Programmable Safety Controller SCR P
194
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16 Glossary
Automatic Reset
The safety input device control operation setting where the
assigned safety output will automatically turn on when all of its
associated input devices are in the Run state.
Change of State (COS)
The change of an input signal when it switches from Run-to-Stop
or Stop-to-Run state.
Closed-Open Debounce Time
Time to bridge a jittery input signal or bouncing of input contacts
to prevent nuisance tripping of the Controller. Adjustable from 6
ms to 100 ms. The default value is 6 ms (50 ms for mute
sensors).
Complementary Contacts
Two sets of contacts which are always in opposite states.
Concurrent (also Concurrency)
The setting in which both channels must be off at the same time
before turning back on. If this is not satisfied, the input will be in a
fault condition.
Designated Person
A person or persons identified and designated in writing, by the
employer, as being appropriately trained and qualified to perform
a specified checkout procedure.
Diverse-Redundancy
The practice of using components, circuitry or operation of
different designs, architectures or functions to achieve
redundancy and to reduce the possibility of common mode
failures.
Dual-Channel
Having redundant signal lines for each safety input or safety
output.
DCD
The In-Series Diagnostics (DCD) communication protocol
provides performance and status information from each
device in a chain to the PLC and/or HMI. Notification is sent
for the opening or closing of a door, mismatched or
misaligned sensors and actuators, and a range of additional
system health attributes.
Fault
A state of a device characterized by the inability to perform a
required function, excluding the inability during preventive
maintenance or other planned actions, or due to lack of external
resources. A fault is often the result of a failure of the device itself,
but may exist without prior failure.
Hard (Fixed) Guard
Screens, bars, or other mechanical barriers affixed to the frame of
the machine intended to prevent entry by personnel into the
hazardous area(s) of a machine, while allowing the point of
operation to be viewed. The maximum size of the openings is
determined by the applicable standard, such as Table O-10 of
OSHA 29CFR1910.217, also called a "fixed barrier guard."
Machine Response Time
The time between the activation of a machine stopping device
and the instant when the dangerous parts of the machine reach a
safe state by being brought to rest.
Manual reset
The safety input device control operation setting where the
assigned safety output will turn On only after a manual reset is
performed and if the other associated input devices are in their
Run state.
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