An updated T-series thermocouple measurement system for high-accuracy temperature measurements of the MMT primary mirror

摘要

Starting in 2009, MMTO began design and installation of a new set of electronics to measure a set of radiallydistributedtype T thermocouples installed after the primary mirror polishing was completed. These thermocouplesare arranged in both single measurement points and as thermopiles for differential temperature sensing. Since thegoal of the primary mirror temperature control system is to minimize mirror seeing and mirror figure errors inducedby temperature variation across the primary mirror, it depends on excellent accuracy from the temperature sensingsystem. The new electronics encompass on-board cold-junction compensation, real-time ITS-90 curve fitting, andEthernet connectivity to the data servers running in the MMTO software infrastructure. We describe the hardwaredesign, system wiring, and software used in this system.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.