Process Process measurement measurements s .1

SCD Application guidelinesSCD Application guidelines

E.3 Application Application typical typical

E.3.1 Process Process measurement measurements s .1

E.3 Application Application typical typical

This chapter will give a selection of a various application typical. Only a few selected inputs and outputs for This chapter will give a selection of a various application typical. Only a few selected inputs and outputs for the function templates will be used in

the function templates will be used in the examples.the examples.

E.3.1 E.3.1 Process Process measurement measurements s

E.3.1.1

E.3.1.1 Analogue Analogue measurememeasurementsnts

For monitoring and display of analogue process variables, the

For monitoring and display of analogue process variables, the MA-template shall be used. The templateMA-template shall be used. The template comprises functions for action and warning

comprises functions for action and warning alarm as well as alarm as well as loop fault annunciation. Additionloop fault annunciation. Additionally theally the template handles limit-checking for status outputs (events) without any

template handles limit-checking for status outputs (events) without any alarm annunciation.alarm annunciation.

Applicable alarm handling attributes (AHH, WH, WL, A

Applicable alarm handling attributes (AHH, WH, WL, A LL) and status/event handling attributes (BXHH, BXH,LL) and status/event handling attributes (BXHH, BXH, BXL, BXLL) shall be identified on the

BXL, BXLL) shall be identified on the SCD:SCD:

All alarm, warning and event limits

All alarm, warning and event limits need to be specified within the SAS need to be specified within the SAS system.system.

Warning alarms with no signal outputs (no actions), shall only be presented on the VDU and in the Warning alarms with no signal outputs (no actions), shall only be presented on the VDU and in the alarm/event lists.

alarm/event lists.

C19 C19

TT TT 0407 0407 39 MA 39

AHH AHH

BXL BXL BXH

P21 BXH

P21

PST PST 0302 0302 21 MA 21

AHH AHH

ALL ALL WL WL WH WH

E.3.1.2 Totalization E.3.1.2 Totalization Totalization of flow is

Totalization of flow is handled by a separate function template, the QA template. The template calculates thehandled by a separate function template, the QA template. The template calculates the accumulated

accumulated flow over a final flow over a final interval in time by interval in time by integrating the measured instantaneintegrating the measured instantaneous flow. Theous flow. The accumulated

accumulated flow calculation can be started, stopped or reset either from the OS or by flow calculation can be started, stopped or reset either from the OS or by logic input.logic input.

The calculated

The calculated accumulated accumulated flow is monitored and compared to HH action and H warning alarms and a HHflow is monitored and compared to HH action and H warning alarms and a HH status (event) output without alarm annunciation. Applicable alarms and events shall be

status (event) output without alarm annunciation. Applicable alarms and events shall be shown on theshown on the SCD’s.

SCD’s.

The analogue value can be connected directly to the

The analogue value can be connected directly to the x input on the x input on the QA template, a MAQA template, a MA template should template should onlyonly be used either in

be used either in series or parallel when indicationseries or parallel when indication of the present measured flow of the present measured flow on the operator station ison the operator station is necessary.

E.3.1.3 Compensation Compensation of of measured measured flowflow For accurate volumetric flow calculations, the

For accurate volumetric flow calculations, the measured flow must be compensated for pressure andmeasured flow must be compensated for pressure and temperature. For calculation of standardized flow, the measurement additionally have to be density temperature. For calculation of standardized flow, the measurement additionally have to be density compensated

compensated. Type of . Type of function template is not specified by function template is not specified by the NORSOK standard, a vendor specificthe NORSOK standard, a vendor specific template may be used.

template may be used.

