R&D And Application Of Characterization System For Three-isolated Pressure Transmitter

In the present period, the high accuracy smart temperature transmitters and differential pressure transmitters are nearly foreign brands. The reason is that digital smart transmitters abroad adopt advanced inspection technology. This kind of technology can eliminate bad effect from severe environments such as humidity, dust for measure. Furthermore, it can make the accuracy as 0.05%, measure ratio to 1:400 and stability& longevity can remain more five years. The communication protocols of those transmitters are more perfect and acquire security certificate. Compared with domestic transmitter,the overall performance of foreign Transmitter are able to content with mostly industry field measurement and control requirements. Consequently, foreign brand transmitters can get the widespread concern and using from domestic customers. To meet the requirements of domestic customers and extend the sales volume of our products in domestic market, Silian group organized R&D experts to make technological breakthrough,then start R&D of three-Isolation pressure transmitter product. So, we describe R&D and application of three-Isolation pressure transmitter regarding automatic characterization system.In this paper, we study the purpose of automatic characterization of temperature system is solve three-isolation pressure transmitters have zero drift and temperature drift and nonlinear problems. Therefore we start with the overall planning of automatic temperature compensation system, elaborate the workflow of the automatic temperature compensation system software which are developed based on Microsoft Visual C + + 6.0 compiler environment This paper focuses on the GPIB bus, RS232 bus and PCI bus communication protocols, and the software control and operate the hardware of system by bus protocol applications. On this basis, we can carry out calibrating sampling and data storage in the temperature compensation range of the transmitter. After characterized, the system software will put the raw sampling data into the polynomial arithmetic which based on the least square method to do linear correction calculation, and storage the calculated coefficient into the system database, meanwhile writing the coefficient into the E2PROM of control board of the characterization transmitter. The whole characterization processes is in a constant temperature, sealed environment. Therefore, this paper elaborates the structure of the fixtures in the characterization system, and the principle how to carry out bus switch and gas path selection by the external hardware.After more than a year of exploration and research, and a lot of experiments and test, the three-Isolation pressure transmitter automatic characterization system can meet the requirements of production customers and applied in the transmitter temperature compensation field of Silian group. The transmitters characterized eliminate zero drifting, temperature drifting and nonlinear issues which improve the stability, reliability and measurement accuracy.