By PURPLELEC | 15 September 2023 | 0 Comments
How the data acquisition card works
When the data acquisition card is used, the data acquisition system is placed at the monitored equipment, and the voltage or current signal of the equipment is sampled and held through the sensor, and sent to the A/D converter to become a digital signal, and then the signal is sent to in FIFO.
When the data stored in the FIFO reaches a certain amount, the ARM7 reads it from the FIFO and then sends it to the host computer through the ARM7's Ethernet interface or RS232. Considering that there may be many devices to be monitored, multiple acquisition channels are designed. They pass through the analog switch and then enter the A/D converter.
CPLD is the control core of the entire system. It controls the switching of the acquisition channel, the start/stop of the A/D converter, the storage address generator of the converted data in the FIFO, and generates an interrupt request to notify ARM7 to read and store it in the FIFO. data, etc.
The running data is sent to the PC, and the data is analyzed through specific software running on the PC to determine the status of the current operating equipment and then take corresponding measures. Currently commonly used data acquisition devices mostly use a single-task sequential mechanism in their system software design.
This leads to the problem of poor system security. This is not allowed for data acquisition devices with high stability and real-time requirements, so it is necessary to introduce an embedded operating system.
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