Programmable microprocessor controller operating systems

Today s programmable microprocessor controller operating systems are the result of about a half-century of evolution and provide the available repeatability and reliability required on the plant floor. In the past, achieving these objectives meant choosing a vendor-specific operating system and choosing that vendor s entire control system. This can be a... 

Many of the controls are sequential and on-off thus, the control philosophy is particularly amenable to PLC (Programmable Logic Controller), PC (Personal Computer), or Distributive Microprocessor Controls. Proportioning controls can be easily incorporated into such a system. A Graphic Panel Display with digital indicating and recording modes will add clarity for the operators of the plant. 

Distributive controi systems combine some of the most innovative technologies into an interactive network of intelligent microprocessors, application software, and communication networks. The hardware for a DCS includes a host CPU or programmable logic controller (PLC), intelligent field devices (transmitters, controllers, and control valves), remote CPU, and keyboard. This type of system offers the highest level of operator interaction. 

The programmer, also referred to as the controller, operates the sample system and the analyzer. In addition to this, it handles collection and presentation of the chromatographic data. The controller is now a computer that has replaced the microprocessor as well as the original cam timers. Its basic function is to control valve switching for multiple streams and calibration standards in the sample system. For the analyzer, it controls the operation of the sample inject and column switching valves. Multiple streams can be handled with different valve switching times and seqnences. The detector can also be automatically zeroed. 

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