Development of multi-channel high-accuracy thermocouple acquisition-board

YUAN Jian-ting, JIANG Zhou-shu, HUANG Guo-hui
(School of Automation, Hangzhou Dianzi University, Hangzhou 310018, China)

Abstract: In order to meet the requirement that industrial field need to measure lots of temperatures, 16-channels high-accuracy thermocouple acquisition-board was developed, the ADμC834 chip made by ADI Corporation was chased as main chip. By using the on-chip 24bit ∑-Δ type A/D, external high-accuracy reference-voltage module, combined with the rational design of signal conditioning circuit and MCU program, the high-accuracy acquisition was realized. Multi-channel conversion chip could switch 16 channels. To realize cold junction compensation, thermal resistance PT100 was used to acquire the cold-side temperature. The experiments show that the acquisition-board has the merits of multi-channel switch, high-accuracy, low cost, wide metrical range of temperature, simple operation, etc..
Key words: ADμC834; thermocouple; 16-channels; cold junction compensation; high-accuracy