Differences Between Smart Pressure Transmitter and Analog Pressure Transmitter

Pressure transmitter is composed of single chip microcomputer and micro displacement (differential) pressure sensitive element, which can complete multi-function detection and conversion from non electric quantity to electric quantity.

Rosemount smart Transmitter 3051TG4A2B21JS5B4E5Q4Q8M5T1CNP1

Figure 1: Rosemount Smart Transmitter

With the development of microprocessor technology and digital communication technology, smart pressure transmitter is produced. It is a new type of pressure transmitter with digital processing and digital communication ability.

The so-called smart pressure transmitter uses microprocessor in the pressure transmitter. Through software, the use of microprocessor can realize some functions that analog pressure transmitter cannot achieve.

Compared with traditional analog pressure transmitter, smart pressure transmitter has the following advantages.

Communication Ability

When the smart pressure transmitter is connected with DCS adopting the same communication protocol, it can carry out direct two-way digital communication. The smart pressure transmitter can be adjusted by remote control in the control room through the manual terminal, while the analog pressure transmitter can only be adjusted in the field. The calibration of zero point and range of smart pressure transmitter is independent, which can be completed only once.

Self - Diagnosis Ability

When using the pressure transmitter, you can find the correct and clear fault information on the manual terminal or the screen of DCS, which makes it convenient for the maintenance personnel to quickly remove the fault, improving the reliability and availability of the system of transmitter.

Function of PID (Proportional Integral Derivative) Controller

The function of PID controller is added to the transmitter by software, so that the pressure transmitter has the function. This pressure transmitter can be directly connected with the actuator, so smart pressure transmitter is promising.

Rosemount In-line smart pressure transmitter 3051 Series measurement type:Gage Pressure output:4-20mA

Figure 2: Rosemount Smart Transmitter 3051TG1A2C21AB4M5I5

Measurement Range

The smart pressure transmitter has a larger measurement range.

*Measurement range = Maximum range / Working range
*Maximum measurement range = Maximum range / Minimum working range

Therefore, large measurement range reduces specifications of the transmitter.

Strong Stability

Generally, smart pressure transmitter has reliable temperature compensation and static pressure compensation. The detection principle of smart pressure transmitter mainly includes capacitive type, diffusion silicon type and inductive type, and the first two types are the main types. The output signals of smart pressure transmitter are analog (4 - 20mA) and digital. In addition to linear and square root output signals, some transmitter products can also output PID operation signal, which are also called smart transmission controller.　

Smart pressure transmitters have been used in China since 1990s. At present, there are more than ten series of pressure transmitters from nearly ten manufacturers in the market.