Blanco-Claraco José Luis, López-Martínez Javier, Torres-Moreno José Luis, Giménez-Fernández Antonio
Engineering Department, University of Almería, Ctra. de Sacramento s/n, La Cañada 04120, Spain.
Sensors (Basel). 2015 Oct 27;15(10):27374-92. doi: 10.3390/s151027374.
Most experimental fields of science and engineering require the use of data acquisition systems (DAQ), devices in charge of sampling and converting electrical signals into digital data and, typically, performing all of the required signal preconditioning. Since commercial DAQ systems are normally focused on specific types of sensors and actuators, systems engineers may need to employ mutually-incompatible hardware from different manufacturers in applications demanding heterogeneous inputs and outputs, such as small-signal analog inputs, differential quadrature rotatory encoders or variable current outputs. A common undesirable side effect of heterogeneous DAQ hardware is the lack of an accurate synchronization between samples captured by each device. To solve such a problem with low-cost hardware, we present a novel modular DAQ architecture comprising a base board and a set of interchangeable modules. Our main design goal is the ability to sample all sources at predictable, fixed sampling frequencies, with a reduced synchronization mismatch (<1 µs) between heterogeneous signal sources. We present experiments in the field of mechanical engineering, illustrating vibration spectrum analyses from piezoelectric accelerometers and, as a novelty in these kinds of experiments, the spectrum of quadrature encoder signals. Part of the design and software will be publicly released online.
大多数科学与工程实验领域都需要使用数据采集系统（DAQ），这类设备负责对电信号进行采样并将其转换为数字数据，通常还会执行所有必要的信号预处理。由于商业DAQ系统通常专注于特定类型的传感器和执行器，在需要异构输入和输出的应用中，例如小信号模拟输入、差分正交旋转编码器或可变电流输出，系统工程师可能需要采用来自不同制造商的互不兼容的硬件。异构DAQ硬件常见的不良副作用是每个设备采集的样本之间缺乏精确同步。为了用低成本硬件解决此类问题，我们提出了一种新颖的模块化DAQ架构，它由一个基板和一组可互换模块组成。我们的主要设计目标是能够以可预测的固定采样频率对所有源进行采样，使异构信号源之间的同步失配减小（<1微秒）。我们展示了在机械工程领域的实验，说明了来自压电加速度计的振动频谱分析，以及在这类实验中的一个新内容——正交编码器信号的频谱。部分设计和软件将在网上公开发布。
