Rosemount 848T

Reference Manual

00809-0100-4697, Rev EA October 2011

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 =

Channel Value

× (EU**@100% EU**@0%) + EU**@0%

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

** OUT_SCALE values

Indirect Square Root

Indirect Square Root signal conversion takes the square root of the value computed with the indirect signal conversion and scales it to the range and units of the PV and OUT parameters.

 

 

Channel Value

 

PV =

--------------------------------------

100

× (EU**@100% EU**@0%) + EU**@0%

 

 

 

 

** OUT_SCALE values

 

When the converted input value is below the limit specified by the LOW_CUT

 

parameter, and the Low Cutoff I/O option (IO_OPTS) is enabled (True), a

 

value of zero is used for the converted value (PV). This option is useful to

 

eliminate false readings when the differential temperature measurement is

 

close to zero, and it may also be useful with zero-based measurement

 

devices such as flowmeters.

 

 

 

 

 

 

NOTE

 

 

 

 

Low Cutoff is the only I/O option supported by the MAI block. Set the I/O

 

option in Manual or Out of Service mode only.

 

 

 

 

 

 

Block Errors

 

 

 

Table D-5lists conditions reported in the BLOCK_ERR parameter. Conditions

 

in bold are inactive for the MAI block and are given for reference.

Table D-5. BLOCK_ERR

 

 

 

 

Conditions

Number

Name and Description

 

0

Other

 

 

 

1

Block Configuration Error: the selected channel carries a measurement that is

 

 

incompatible with the engineering units selected in XD_SCALE, the L_TYPE

 

 

parameter is not configured, or WRITE_CHECK = zero.

 

2

Link Configuration Error

 

3

Simulate Active: Simulation is enabled and the block is using a simulated value in

 

 

its execution.

 

 

4

Local Override

 

 

5

Device Fault State Set

 

6

Device Needs Maintenance Soon

 

7

Input Failure/Process Variable has Bad Status: The hardware is bad, or a bad

 

 

status is being simulated.

 

8

Output Failure: The output is bad based primarily upon a bad input.

 

9

Memory Failure

 

 

10

Lost Static Data

 

 

11

Lost NV Data

 

 

12

Readback Check Failed

 

13

Device Needs Maintenance Now

 

14

Power Up

 

 

15

Out of Service: The actual mode is out of service.

D-12

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Emerson 848T Devices such as flowmeters, Option in Manual or Out of Service mode only, Table D-5. Blockerr Conditions

848T specifications

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