Terminology - Allen-Bradley PowerFlex 755 User Manual

Preface

Table 1 - Abbreviations and Definitions

Abbreviation

Full Term

1oo2

One out of Two

CAT

Category

CL

Claim Limit

DeviceID

Device ID

EN

European Norm

ESD

Emergency Shutdown Systems

ESPE

Electro-sensitive Protective Equipment

HFT

Hardware Fault Tolerance

HIM

Human Interface Module

IEC

International Electrotechnical Commission

IGBT

Insulated Gate Bipolar Transistors

ISO

International Organization for Standardization

NC

Normally Closed

NO

Normally Open

OSSD

Output Signal Switching Device

PELV

Protective Extra Low Voltage

PFD

Probability of a Dangerous Failure on Demand

PFH

Average Frequency of a Dangerous Failure per hour The average frequency of a system to have a dangerous failure per hour.

PL

Performance Level

PM

Permanent Magnet

SELV

Safety Extra Low Voltage Circuit

SIL

Safety Integrity Level

SSN

Safety Network Number

STO

Safe Torque Off

8

Table 1

defines the abbreviations that are used in this manual.

Definition

Refers to the behavioral design of a dual-channel safety system.

Classification of the safety-related parts of a control system in respect of their resistance to faults and

their subsequent behavior in the fault condition, and which is achieved by the structural arrangement

of the parts, fault detection, and/or by their reliability (source ISO 13849).

The maximum SIL rating that can be claimed for a safety-related electrical control system subsystem in

relation to architectural constraints and systematic safety integrity (source IEC 62061).

A unique identifier, comprised of the module number and SNN, to make sure that duplicate module

numbers do not compromise communication between the correct safety devices.

The official European Standard.

A system, usually independent of the main control system, which is designed to safely shut down an

operating system.

An assembly of devices and/or components working together for protective tripping or presence-

sensing purposes and includes as a minimum:

• A sensing device.

• Controlling/monitoring devices.

• Output signal-switching devices (OSSD).

The HFT equals n, where n+1 faults could cause the loss of the safety function. An HFT of one means

that two faults are required before safety is lost.

A module that is used to configure a device.

The International Electrotechnical Commission (IEC) is the organization that prepares and publishes

international standards for all electrical, electronic, and related technologies.

Typical power switch that is used to control main current.

The International Organization for Standardization is an international standard-setting body that is

composed of representatives from various national standards organizations.

A set of contacts on a relay or switch that are closed when the relay is de-energized or the switch is de-

activated.

A set of contacts on a relay or switch that are open when the relay is de-energized or the switch is de-

activated.

The component of the electro-sensitive protective equipment (ESPE) connected to the control system

of a machine. When the sensing device is actuated during normal operation, the device responds by

going to the OFF-state.

An electrical system where the voltage cannot exceed ELV under normal conditions, and under single-

fault conditions, except earth faults in other circuits.

The average probability of a system to fail to perform its design function on demand.

EN ISO 13849-1 safety rating

In permanent magnet (PM) motors, magnets mounted on or embedded in the rotor, couple with the

current-induced internal magnetic fields of the motor generated by electrical input to the stator.

A secondary circuit that is designed and protected so that, under normal and single fault conditions, its

voltages do not exceed a safe value.

A measure of a products ability to lower the risk that a dangerous failure could occur.

A unique number that identifies a section of a safety network.

The Safe Torque Off (STO) function is used to help prevent unexpected motor rotation during an

emergency while the drive remains connected to the power supply. When STO is activated, the torque

power cannot reach the drive, which stops and helps prevent any motor shaft rotation.

Rockwell Automation Publication 750-UM004B-EN-P - October 2018