Allen-Bradley GuardPLC 1753, Справочник по безопасности

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Publication 1753-RM002C-EN-P - September 2008 47
GuardPLC Controller and GuardPLC I/O Output Channels Chapter 4
Negative-switching Outputs (DO-)
If a output fault is detected, the affected output of the module is set to
a safety, de-energized state via the safety switches. In case of a
module fault, all outputs are switched off. Both faults are indicated via
the FAULT LED indicator.
Positive-switching Outputs (DO+)
If an output fault is detected, the affected output of the module is set
to a safety, de-energized state via the safety switches. In case of a
module fault, all outputs are switched off. Both faults are indicated via
the FAULT LED indicator.
External Short Circuit or Overload Performance
If the output is short-circuited to L-, L+, or an overload condition
exists, it is still possible to carry out tests on the module. A safety
shutdown is not required.
The total current consumption of the module is monitored. If the
threshold is exceeded, all the channels of the output module are set to
the safety 0 state.
In this state the outputs are cyclically checked (in periods of several
seconds) if the overload is still present. Once the short-circuit or
overload condition is corrected, the outputs are activated according to
the application program.
2-pole Digital Outputs in 1753-IB8XOB8 and 1753-IB16XOB8 Modules
& &
& &
Logic
Current
Limiter
Connection
to an I/O
bus
Current Limiter
Logic
2-pole Output
WD
DOx+
DOx-
WD
L+
L-
DO1+
DO1-
S+
S-
(1)
(1)
(1) switch only on 1753-IB8XOB8
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