Computer-Controlled Transducer Systems: the "Unspecia1ized" Approach to Component Testing

Several computer-controlled test stands had been designed and built to monitor and contral life and performance tests on most of the control components which are used in major laundry appliances today. In the process, some of the problems associated with using a real-time process control computer for approval testing were solved while still taking full advantage of the computer´s inherent capability to perform complex logical operations quickly and effectively. Most of the computer-controlled component test stands were designed specifically for testing components used on the clothes dryer, but the concept of designing a generalized system of control hardware to interface with the computer is applicable to other products. The resulting test stands, therefore, can be used to test automatic washer timers, solenoids, water valves, and switches as well as the relays, switches, and gas valves commonly used on the dryer. In designing the test stands the functions performed by the various components were identified, and components requiring similar control hardware were grouped together. From this grouping it was apparent that only three different types of computer-controlled test stands had to be constructed, one test stand to control thermally actuated components, one to control impulse or step actuated components, and one to test rotary actuated components. The problems associated with obtaining and conditioning the analog and digital signals being transmitted to the computer, and the means by which low-level control signals from the computer are used to control the functioning of the test stand are discussed.