Rockwell Automation Publication 35-UM001A-EN-P - May 2022
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Chapter 6 Safety Functions
Safe State
The following are the safe states of the Armor PowerFlex safety I/O:
•
Safety outputs from network data: OFF (single channel and dual channel
equivalent)
•
Safety input data to network: OFF (single channel and dual-channel
equivalent)
•
Safety input data to network: OFF/ON for input channels n/n+1 (dual-
channel complimentary, See
Dual Channels, Complementary on page 123
for additional details)
The safety I/O is designed for use in applications where the safe state is the off
state.
Safety Input Features
•
Safety devices, such as emergency stop push buttons, gate switches, and
safety light curtains, can be connected.
•
Dual-channel mode evaluates consistency between two input signals
(channels), which allows use of the module for safety Category 3 and 4
and in applications that are rated up to and including Performance
Level e/SIL 3 when both channels’ Point Mode configurations are set to
Safety Pulse Test.
•
Single-channel mode evaluates one input signal (channel), which allows
use of the module for safety Category 2 and in applications that are rated
up to and including Performance Level d/SIL 2 when the channel's Point
Mode configuration is set to Safety Pulse Test.
•
You can configure a discrepancy time to control how long two channels
are allowed to be discrepant before a fault is declared.
•
An external wiring short-circuit check is possible when inputs are wired
in combination with test outputs. The drive must be wired in
combination with test outputs when this function is used.
•
Independently adjustable on- and off-delays are available per channel.
•
Separate test outputs are provided for short-circuit detection of a safety
input or inputs.
• Power (24V) can be supplied to devices, such as safety sensors.
• Test outputs can be configured as standard outputs.
Safety Input Operation
Safety inputs are used to monitor a safety input device and can be configured
as single or dual channel inputs. They also support configuration of on- and
off-delay times. A configurable latch error time allows you to specify the
minimum amount of time that a safety input alarm is reported.
Single-channel Mode (Safety Inputs)
The next paragraph describes the status and value that the I/O subsystem
reports for normal and alarm states. In normal operation, the I/O value that is
reported is the value being read on the input terminal. The I/O status is on.
When a fault is detected, the Safety Input value and status are forced Off.
The safety input subsystem allows for a configurable time for which an alarm
state is held, which is referred to as Input Latch Error Time. In single channel
mode, the input latch error time describes the period between when the alarm
condition is removed and when the safety input stops reporting the alarm.
