| 摘要 |
A titrating system includes a pulse length modulator for controlling a drive train including a DC drive motor to supply a given dosage of a titrating agent to a specimen. The pulse length modulator is so designed that the drive motor is supplied with DC-current pulses having a constant amplitude, the lengths of the pulses being a function of the start-up characteristic of the drive apparatus. In order to produce the simultaneous dosing of two different titration agents, at least two dosing arrangements and at least two drive trains are provided, thereby affording a joint control-train pair for the alternate selection of the drives. By virtue of the combination of several control-train pairs, a large number of simultaneously selectable pairs of supply devices can be provided. In a preferred embodiment, the pulse length modulator supplies to the electromechanical drive apparatus DC voltage pulses having a generally constant amplitude. |
