Development of a wire identifier and its application to a thermocouple instrumentation system

Any large electrically controlled system (i.e., a nuclear reactor) has an elusive problem of assuring all wires are connected correctly. Improperly connected wiring could cause misleading results, property damage, or even loss of life. 0 e possible method of insuring proper wiring installation in a large system is to provide a means for each sensor in the system to identify itself when interrogated. The identification is accomplished by applying a signal to a sensor wire pair in a control room to which a specially equipped sensor would respond. An interrogator and sensor identifier would allow a user to monitor the system wiring as often as desired establishing some confidence in the system wiring.

This thesis proposes and develops a wire identification system with an acceptable operating frequency range of 1 kHz to 1 MHz for a two foot thermocouple line connecting the interrogator to the specially equipped sensor. Varying the type and increasing the length of the connecting wire between the identifier and the interrogator may further limit this frequency range. The developed identifier system is shown to properly identify specially equipped thermocouple connectors with various cables and the frequency limitations imposed by these cables are analyzed. The identifier, incorporated into the thermocouple system, interferes with the temperature measurement only during wire identification. This thesis may be used as a base for further experimental work required for a viable identifier system.