ABSTRACT
Motion-Balance Transmitters 552 Transmitters Grouped by Measured Variable 552
Differential Pressure Transmitter 552 Square Root-Extracting d/p Transmitter 553
Variable Area Flow Transmitter 553 Filled Bulb Temperature Transmitter 554 Buoyancy Transmitter (Level or Density) 554 Force Transmitter 555 Motion Transmitter 556 Speed Transmitter 557
Transmission Lag 557 Bibliography 558
3.9 TRANSMITTERS: SELF-CHECKING AND SELF-VALIDATING 559
Introduction 559 Levels of Diagnostic Information 559
How Diagnostics Are Performed 559 Diagnostics Transmission 561
Analog Transmitters 561 Microprocessor-Based Transmitters 561
Diagnostic Information Displays 563 Portable and Handheld Displays 563
Acting on the Diagnostic Data 565
Failsafe and Alarm Actions 565 Reference 566
3.10 TRANSMITTERS: SMART, MULTIVARIABLE, AND FIELDBUS 567
Introduction 567 Operation and Performance 567
Digital Sensors 568 Sensor Compensation and Characterization 568 Multivariable and Inferential Sensors 569 HART Communication 570 Fieldbus Transmitters 570
Benefits of Advanced Transmitters 570 Savings 570 Installation and Commissioning 571 Parameterization 571 Integration into DCS and PLC Systems 572 Building Control Loops 573
Reference 574
HISTORY AND DEVELOPMENT
Pneumatic controllers were first introduced at the turn of the twentieth century. They logically followed the development of diaphragm-actuated valves in the 1890s. Early types were all direct connected, local mounting, indicating, or blind types. Large-case indicating and circular chart recording controllers appeared around 1915. All early models incorporated twoposition, on/off action or proportional action. It was not until 1929 that reset action was introduced. Rate action followed in 1935.
