Reference Manual

00809-0100-4697, Rev EA October 2011

Rosemount 848T

MULTIPLE ANALOG INPUT (MAI) FUNCTION BLOCK

 

 

 

 

OUT_1

 

 

 

 

 

 

 

 

OUT_2

 

 

 

 

 

MAI

 

 

OUT_3

 

 

 

 

 

 

OUT_4

 

 

 

 

 

 

 

OUT_5

 

 

 

 

 

 

 

 

OUT_6

 

 

 

 

 

 

 

 

OUT_7

 

 

 

 

 

 

 

 

OUT_8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Multiple Analog Input (MAI) function block has the ability to process up to eight field device measurements and make them available to other function blocks. The output values from the MAI block are in engineering units and contain a status indicating the quality of the measurement. The measuring device may have several measurements or derived values available in different channels. Use the channel numbers to define the variables that the MAI block processes.

The MAI block supports signal scaling, signal filtering, signal status calculation, mode control, and simulation. In Automatic mode, the block’s output parameters (OUT_1 to OUT_8) reflects the process variable (PV) values and status. In Manual mode, OUT may be set manually. The Manual mode is reflected on the output status. Table D-4lists the MAI block parameters and their units of measure, descriptions, and index numbers. The block execution time is 30 ms.

Out1 = The block output value and status for the first channel.

Table D-4. Multiple Analog Input Function Block Parameters

Number

Parameter

Units

Description

1

ST_REV

None

The revision level of the static data associated with the input selector block. The

 

 

 

revision value will be incremented each time a static parameter value in the block is

 

 

 

changed.

2

TAG_DESC

None

The user description of the intended application of the block.

3

STRATEGY

None

The strategy field can be used to identify grouping of blocks. This data is not

 

 

 

checked or processed by the block.

4

ALERT_KEY

None

The identification number of the plant unit. This information may be used in the host

 

 

 

for sorting alarms, etc.

5

MODE_BLK

None

The actual, target, permitted, and normal modes of the block.

 

 

 

Actual: The mode the “block is currently in”

 

 

 

Target: The mode to “go to”

 

 

 

Permitted: Allowed modes that target may take on

 

 

 

Normal: Most common mode for target

6

BLOCK_ERR

None

This parameter reflects the error status associated with the hardware or software

 

 

 

components associated with a block. It is a bit string, so that multiple errors may be

 

 

 

shown.

7

CHANNEL

None

Allows for custom channel setting. Valid values include:

 

 

 

0: Unitialized

 

 

 

1: Channels 1 to 8 (index values 27 to 34 can only be set to their corresponding

 

 

 

channel number, i.e. CHANNEL_X=X)

 

 

 

2: Custom settings (index values 27 to 34 can be configured for any valid channel

 

 

 

as defined by the DD)

8, 9, 10, 11,

OUT (1, 2, 3, 4, 5,

EU of OUT_SCALE

The block output value and status

12, 13, 14,

6, 7, 8)

 

 

15

 

 

 

16

UPDATE_EVT

None

This alert is generated by any change to the static data

17

BLOCK_ALM

None

The block alarm is used for all configuration, hardware connection feature, or

 

 

 

system problems in the block. The cause of the alert is entered in the subcode field.

 

 

 

The first alert to become active will set the Active status in the Status parameter. As

 

 

 

soon as the Unreported status is cleared by the alert reporting task, another block

 

 

 

may be reported without clearing the Active status, if the subcode has changed.

18

SIMULATE

None

A group of data that contains the current sensor transducer value and status, and

 

 

 

the enable/disable bit.

D-9

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Emerson 848T manual Multiple Analog Input MAI Function Block, Table D-4. Multiple Analog Input Function Block Parameters

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.