Emerson Fisher FIELDVUE DVC6000f, Инструкция по эксплуатации, Страница: 201 / 384

MAI Function Block
December 2009 4-141
Figure 4-27. Multiple Analog Input (MAI) Function Block
FIELDBUS-FBUS_31A
OUT_1
Out1 = The block output value and status
for the first channel
MAI
OUT_2
OUT_3
OUT_4
OUT_5
OUT_6
OUT_7
OUT_8
Multiple Analog Input (MAI) Function
Block Overview
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 mode control. In Automatic
mode, the block’s output parameters (OUT_1 to
OUT_8 [8 through 15]) reflects the process variable
(PV) values and status. In Manual mode, OUT may be
set manually. The Manual mode is reflected in the
output status. Table 4-63 lists the MAI block
parameters, and their units of measure, description
and index numbers.
Modes
The MAI Function Block supports three modes of
operation as defined by the MODE_BLK [5]
parameter:
Manual (Man)—The block output (OUT_1 to
OUT_8 [8 through 15]) may be set manually.
Automatic (Auto)—OUT_1 to OUT_8 [8 through
15] reflects the analog input measurement or the
simulated value when the simulation is enabled.
Out of Service (OOS)—The block is not
processed. PV is not updated and the OUT status is
set to Bad: Out of Service. The BLOCK_ERR [6]
parameter shows Out of Service. In this mode, you
can make changes to all configurable parameters. The
target mode of a block may be restricted to one or
more of the supported modes.
Status Handling
In Man mode, the OUT status constant limit is set to
indicate that the value is a constant and the OUT
status is Good.
OUT_X status will be Bad if the transducer detects a
problem with sensor associated with the channel.
Application Information
The intended use is for applications where it is
necessary to convey DVC6000f measurements from a
function.
The configuration of the MAI function block and its
associated output channels depends on the specific
application.
CHANNEL [7]: Channel must always be set to
21.
The output parameters (OUT_1 to OUT_8 [8 through
15]) are set through the transducer block Instrument
menu. Each output has a channel assigned to it in MAI
Channel Map (TB.MAI_CHANNEL_MAP [95]) in the
transducer block. For additional information, refer to
table 4-63.
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