There are obvious advantages that the instrument based on PXI technology possesses a high speed, a small size and easy expansion, so the hardware structure will use PXI bus technology and relevant products based on the PXI bus. The system concludes PXI-1042 chassis, PXI-8186 Controller, PXI — 6221 multifunction data acquisition card, PXI-4351 high-precision temperature and voltage logger, PXI-6513 digital I/O card, and SC-2345 signal conditioning modules.

Fig. 3 shows the physical structure. PXI-1042 as chassis has 8 slots to comply with PXI and CompactPCI specifications with universal AC power supply. PXI-8186 as embedded controller can greatly improve the system scalability and integration. PXI-6221 multifunction data acquisition card can support two 16-bit analog outputs and has 24 digital I/O, 32-bit counters and digital triggering. PXI-4351 as high-precision temperature and voltage logger includes 8 digital I/O lines (TTL), 16 voltage or 14 thermocouple inputs and autozero and cold-junction compensation and its accuracy can reach 0.12°C for RTDs. PXI-6513 digital I/O card possess optical isolation in banks of 8 channels, 64

sink outputs. This card is a low-cost solution with advanced features for industrial control and manufacturing test applications and it is also a high-reliability industrial feature set. SC-2345 series have connector block and configurable connectors.