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Process alarm display block (pad), 6 process alarm display block (pad) – Micromod MOD: 30ML Functions Data Base Reference User Manual

Page 57

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MOD 30ML Functions

PROCESS ALARM DISPLAY BLOCK


2.6

PROCESS ALARM DISPLAY BLOCK (PAD)

The process alarm block is used to initiate a discrete alarm signal to advise the operator of
an irregular process condition. The alarm is calculated by comparing an alarm source with a
trip value. The alarm source (input) is usually a value in some other block that the operator
wishes to monitor. The type of comparison made is specified by the trip condition. Depending
on the result of the comparison, the alarm is considered active or clear (inactive).

The alarm source value is shown on line 6 of the front panel display. The source value can
also be indicated on a bar display that includes an intensified segment identifying the trip
point.

This block has two discrete outputs that indicate whether the alarm is active or
acknowledged. These outputs can be used to initiate logic in other blocks throughout the
database. The user can acknowledge the existence of an alarm by any one of several
methods as described in Section 2.6.1. A functional block diagram of the block is shown in
Figure 2-19.

Alarm Input LSP Quality

Acknowledge Input LSP Quality

YES

Process Alarm Calculation

(See example diagram)

Trip Condition

Hysteresis

(Floating Point

Alarm)

* Data Type may be?

Count, Discrete, Short State,

Long State, Floating Point,

Msec Time, or Date

NO

Report Events

Trip Value *

Priority

(0 to 255)

Less

Less or Equal

Greater

Greater or Equal

Equal

Not Equal

Deviation

Suppress

Calculation

(YES, NO)

Quality Check

AQ

UQ

U

A

Scaling

HRNG

LRNG

TAG1

TAG2

GOOD

BAD

NONE

Discrete

LSP

LSP *

Value

Alarm Input

GOOD

BAD

Bad Inputs

Accepted

(YES, NO)

State

(RUN, HOLD,

OFF, DEBUG))

Acknowledge

Input

Figure 2-19. Functional Block Diagram, Process Alarm Display Block

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