Electromechanical drive unit

The prevalent design is a microprocessor-controlled torque rheometer. The system consists of two basic units an electromechanical drive unit and a microprocessor unit. The basic system is shown in Figure 7. 

Hydraulic-drive samplers are also available, but cost factors tend to be substantially greater than electromechanical units. Recent use of hydraiilic-drive systems has diminished with the availability of increased strength and durabihty electric-motor linear-drive units capable of reliable operation in high-capacity applications. 

The rotational actuation, which is typically provided by a conventional, low-cost spindle motor, also removes the requirement of external, pressure-driven pumps and their associated microfluidic interconnects and chip-to-world interfacing. Moreover, the modular nature of the LoaD platform completely separates the electromechanical driving instrumentation and the conventional optical readout units from the liquid sample and reagents under test the sample and/or reagents are exclusively handled by the microstructured, typically disposable test disc. These features are particularly beneficial for biological applications since the potentially hazardous samples can be processed in an encapsulated system, thus minimizing the risk of crosscontamination and carry-over. 

The outputs from the processing unit will typically interface with electromechanical contactors, relays, variable speed drives, solenoid-operated pneumatic valves, and indicating light bulbs. 

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