Six Channel 16 Bit PXI Acquisition Module Hardware Design

Signal acquisition and processing technology is a key part of the information technology, based on electronics technology, computer technology and bus technology,data acquisition system is the main way to access to outside information. Due to the defects of a single channel, slow transmission speed and bad real-time information detection, traditional data acquisition device have already couldn’t meet the growing needs, such as in chemical and pharmaceutical factories, temperature and humidity are needed to be monitored in real time and accurately in the manufacturing process.With the developments of intergrated circuits, computer technology and bus technology,large-capacity multi-channel synchronous data acquisition, high speed data transfer and real-time display technology have developed rapidly. And it has been more widely used in the field of bio-medical devices, instrumentation and industrial automation equipment.On the basis of six-channel 16-bit PXI acquisition module R&D project, this paper will mainly introduce the hardware design of the acquisition module with six channels.we maily do research on the overall program design, 6-channel synchronous data acquisition, the storage circuit design of continuous recording and scanning modes,digital trigger circuit design.Specific contents of this paper are as follows:1. Signal conditioning circuit, including multi-stage amplifier circuit, vertical offset adjustment circuit and low-pass filter circuit. After conditioning, the magnitude of signal is enough to reach within a reasonable range for ADC acquisition.2. The design of data acquisition and memory control. It used ADC+FPGA architecture in the design, the maximum sampling rate is 250KS/s, the resolution is 16 bits, 6-channel synchronous data acquisition is the key in acquisition circuit design. Memory circuit design introduces the storage circuit design of continuous recording mode and scan mode. Decoding circuit, the gain control of the channel, ADC control, etc are all implemented in the FPGA.3. All-digital trigger circuit design. Taking advantage of the characteristics of first in first out of FIFO memory, combined with the characteristics of digital comparator, we could achieve trigger function by controlling FIFO memory read and write.After debugging and testing, the six-channel data acquisition module reached the design requirements.