Table 7-20 Definitions Of Analog Input Function Block System Parameters - Emerson Rosemount OCX8800 Instruction Manual

Instruction Manual
IM-106-880C, OI
The Analog Input (AI) function block processes field device measurements and makes them
available to other function blocks. The output value from the AI block is in engineering units and
contains 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 number
to define the variable that the AI block processes.
The AI block supports alarming, signal scaling, signal filtering, signal status calculation, mode
control, and simulation. In Automatic mode, the block's output parameter (OUT) reflects the
process variable (PV) value and status. In Manual mode, OUT may be set manually. The Manual
mode is reflected on the output status. A discrete output (OUT_D) is provided to indicate
whether a selected alarm condition is active. Alarm detection is based on the OUT value and
user specified alarm limits.
measure, descriptions, and index numbers.

Table 7-20 Definitions of Analog Input Function Block System Parameters

Index
Parameter Number Units
ACK_OPTION 23
ALARM_HYS 24
ALARM_SEL 38
ALARM_SUM 22
ALERT_KEY 04
BLOCK_ALM 21
BLOCK_ERR 06
CHANNEL 15
FIELD_VAL 19
GRANT_DENY 12
HI_ALM 34
HI_HI_ALM 33
Introduction
Table 7-20
Description
None Used to set auto acknowledgment of alarms.
Percent The amount the alarm value must return within the alarm limit before
the associated active alarm condition clears.
None Used to select the process alarm conditions that will cause the OUT_D
parameter to be set.
None The summary alarm is used for all process alarms in the block. The
cause of the alert is entered in the subcode field. The first alert to be-
come 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 alert may be reported without clearing the Active status, if the
subcode has changed.
None The identification number of the plant unit. This information may be
used in the host for sorting alarms, etc.
None The block alarm is used for all configuration, hardware, connection
failure 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 alert may be
reported without clearing the Active status, if the subcode has
changed.
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.
None The CHANNEL value is used to select the measurement value. Refer to
the appropriate device manual for information about the specific chan-
nels available in each device.
You must configure the CHANNEL parameter before you can configure
the XD_SCALE parameter.
Percent The value and status from the transducer block or from the simulated
input when simulation is enabled.
None Options for controlling access of host computers and local control pan-
els to operating, tuning, and alarm parameters of the block. Not used
by device.
None The HI alarm data, which includes a value of the alarm, a timestamp of
occurrence and the state of the alarm.
None The HI HI alarm data, which includes a value of the alarm, a timestamp
of occurrence and the state of the alarm.
lists the AI block parameters and their units of
Section 7: Foundation
Fieldbus
April 2017
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