Terminology – Rockwell Automation 21G PowerFlex 750-Series AC Drives Reference Manual User Manual
Page 12

12
Rockwell Automation Publication 750-RM001F-EN-P - February 2012
Preface
Terminology
This table defines abbreviations used in this manual.
Abbreviation
Full Term
Definition
1oo2
One out of Two
Refers to the behavioral design of a dual-channel safety system.
CAT
Category
—
CL
Capability Level
—
DC
Door Control
—
DM
Door Monitoring
—
EN
European Norm
The official European Standard.
ESD
Emergency Shutdown Systems
—
ESM
Enabling Switch Monitoring
—
ESPE
Electro-sensitive Protective Equipment
An assembly of devices and/or components working together for protective tripping or presence-
sensing purposes and comprising as a minimum:
• a sensing device.
• controlling/monitoring devices.
• output signal-switching devices (OSSD).
FMEA
Failure Mode and Effects Analysis
—
FV
Flux Vector
—
HFT
Hardware Fault Tolerance
The HFT equals n, where n+1 faults could cause the loss of the safety function. An HFT of 1 means that
2 faults are required before safety is lost.
HIM
Human Interface Module
A module used to configure a device.
IEC
International Electrotechnical Commission
—
IGBT
Insulated Gate Bi-polar Transistors
Typical power switch used to control main current.
ISO
International Organization for Standardization
—
LM
Lock Monitoring
—
MP
Motion Power
—
NC
Normally Closed
A set of contacts on a relay or switch that are closed when the relay is de-energized or the switch is de-
activated.
NO
Normally Open
A set of contacts on a relay or switch that are open when the relay is de-energized or the switch is de-
activated.
OSSD
Output Signal Switching Device
The component of the electro-sensitive protective equipment (ESPE) connected to the control system
of a machine, which, when the sensing device is actuated during normal operation, responds by going
to the OFF-state.
PC
Personal Computer
Computer used to interface with and program your safety system.
PELV
Protective Extra Low Voltage
An electrical system in which the voltage cannot exceed ELV under normal conditions, and under
single-fault conditions, except earth faults in other circuits.
PFD
Probability of Failure on Demand
The average probability of a system to fail to perform its design function on demand.
PFH
Probability of Failure per Hour
The probability of a system to have a dangerous failure occur per hour.
PL
Performance Level
ISO 13849-1 safety rating
PM
Permanent Magnet
—
PTI
Proof Test Interval
—
SDM
Safe Direction Monitoring
—
SELV
Safety Extra Low Voltage Circuit
A secondary circuit which is so designed and protected that, under normal and single fault conditions,
its voltages do not exceed a safe value.
SFF
Safe Failure Fraction
The sum of safe failures plus the sum of dangerous detected failures divided by the sum of all failures.
SIL
Safety Integrity Level
A measure of a products ability to lower the risk that a dangerous failure could occur.
SLS
Safe Limited Speed
—
SMA
Safe Maximum Acceleration
—
SMS
Safe Maximum Speed
—
SS
Safe Stop
—