High voltage isolation of thermocouples for ion plating

摘要

Instrumentation has been developed to isolate part thermocouples from ground by up to 10.6 kV during ion plating. A fiber-optic link provides signal isolation and errors of better than +or-0.5% of full scale (485 degrees C with type-K thermocouples). Cold-junction compensation and signal gain are provided. A computer interface to the analog output is connected to a thermocouple linearizer, maximum temperature alarm, and current-loop converter. A digital panel meter displays the temperature.