Computer virtual instruments

Abstract— In this study, a wireless sensor network (WSN) for flexible pH array sensor has been developed by virtual software of National Instrument (NI) Laboratory Virtual Instrument Engineering Workbench (LabVIEW). The measurement data were received from measurement node and sent to a gateway connecting with computer through WSN. The WSN has been combined successfully with flexible pH array sensor. And the sensitivity and linearity of the flexible pH array sensor received through WSN are 53.39 mV/pH and 0.990 in pH concentrations between pHl and pH13 at room temperate (25 C), respectively. Therefore, the developed WSN can be applied to the flexible pH array sensor practically. 

The input could be from a PC (personal computer), as in word processing, but could equally well be from an instrument the output could be to a video screen, a printer, or to the same or another instrument (Figure 42.9). All these functions are organized by the central processor in so-called real time, i.e., virtually immediately. 

The proliferation of sophisticated instruments which are capable of rapidly producing vast amounts of data, coupled with the virtually universal availability of powerful but inexpensive computers, has caused the field of chemometrics to evolve from an esoteric specialty at the perhiphery of Analytical Chemistry to a required core competency. 

The maintenance of analytical instrumentation requires trained personnel and is a time-consuming task (39,40). An additional problem is the necessity of frequently checking the calibration of the analysis instrumentation and recalibrating if required. Stand-alone data gathering instrumentation, once common in pilot plants, has been virtually replaced in all but the simplest pilot plants by a data gathering computer, usually used for process control as well. 

It is interesting to consider hardness as an example of how mechanical tests for rubber have, or have not developed. Firstly, despite the very imprecise relationship with modulus and the lack of any fundamental significance, hardness measurements have continued to be used and even now new ones are being introduced. The far more sensible method of measuring force to produce a given deformation, which would also allow stress relaxation to be conveniently measured, has not been adopted. However, the instrumentation has been updated so that the old measure can be made with electrical transducers and fed directly to a computer. On the other hand, perhaps the fact that hardness is a non-destructive method that can be applied to virtually any product is justification that it should thrive. 

Physics-based synthesis can provide extremely high quality and expressivity in a very compact algorithm. Such computational models can provide extremely low bit rates at very high quality levels for certain sounds. In addition to data compression applications, such models can also provide a foundation for the future evolution of musical instruments, moving it from the real world of wood and metal into the virtual world where formerly impossible modifications are easily tried out. 

The data reduction hardware is based on a Hewlett-Packard 9825A desk top computer. It is supported by one megabyte of flexible disk storage, a printer/plotter and the necessary interface equipment for on-line LSC data collection. Reliability was a prime factor when the hardware was chosen. The LSC(s) and data system run virtually unattended, 24 hours a day, 365 days a year. Samples are typically counted for two minutes each plus one minute for the external standard. Therefore, data from the four counters are received by the HP9825A at an average interval of 45 seconds. With such a demand on the system, computers require good service support, more so than other instruments. Since installation in May, 1977, there have been less than two work days of cumulative downtime. 

Results of on-line, real-time instrumental analyses are posted directly to the database, with or without processing, as soon as the instrument presents the analytical data. All results are available for review and validation immediately after being posted -a feature critical to effective laboratory management. Data is acquired from laboratory instrumentation of virtually any manufacturer or function. Instruments are interfaced to the computer via analog to digital conversion, RS-232C, current loop, IEEE-4888, binary coded decimal (BCD) or bit parallel techniques. 

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