Optically isolated High-Speed data acquisition system for ion mobility spectrometry

Many sensor applications require sensor data transmission from high electrical potential to ground potential. For example, the instrumental setup of ion mobility spectrometers (IMS) can be greatly simplified by operating the ion source at ground potential and the detector at high electrical potential. This operation mode demands the ion current signal to be transmitted electrically isolated from the detector to the data acquisition system. Furthermore, many applications require high sampling rate and high resolution of the data acquisition. Therefore, a novel open-source high-speed data acquisition system is presented that enables optically isolated data acquisition and facilitates a signal-to-noise ratio (SNR) of up to 87.5  dB with an adjustable sampling rate of up to 12.5 MS/s. To minimize the number of communication lines, an analog-digital-converter (ADC) with a serial high-speed interface is used instead of a parallel interface. Thereby, the communication lines can simply be isolated by only two common, low-cost optical network transceivers. In order to increase the SNR of the data acquisition, a commercial system on a chip (SoC) module digitally low-pass filters the ADC data and then reduces its sampling rate. An ethernet with TCP/IP connection is used to retrieve, visualize and save the recorded measurement data. In addition to the optically isolated high-speed data acquisition, the data acquisition system has one trigger pulse input channel and seven configurable pulse output channels, which enable compatibility with further control electronics.