Requirements for process infrared analyzers

For many applications, laboratory-based analyses may be developed on standard laboratory instruments. While these are not always the most ideal, they do provide a starting 

2 Analyzers for near-line or at-line plant measurements 

Most analyzers incorporate a personal computer (PC) for data acquisition, control, data analysis, presentation/display of results, and communications. Many are integrated via Ethernet-based networks. Two approaches are used either the computer is integrated into the analyzer package, including the visual display and keyboard/control panel (an abbreviated keyboard or a preprogrammed equivalent), or a separate industrial-grade 

Designing a process analyzer does not stop at the enclosure and the internal components. The electronics, the spectrometer and all associated optics must be made to be insensitive to the operating environment. This is particularly important for IR instruments that feature sensitive optics and also high-temperature energy sources. This may be achieved by design, where all components must operate reliably independent of the operating environment of the instrument/analyzer, which can include wide variations in humidity and temperature, and the presence of vibration, over a broad range of frequencies. 

Most on-line analyzers are installed as permanent fixtures. Bearing this in mind, environmental issues associated with temperature and vibration become more critical, and the requirement for conformance to safety standards may be enforced by the need for system certification. The latter requires an assessment of the working environment, and the potential for fire and/or explosion hazard, relative to the anticipated presence of flammable vapors or gases. Safety hazard and local electrical design code compliance, which includes CE Mark for Europe, Canadian Standards Association (CSA) for Canada, 

One important distinction is a logical separation between the terms instrument and analyzer. An instrument is totally open-ended and flexible in terms of sampling and operation, and typically generates data that 

2 Analyzers for Near-line or At-line Plant Measurements 

The requirement for simplicity of sampling and analyzer operation is even more essential within a plant environment. Sampling must be highly reproducible and require only a minimum of operator skill. One must not second-guess an operator when designing either the sample-analyzer interface or the nser interface of the analyzer. Keystrokes for any operation must be kept to a minimum, and where practical, devices such 

Most on-line analyzers are installed as permanent fixtures. Bearing this in mind, environmental issues associated with temperature and vibration become more critical, and the reqnirement for conformance to 

System installation in a permanent location may require a sample conditioning system featuring some degree of automation, such as automatic cleaning (the system illustrated above features such a system) and outlier sample collection and the need to interface to an existing control system process computer. The latter may require that the system operates with a standardized communications protocol, such as Modbus, for the chemical industry. Certain specialized industries use different protocols, such as the semiconductor industry, which uses SECS and SEC-11 protocols. A standardized approach designated the Universal Fieldbus is another method/protocol for process analyzers which is being supported by certain hardware manufacturers. 

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