Temperature transmitter: Fieldbus networking simplifies wiring

By Control Engineering Staff December 20, 2007


The TFZ programmable Foundation Fieldbus temperature transmitter from Moore Industries takes the analog signal from a temperature sensor and digitizes it to send the variable to the larger DCS via the H1 segment. The company says the transmitter can interface with 14 RTD types, and nine thermocouple types, as well as direct millivolt and resistance/potentiometer inputs.

The TFZ transmitter can be installed on the same segment with all standard Foundation Fieldbus devices. The bus-powered, two-wire TFZ consumes only 10.5 mA in normal operation and offers dozens of input and operation choices. It can be set up from the control room over segment wiring, using a standard Foundation Fieldbus configuration tools.

The TFZ is Factory Mutual approved for use in Class I, Division 1, Groups A, B, C, D and Class II & III, Division 1, Groups E, F, G hazardous areas. It also has NEMA 4X and IP66 ratings, approvals from ATEX, cFMus (US/Canada), IECEx, CSA, cCSAus, CENELEC/ATEX 94/9/EC and ANZEx, and is CE conformant. The TFZ operates in ambient temperature ranges of

Moore says TFZ transmitters perform continuous sensor diagnostics. This patented feature can save lost production time and simplifies troubleshooting. If the sensor breaks or otherwise stops sending a signal during operation, the transmitter instantly displays the type and location of the error on its display.

The TFZ has 20-bit input resolution, RFI/EMI protection, ambient temperature compensation, works up to five years between scheduled calibrations, and—depending on the sensor chosen—has an input accuracy up to

Resource function block (RB)—Contains diagnostic information, hardware and electronics information (memory, manufacturer identification, device type, software tag) and display configuration parameters.

Temperature transducer block (TB)—Contains temperature measurement data, including sensor and terminal temperature. It also includes information about the sensor type, engineering units, linearization, re-ranging, damping, temperature compensation and diagnostics.

Analog input block (AI)—Processes measurements from a sensor and makes them available to other function blocks. The output value from the AI block is displayed in engineering units and contains a status indicating the quality of the measurement.

—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com ,
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