A motor controller receives commands from multiple command sources, the commands having different types, and dynamically allocates an ownership of each command type to a particular command source based on the commands received. In one embodiment, the allocation is according to the first command source to request the command type when there is no other ownership of the command type. A masking table provides the ability to lock out any particular command type from a command source regardless of the ownership. Each command source receives a unique address from a connector system connecting it to the motor controller and, when first connected, responds to a polling by the motor controller with its address and control source type permitting multiple control sources to be automatically configured and accommodated by the motor controller.

A digital controlled inverter (100) for inverting an input signal to an alternating current signal having a clock generator (104) for generating a high frequency clock timing signal and a latch (106) for controlling the passage of the clock timing signal to a power stage (102). The power stage (102), which provides a low distortion alternating current signal, is controlled by the latch (106). A control loop (108) is provided for sensing and converting the alternating current signal to a command signal. The command signal controls the state of the latch (106). The latch (106) is reset at the rate of the clock timing signal and updated with the command signal to provide pulse-to-pulse regulation of the alternating current signal. The inverter (100) comprises a transient response to variations in load proportional to the clock timing signal. In a preferred embodiment, the latch (106) functions as a switch for controlling the power output stage (102). The control loop (108) serves to provide the command signal to operate the latch (106). The alternating current signal is rectified and converted to a digital word and then compared to a reference digital word in a digital comparator (138) to provide the command signal to the latch (106).

A digital controlled converter (100) for converting an input signal to a direct current signal having a clock generator (104) for generating a high frequency clock timing signal and a driver circuit (106) for controlling the passage of the high frequency clock timing signal within the converter (100). A power output stage (102) which provides an output signal is controlled by the driver circuit (106). A control loop (108) is provided for sensing and converting the output signal to a command signal. A latch (128) is utilized for latching the command signal and for controlling the state of the driver circuit (106). The latch (128) is reset at the rate of the high frequency clock timing signal and updated with the command signal to provide incremental correction to the output signal. The converter (100) comprises a transient response to variations in load proportional to the high frequency clock timing signal. In a preferred embodiment, the driver circuit (106) functions as a switch for controlling the power output stage (102). The control loop ( 108) serves to provide the command signal to operate the latch (128). A comparator (138) in the control loop compares the d.c. output signal with an analog reference signal to generate the command signal. In an alternative embodiment, the d.c. output signal is converted to a digital signal and compared to a reference digital word in a digital comparator (292) to provide the command signal.

An optical system driving device is provided. This optical system driving device includes a driving unit for driving an optical system, and a controller for controlling the driving unit so as to create an easement interval for temporarily easing the acceleration during an acceleration period. The optical system reaches a predetermined running velocity at the end of the acceleration period.

An apparatus for controlling a star wheel for precise positioning of specimen containers in circumferentially successive segments of the star wheel. The apparatus includes at least two sensor arrays, each including a transmitter and receiver, which are angularly offset from one another in the plane of rotation of the star wheel and face end surfaces of segmental vanes of the star wheel. Each time the star wheel reaches a defined angular position, one of the sensor arrays responds, and the output signal of this sensor array, via a control circuit, triggers a drive motor for the star wheel such that its rotational speed is reduced, and the output signal of the other sensor array, when the same segment moves past it, stops the motor. With this kind of two-stage triggering of the motor, the inertia of such a star wheel in its rotation is taken into account, so that the star wheel is controllable exactly in such a way that the specimen containers come to a stop successively and with high precision at the desired stopping position, where one or more processing steps, such as a measurement of luminescence, can be performed. By scanning the star wheel with the two sensor arrays directly at its circumference, additional components such as control disks, which are an additional source of error and reduce the precision, can be dispensed with.