Rockwell Automation Allen-Bradley 35E, Руководство пользователя

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Rockwell Automation Publication 35-UM001A-EN-P - May 2022 131
Chapter 6 Safety Functions
Safety Output Features
• Current sourcing/current sinking-bipolar pair
• Dual-channel mode provides redundant control by using two output
signals (channels), which allows use of the module for safety Category 4,
and 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.
• Safety output can be pulse tested to detect field wiring short circuits to
24V DC.
• Safety output can be configured for SBC or control via the safety output
assembly
Dual-channel Mode (Safety Outputs)
When the data of both channels is in the on state, and neither channel has an
alarm, the outputs are turned on. The status is normal. If an alarm is detected
on one channel, the safety output data and individual safety output status turn
off for both channels.
Figure 66 shows the operation of dual channel outputs under normal and
alarm conditions.
Figure 66 - Dual-channel Setting (Not to Scale)
In dual-channel mode, the output latch error time describes the period
between when the alarm condition is removed and when the dual channel
safety output stops reporting the alarm.
Figure 67 shows the normal operation
of output latch error time in dual channel mode. When one or both of the
associated output points have an alarm (such as a Pulse Test Failure), and there
is a discrepancy between the two channels, the alarm and discrepancy must be
cleared before the latch error timer begins counting.
Figure 68 shows this
special case operation. See Safety Input or Output Fault Recovery on page 136
for information on how to remove an alarm.
ON
OFF
Safety Output 0
Normal Operation
ON
OFF
Safety Output 1
ON
OFF
Dual Channel
Output Status
Alarm Operation
ON
OFF
Safety Output 0
Value
ON
OFF
Safety Output 1
Value
ON
OFF
Dual Channel
Output Status
Alarm Detected