Based Transmitters

Microprocessor-Based Transmitters The cost of microprocessor technology has declined to the point where it is economically feasible to incorporate a microprocessor into each transmitter. Such microprocessor-based transmitters are often referred to as smart transmitters. As opposed to conventional or dumb transmitters, the smart transmitters offer the following capabilities  

They check on the internal electronics, such as verifying that the voltage levels of internal power supplies are within specifications. 

They check on environmental conditions within the instruments, such as verifying that the case temperature is within specifications. 

They perform compensation of the measured value for conditions within the instrument, such as compensating the output of a pressure transmitter for the temperature within the transmitter. Smart transmitters are much less affected by temperature and pressure variations than are conventional transmitters. 

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One of the earliest methods of mass flow determination was to install two separate sensors one to measure the volumetric flow, and the other to detect the density of the flowing stream. On the basis of these two inputs, a microprocessor-based transmitter can measure mass flow. A further improvement occurred when the density and volumetric flow sensors were combined in a single package (Figure 3.75). These units are composed of either a Doppler ultrasonic flowmeter or a magnetic flowmeter and a gamma radiation-... 

A wireless digital data-transmission scheme developed with RF-based transmitter (Tx) and receiver (Rx) modules for a 16-electrode EIT. 

FPL devices have very limited functionality. Hence, the implementation of an FPL device involves highly repetitive, clearly defined tasks, which minimize the potential for undetected systematic errors. An approach to minimize systematic errors within FPL devices, such as PE-based transmitters, should take into account all of the following ... 

Limited variability software for all application programming, unless fixed variability programming was available (e.g., PE based transmitters, PE based operator consoles). 

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