E.3.1.4

E.3.1.4 Differential Differential pressure pressure measuremenmeasurementt

For measuring of differential pressure in the process, it

For measuring of differential pressure in the process, it may may be indicated on the SCD from where and tobe indicated on the SCD from where and to where the measurement is performed, with simple lines, i.e. across a filter in the process

where the measurement is performed, with simple lines, i.e. across a filter in the process line, as shown inline, as shown in the figure:

the figure:

MA MA C01 C01

44 44 PDT PDT 0012 0012

E.3.1.5

E.3.1.5 Binary Binary measurememeasurementsnts

The MB-template shall be utilised for monitoring and display of

The MB-template shall be utilised for monitoring and display of binary process variables or digital inputs. binary process variables or digital inputs. TheThe MB-template comprises functions for

MB-template comprises functions for operator alarming and action initiation:operator alarming and action initiation:

LSL LSL 0139 0139 53 MB 53

MB C19

C19 ACTIONACTION

OUTPUT OUTPUT

Digital inputs not initiating any actions or

Digital inputs not initiating any actions or alarms shall only be alarms shall only be used as input to used as input to function templates operatingfunction templates operating the actual controlled object. E.g. for XSV’s, a ZSL limit switch shall give input to

the actual controlled object. E.g. for XSV’s, a ZSL limit switch shall give input to the position low input (XGL)the position low input (XGL) of the SBV. A mismatch between the position low input and the normal function output (Y) of the SBV will of the SBV. A mismatch between the position low input and the normal function output (Y) of the SBV will then generate a fau

then generate a fault alarm and lt alarm and switch the valve to manual moswitch the valve to manual mode if in auto. The valve position wide if in auto. The valve position will bell be maintained. The feedback signal from the limit switch

maintained. The feedback signal from the limit switch should should not be shown on the SCD:not be shown on the SCD:

XSV XSV 0163 0163 23 SBV 23

SBV

ZSL ZSL

P21 P21

E.3.1.6

E.3.1.6 Action Action and and warning warning alarmsalarms

Action alarms are alarms initiating automatic interlocking actions in

Action alarms are alarms initiating automatic interlocking actions in addition to alarm annunciation in CCR.addition to alarm annunciation in CCR.

The interlock shall be performed independently of the mode (auto/manual) of the

The interlock shall be performed independently of the mode (auto/manual) of the interlocked object:interlocked object:

PT PT 0031 0031

62 MA 62

MA C20 C20

O O

HV HV 0030 0030 62 SBV 62

SBV

AHH AHH

ALL ALL

L L S S L L

C20 C20

WH WH

WL WL

Warning alarms are alarms warning the

Warning alarms are alarms warning the operator about an undesired process upset. A operator about an undesired process upset. A warning alarmwarning alarm enables the operator to perform corrective actions,

enables the operator to perform corrective actions, but no automatic action is initiated. The but no automatic action is initiated. The alarmalarm annunciation in CCR requires

annunciation in CCR requires acknowledgeacknowledgement by the ment by the operator:operator:

C20 C20

TT TT 0762 0762 41 MA 41

MA

^WL^WL

WH WH

E.3.1.7

E.3.1.7 Action Action blockingblocking

Action alarms may be blocked from

Action alarms may be blocked from initiating the actual interlocking action, but still initiating the actual interlocking action, but still give alarm annunciation.give alarm annunciation.

Blocking from the OS blocks

Blocking from the OS blocks all action outputs while single action all action outputs while single action outputs may be blocked by external logic:outputs may be blocked by external logic:

P21 P21

PST PST 0057 0057 43 MA 43

MA

AHH AHH F

F B B H H H H

E.3.1.8

E.3.1.8 Alarm Alarm suppresssuppressionion Action alarms as well

Action alarms as well as alarm annunciation may be suppressed. Suppression from the OS as alarm annunciation may be suppressed. Suppression from the OS suppresses allsuppresses all interlocking action outputs, alarm and fault annunciation. Single alarms may be suppressed by external logic:

interlocking action outputs, alarm and fault annunciation. Single alarms may be suppressed by external logic:

MAIN MAIN EN820001 EN820001 PA530001A PA530001A 0001A

0001A 53 SBE 53 SBE C25 C25

PA PA

0352 0352 53 MA 53 MA

PT PT

ALL ALL

T T

F F U U L L L L L

L S S L L

BCL BCL

2S YH 2S

YL YL

C25 C25

In document I-005 System Control Diagram (Page 64-68)