Rosemount 848T

Reference Manual

00809-0100-4697, Rev EA October 2011

Figure D-2. Analog Input

Function Block Schematic

Analog

Measurement

Access

 

ALM_SEL

 

HI_HI_LIM

 

 

Analog

Alarm

 

Meas.

HI_LIM

OUT_D

 

LO_LO_LIM

Detection

 

 

CHANNEL

LO_LIM

 

 

ALARM_HYS

 

 

 

 

 

LOW_CUT

OUT

Convert

Cutoff

Filter

PV

Status

 

 

 

Calc.

SIMULATE

L_TYPE

PV_FTIME

 

 

 

MODE

 

 

 

 

 

FIELD_VAL

IO_OPTS

STATUS_OPTS

 

 

 

OUT_SCALE

XD_SCALE

F

OUT = Block output value and status

OUT_D = Discrete output that signals a selected alarm condition

Filtering

The filtering feature changes the response time of the device to smooth variations in output readings caused by rapid changes in input. Adjust the filter time constant (in seconds) using the PV_FTIME parameter. Set the filter time constant to zero to disable the filter feature.

Signal Conversion

Set the signal conversion type with the Linearization Type (L_TYPE) parameter. View the converted signal (in percent of XD_SCALE) through the FIELD_VAL parameter.

FIELD_VAL =

100-------------------------------------------------------------------------------------------× (Channel Value EU*@0%)

 

 

(EU*@100% EU*@0%)

* XD_SCALE values

 

 

Choose from direct, indirect, or indirect square root signal conversion with the

L_TYPE parameter.

Direct

Direct signal conversion allows the signal to pass through the accessed channel input value (or the simulated value when simulation is enabled).

PV = Channel Value

Indirect

Indirect signal conversion converts the signal linearly to the accessed channel input value (or the simulated value when simulation is enabled) from its specified range (XD_SCALE) to the range and units of the PV and OUT parameters (OUT_SCALE).

PV =

FIELD_VAL

× (EU**@100% EU**@0%) + EU**@0%

------------------------------100

 

 

** OUT_SCALE values

D-4

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Image 94
Emerson 848T manual Filtering, Signal Conversion, Direct, Indirect

848T specifications

The Emerson 848T is a state-of-the-art temperature transmitter designed for accurate and reliable temperature measurement in various industrial applications. This device has gained recognition for its advanced features and robust performance, making it a popular choice among engineers and technicians in the field.

One of the key highlights of the Emerson 848T is its unique dual-channel capability, which allows it to seamlessly monitor two temperature sources simultaneously. This functionality is particularly beneficial in processes where multiple temperature points need to be assessed, optimizing efficiency and reducing the need for additional equipment. It supports various sensor types, including thermocouples, RTDs, and resistance temperature detectors, making it versatile for different applications.

The 848T is equipped with sophisticated digital processing technology, which enhances its accuracy and stability. It features a 24-bit analog-to-digital converter, ensuring precise measurement and minimizing drift over time. Moreover, the device boasts a wide operating temperature range, accommodating ambient conditions from -40°C to 85°C. This durability makes it suitable for harsh environments commonly encountered in industries such as oil and gas, pharmaceuticals, and power generation.

Another significant characteristic of the Emerson 848T is its configurable output options. Users can choose from a range of output signals, including 4-20 mA, which provides a standard interface for integration into existing control systems. Additionally, it offers a HART communication protocol, allowing for easy configuration, calibration, and diagnostics through a digital interface. This feature enhances the transmitter's usability, enabling operators to perform adjustments without direct access to the device.

The device is designed with user-friendliness in mind. Its intuitive setup procedure and robust graphical user interface simplify the commissioning process, ensuring that even those new to the technology can easily navigate the system. An integrated LCD display provides real-time readings and status information, facilitating monitoring at a glance.

In summary, the Emerson 848T temperature transmitter combines reliable performance, user-friendly design, and advanced digital technologies. Its dual-channel capability, wide sensor compatibility, and adjustable output options make it an essential tool for achieving precise temperature measurements in various industrial settings. With these compelling features, the Emerson 848T stands out as a leading choice for professionals seeking accuracy and efficiency in their temperature monitoring applications.