Emerson Process Management Essential Mobrey Level Switch Manual for Functional Safety and Maintenance

Functional Safety Manual

IP101/FSM, Rev AA

January 2012

Horizontal Float Switch

INTRODUCTION

Scope and Purpose of the Safety Manual

This safety manual contains the information to design, install, verify and maintain a Safety Instrumented Function (SIF) utilizing the Mobrey magnetic level switch.

The manual provides the necessary requirements to enable the integration of the horizontal point-level float switch when showing compliance with the IEC 61508 or IEC 61511 functional safety standards. It indicates all assumptions that have been made on the usage of the level switch. If these assumptions cannot be met by the application, the Safety Integrity Level (SIL) capability of the product may be adversely affected.

Skill Level Requirement

Terms, Abbreviations, And Acronyms

NOTE:

For product support, use the contact details on the back page.

System design, installation and commissioning, and repair and maintenance shall be carried out by suitably qualified personnel.

Basic Safety

Freedom from unacceptable risk of harm.

BPCS

Basic Process Control System – a system which responds to input signals from the process, its associated equipment, other programmable systems and/or an operator and generates output signals causing the process and its associated equipment to operate in the desired manner but which does not perform any safety instrumented functions with a claimed SIL greater than or equal to 1.

Fail-safe State

State where switch output is in the state corresponding to an alarm condition. In this condition the switch contacts will normally be open.

Fail Dangerous

Failure that does not respond to an input from the process (i.e. not switching to the fail-safe state).

Fail Dangerous Detected

Failure that is dangerous but is detected.

Fail Dangerous Undetected

Failure that is dangerous and that is not detected.

Fail No Effect

Failure of a component that is part of the safety function but that has no effect on the safety function.

Fail Safe

Failure that causes the switch to go to the defined fail-safe state without an input from the process.