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There is a logical reason why it is said that the Rosemount series of fieldbus transmitters have the capability to reduce the overall cost of the system. In the 4–20mA communication mode, Rosemount series transmitters can measure only one physical variable; if this measured value is to be converted into the data required for control, additional instruments are needed. For example, when measuring steam flow with temperature and pressure compensation, 3 Rosemount series transmitters are required to measure temperature, pressure, and pressure difference (flow) respectively. In a fieldbus control system, only one Rosemount series fieldbus transmitter is required. This not only **simplifies** the system structure, but also reduces the overall cost of the system; furthermore, it lowers the expenses associated with system installation and debugging. Fully Digital Nature In the previous sections, we introduced several key features of Rosemount fieldbus transmitters; in this section, we will devote more space to discussing the fully digital nature of these Rosemount fieldbus transmitters. What does full digitization of Rosemount fieldbus transmitters mean? Rosemount fieldbus transmitters utilize fieldbuses as a digital communication network that extends from the control room to the production site, replacing the previous point-to-point analog signal transmission with serial digital transmission over a single line for multiple points. Rosemount smart transmitters contain both digital and analog circuits. In Rosemount fieldbus transmitters, both the sensor circuit and the converter circuit are digital. Therefore, the fully digital nature of Rosemount fieldbus transmitters results in a simpler structure for these transmitters, and they offer higher resolution, faster measurement speeds, and better stability compared to Rosemount intelligent transmitters. Interoperability: The fieldbus communication method used in Rosemount transmitters is gradually being standardized on an international level. By staying aligned with these international standards, it is possible to ensure good interoperability among Rosemount transmitters that use fieldbus technology. So what is interoperability? The so-called interoperability of fieldbus-type Rosemount transmitters refers to the ability of devices from different manufacturers to communicate with each other and to perform their functions in a multi-manufacturer environment. The interoperability of Fieldbus-type Rosemount transmitters enables devices from different manufacturers to be used together. In terms of the composition of control systems, any Fieldbus devices that comply with international Fieldbus communication standards can exchange information with each other, regardless of the manufacturer. In this way, users need not choose Rosemount fieldbus transducer devices around a particular instrumentation company. Moreover, the fieldbus-based Rosemount transmitters increase the flexibility in constructing control systems, allowing users to create systems that meet their requirements at the best performance/performance ratio. High-precision performance features: Rosemount transmitters, which are fieldbus-type transmitters, possess many excellent features. Here we will introduce the high-precision characteristic of one of these fieldbus-type Rosemount transmitters. In intelligent Rosemount transmitters, the sensor does not directly convert the signal to digital form; instead, the pressure difference acts on a diaphragm, causing it to move and thereby changing the capacitance or resistance. This results in an output voltage, which is then converted into a digital signal through the transmitter’s analog-to-digital (A/D) conversion before being sent to the microprocessor. In fact, there are also some intelligent Rosemount transmitters in which the displacement of the differential pressure diaphragm is directly converted into a frequency signal, without an A/D converter. However, D/A converters still exist in order to retain 4–20mA analog signals. Therefore, in intelligent Rosemount transmitters, the accuracy of signal transmission decreases due to repeated A/D and D/A conversions. However, fieldbus-type Rosemount transmitters do not have A/D and D/A conversion circuits, so there are no conversion errors associated with A/D and D/A conversions; as a result, the accuracy of signal transmission is improved. Therefore, fieldbus-type Rosemount transmitters offer higher precision compared to intelligent Rosemount transmitters.