The processing core handles simple data filtering tasks such as pseudo pulse counting, noise suppressed accumulation, and/or baseline correction, then passes the processed filtered data to either a master subprogram for future data sorting, or the UI for display and streaming of raw data to storage media. Acquired data are fed into a processing core for simple digital filtering while the high level UI displays instrumental parameters. The low level UI sends messages to the HAL modules that communicate bi- or unidirectionally with the hardware. There is a master subprogram on top of the high and low levels of the UI that runs the instrument in automatic acquisition mode to facilitate high volume data acquisition for applications such as MS imaging. The unique features enabled by this design include: (1) >1 kHz data acquisition repetition rate for MS imaging with the ability to collect generic, pulsed time-of-flight mass spectra without signal averaging or summing, (2) flexible peripheral device control, (3) real time data processing, and (4) ready implementation of dynamic or data dependent experiments.Įach block in Figure Figure1 1 represents a loop or module inside the software. Pink colored blocks do not interfere with the instrument control sequence. The general communication direction follows from dark to light yellow, then green, and finally cyan. Colors for other blocks are chosen to group them by type. Cyan and green blocks represent actual hardware units and software communication cores, respectively. Dotted lines represent alternative operation modes. Solid lines represent regular operating modes, and dotted lines show alternative modes. Illustration of software concept/structure and hardware connections of the ChiMS data acquisition and control software package. Finally, customized user-designed experiments can be easily written based on several templates included in the ChiMS software. The data acquisition mode generally simulates a digital oscilloscope, but with peripheral devices integrated for control as well as advanced data sorting and processing capabilities. However, the ChiMS software has now evolved so that it is additionally well suited to non-laser based MS imaging and various other experiments in laser physics, physical chemistry, and surface science. 15,16 ChiMS was also designed for transferring large datasets from a digitizer to computer memory at high repetition rate saving data to hard disk at high throughput and automating data processing, imaging and depth profiling experiments. ChiMS was initially designed for a laser-based time-of-flight mass spectrometer optimized for imaging and depth profiling 15–18 and some aspects of the software performance have been described previously. This paper describes a versatile open-source instrument control software platform named ChiMS that was written within LabVIEW for imaging and depth profiling mass spectrometers. However, LabVIEW is actually a compiled programming language that resides on top of the low-level virtual machine (LLVM) compiler which does allow high data transfer rates. Some users consider LabVIEW to be interpreted and therefore limited by data transfer rates. LabVIEW software (National Instruments, Austin, TX) has been widely adopted for data acquisition and control of customized scientific instrumentation, 8,9 including mass spectrometers, 10–13 and many data acquisition programs written in LabVIEW are open source. 5–7 Publically hosted, open-source instrument control software can permit similar advantages, especially given that so many MS imaging configurations are actually ion source modifications on commercial MS analyzers. 1 Open source software has been developed for the analysis of mass spectrometry (MS) datasets, 2–4 including those produced in imaging experiments. Furthermore, community support of open-source software can improve interoperability and flexibility. Cost, frequency of upgrades, and integration with evolving operating systems are among the additional issues that can arise with commercial data acquisition software.įree open-source data acquisition software can lower the cost of owning, maintaining, and operating custom-built scientific instruments. However, commercial software is usually proprietary and often cannot be readily modified for alternate modes of operation without the express permission and cooperation of the instrument vendor. Software also plays an important role in the customization of commercial mass spectrometers as well as in the implementation of entirely “homebuilt” instruments, both of which can be used to prototype novel experimental strategies. The data acquisition and control software that is provided with commercial mass spectrometers generally performs well at the specific modes of operation for which such instruments have been designed.
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