicated and  optimized to one specific motor characteristics can never serve completely different motor topology   and characteristics.    Sensor acquisition electrical circuits within the universal MCE need the flexitility to adapt to sensor  characteristics, sensor type and their required range, resolution and accuracy pending on  mechanism topology.  

In order to maintain the universal MCE approach despite this adaptation need, it has been decided that  specific Actuator Boards, carrying the motor amplifier(s) together with the sensor acquisition cirucits, will  be mandatory for a universal architecture. Therefore, the interface between Core Frame and Actuator  Frame has been designed as an open architecture to ensure compatibili ty to any motor and sensor type.  

Such different Actuator Frames are now characterized by the motor type / electrical parameters and by  the type of sensors used in the mechanism. Once an Actuator Boar d has been developed and qualified  for such a  combination, r e-use of this Actuator Frame design for other mechanisms with the same or a  similar configuration is guarateed due to the control loops being held under software control.  Presently,  Actuator Frames are in design and commissioning for   A. 2-phase Stepper Motor application (range 10- 50 Ω / 10- 100 mH) with Hall  Sensor / Switch /  Potentiometer  sensors   B. 3-phase Brushless -DC Motor application (range 5- 15 Ω / 15-50 mH) with digital serial optical  encoder   Further mechanism characteristics can be adapted by development of the respective Actuator Frames,  the open architecture allows quick response time for any type of mechanism / sensor system.  

Figure 6 shows the concept of different actuator frame s with their standardized electrical and mechanical  interface to the Core Module.