A1.1 scope and purpose, A1.2 using the axr for an sisapplication, A1.2.1 safety accuracy – Yokogawa ADMAG AXR User Manual

Page 186: A1.2.2 diagnostic response time, A1.2.3 setup, A1.2.4 required parameter settings, A1.2.5 proof testing, A1.1, A1.2, A1.2.2

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<Appendix1. Safety Instrumented Systems Installation>

A1-1

IM 01E30D01-01EN

Appendix 1. Safety Instrumented Systems

Installation

WARNING

The contents of this appendix are cited from

exida.com safety manual on the AXR series

flowmeter specifically observed for the safety

flowmeter purpose. When using the AXR for

Safety Instrumented Systems (SIS) application,

the instructions and procedures in this section

must be strictly followed in order to preserve the

flowmeter for that safety level.

A1.1 Scope and Purpose

This section provides an overview of the user

responsibilities for installation and operation of the

AXR in order to maintain the designed safety level

for Safety Instrumented Systems (SIS) applications.

Items that will be addressed are proof testing, repair

and replacement of the transmitter, reliability data,

lifetime, environmental and application limits, and

parameter settings.

A1.2 Using the AXR for an SIS

Application

A1.2.1 Safety Accuracy

The AXR has a specified safety accuracy of 2%.

This means that the internal component failures are

listed in the device failure rate if they will cause an

error of 2% or greater.

A1.2.2 Diagnostic Response Time

The AXR will report an internal failure within 8

seconds of the fault occurrence.

A1.2.3 Setup

During installation the flowmeter must be setup

with engineering units parameters. This is typically

done with a handheld terminal. These parameters

must be verified during the installation to insure

that the correct parameters are in the flowmeter.

Engineering range parameters can be verified by

reading these parameters from the optional local

display or by checking actual calibration of the

flowmeter.

The calibration of the flowmeter must be performed

after parameters are set.

A1.2.4 Required Parameter Settings

The following parameters need to be set in order to

maintain the designed safety integrity.

Table A1.1 Required Parameter Settings

Item

Description

Burnout direction

switch

To specify if the output should go

21.6 mA or higher or 3.2 mA or lower

upon detection of an internal failure.

Write protection

switch

The write function should be

disabled.

A1.2.5 Proof Testing

The objective of proof testing is to detect failures

within the flowmeter that are not detected by the

diagnostics of the flowmeter. Of main concern

are undetected failures that prevent the safety

instrumented function from performing its intended

function. See table A1.2 for proof testing method.
The frequency of the proof tests (or the proof

test interval) is to be determined in the reliability

calculations for the safety instrumented functions

for which the AXR is applied. The actual proof tests

must be performed more frequently or as frequently

as specified in the calculation in order to maintain

required safety integrity of the safety instrumented

function.
The following tests need to be specifically executed

when a proof test is performed. The results of

the proof test need to be documented and this

documentation should be part of a plant safety

management system. Failures that are detected

should be reported to Yokogawa.
The personnel performing the proof test of the

flowmeter should be trained in SIS operations

including bypass procedures, AXR flowmeter

maintenance, and company management of

change procedures.

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