Yokogawa RAGN - Manual (Page 42)

<A1. SAFETY INSTRUMENTED SYSTEMS INSTALLATION>
A1-2
IM 01R01B10-00E-E 2nd edition: November 01, 2011-00 All Rights Reserved. Copyright © 2011, Rota Yokogawa
A1.2.2 Diagnostic Response Time
There is neither diagnostic in the magnetic reed contacts [V1] nor in the inductive ring sensors [V2], [V3].
A1.2.3 Setup
A setup of the flow meter is not required. Installation shall be done according to the manual.
Precautions for use of ring sensors [V2], [V3] in Safety Instrumented Functions:
The high output current should be used as the preferred “safe state”. Therefore to achieve highest reliability of
the system, the orientation of the ring sensors should be set according to the application to set high current
as safe state. For more information on assembly see User’s Manual, Model RAGN Glass Rotameter,
IM 01R01B10-00E-E.
A1.2.4 Proof Testing
The objective of proof testing is to detect failures within the flow meter. Of main concern are undetected
failures that prevent the safety instrumented function from performing its intended function.
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 flow meter 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.
Proof test for RAGN Glass Rotameter with magnetic contacts and inductive ring sensors:
Step Action
1 Take appropriate action to avoid a false trip
2 Inspect the device for any visible damage, corrosion or contamination.
3a Force the RAGN Glass Rotameter to reach a defined “MAX” threshold value and verify that the
magnetic contact or inductive ring initiator goes into the safe state.
Note: only applicable if RAGN is equipped with a “MAX” contact.
3b Force the RAGN Glass Rotameter to reach a defined “MIN” threshold value and verify that the
magnetic contact or inductive ring initiator goes into the safe state.
Note: only applicable if RAGN is equipped with a “MIN” contact.
4 Restore the loop to full operation
5 Restore normal operation
When all the tests listed above are executed a proof test coverage of approximately 99% of possible DU
failures in the RAGN Glass Rotameter can be claimed.
The following tools need to be available to perform proof testing:
Measurement instrument to verify output status of the magnetic reed contacts [V1] or inductive ring sensors
[V2], [V3]
The person(s) performing the proof test of the Yokogawa RAGN Glass Rotameter should be trained in SIS
operations including bypass procedures, flow meter maintenance and company management of change
procedures.
A1.2.5 Repair and replacement
Maintenance information can be found in section Service of the User’s Manual, Model RAGN Glass
Rotameter, IM 01R01B10-00E-E.
If repair is to be performed with the process online the Rota Yokogawa RAGN Glass Rotameter will need to
be bypassed during the repair. The user should setup appropriate bypass procedures for that.
Contact the Yokogawa sales office if this instrument requires repair
The person(s) performing the repair and / or replacement of the Rota Yokogawa RAGN Glass Rotameter
should have a sufficient skill level.