Transmitters

Process transmitters are field-mounted instruments that measure a physical variable — pressure, differential pressure, temperature, flow, or level — and output a standardized electrical signal (typically 4–20 mA or digital protocols such as HART, Foundation Fieldbus, or PROFIBUS) for transmission to control systems, PLCs, and data acquisition devices. By conditioning and transmitting sensor data over long distances with high noise immunity, transmitters are fundamental to closed-loop process control in industrial plants.

Transmitters are available for virtually every measurable process variable and are specified by accuracy, measurement range, process connection type, and communication protocol. In safety-critical environments such as oil & gas and chemical processing, transmitters must meet SIL (Safety Integrity Level) ratings and hazardous area certifications such as ATEX or IECEx.

Typical Applications

Pressure and differential pressure measurement in oil & gas pipelines and refineries
Temperature transmission via RTD or thermocouple inputs in chemical processing plants
Humidity and dewpoint monitoring in cleanrooms and pharmaceutical manufacturing
Level measurement in storage tanks and water treatment facilities
Flow measurement in utilities, HVAC, and process industries

Popular Brands

Rosemount (Emerson) is the global market leader in pressure and differential pressure transmitters, offering the widely deployed 3051 series with HART, WirelessHART, and Foundation Fieldbus options. Testo produces compact transmitters for humidity, dewpoint, and pressure measurement suited to HVAC and refrigeration applications. Other major manufacturers include Yokogawa, ABB, Endress+Hauser, and Honeywell.