Table of Contents
Preface
8
• GuardLink Safety Signal - A known dynamic safety signal in
operational mode and a two-way communication signal that the DG
safety relay initiates to determine the status of the taps in the safe state.
• HI - The ON state of the output of a logic block or the state of an input
to a logic block or a voltage level to be above the turn-on threshold.
• LO - Logic state of being OFF or a voltage level to be below the turn-off
threshold.
• N/C - No connection
• N.C. (Normally Closed) - A voltage-free electrical contact whose
normal state (that is, no pressure or electrical potential applied) is in the
closed position.
• N.O. (Normally Open) - A voltage-free electrical contact whose
normal state (that is, no pressure or electrical potential applied) is in the
open position.
• Output Signal Switching Device (OSSD)- Generally a pair of solid-
state signals that are pulled up to the DC source supply. The signals are
pulse-tested for short circuits to the DC power supply, short circuits to
the DC common and shorts circuits between the two signals.
• Reaction Time - The time between the true states of one input to the
ON state of the output.
• Recovery Time - The time that is required for the input to be in the LO
state before returning to the HI state.
• Response Time - The time between the trigger of one input to the OFF
state of the output.
• Safety Function - The complete process from sensing the action (for
example, open a safety gate) to executing the final output device (for
example, turning off a pair of contactors).
• Single Wire Safety (SWS) - A unique unidirectional safety-rated signal
that is sent over one wire to indicate a safety status and command the
initiation of a safety function. The SWS can be used in Category 4,
Performance Level e, per ISO 13849-1 and safety integrity level (SIL) 3,
per IEC 62061 and IEC 61508.
• Status Indicators - The status indicators on the front face of the DG
safety relay and the taps are bicolor.
indicators are used in this publication.
Table 1 - Status Indicator State
Symbol
Description
Green indicator is OFF
Red indicator is OFF
Green indicator is OFF
Red indicator is ON
Green indicator is OFF
Red indicator flashes with certain
frequency
Green indicator is ON
Red indicator is OFF
Rockwell Automation Publication 440R-UM015C-EN-P - April 2018
Table 1
shows how the status
Symbol
Description
Green indicator flashes with certain
frequency
Red indicator is OFF
Green indicator is ON
Red indicator is ON
Green indicator flashes with certain
frequency
Red indicator flashes with certain
frequency
Table of Contents
