OFF state
The OFF state is the status of the outputs of the protective device,
where the controlled machine is triggered to quit its dangerous
state and the start-up of the machine is prevented (e.g., the volt‐
age at the OSSDs is LOW, so that the machine is switched off and
remains still).
ON state
The ON state is the status of the outputs of the ESPE, where the
controlled machine is permitted to operate (e.g., the voltage at the
OSSDs is HIGH so that the machine can run).
OSSD
Output signal switching device: signal output for the protective
device, which is used for stopping the dangerous movement.
An OSSD is a safety switching output. The functionality of each
OSSD is tested periodically. OSSDs are always connected in pairs
and must undergo dual-channel analysis for safety reasons. An
OSSD pair is formed from 2 OSSDs that are connected and ana‐
lyzed together.
PFHD
Probability of dangerous failure per hour
PL
Performance level (ISO 13849)
Protective field
The protective field protects the hazardous area of a machine or
vehicle. As soon as the electro-sensitive protective device detects
an object in the protective field, it switches the associated safety
outputs to the OFF state. This signal can be passed to controllers
resulting in the dangerous state coming to an end, e.g. to stop the
machine or the vehicle.
A horizontal or vertical protective field is required, depending on
the application. The electro-sensitive protective device can there‐
fore be mounted in horizontal or vertical alignment, depending on
the requirements.
Reference contour field
The contour as reference field monitors a contour of the environ‐
ment. The safety laser scanner switches all safety outputs to
the OFF state if a contour does not match the set parameters,
because, for example, the mounting of the safety laser scanner
has been changed.
National and international standards require or recommend that a
reference contour is monitored, if the safety laser scanner is used
in vertical operation for hazardous point protection or for access
protection.
GLOSSARY
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8017784/1ELL/2022-01-21 | SICK
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Subject to change without notice
