industrial storage carousel operator protection

1. Photoelectronic sensors are of key importance today when the
goal is to detect or monitor objects without touching them; they
are used wherever e.g. positioning, classification or counting is
required.
The applications range from the automobile industry, machine
design, and assembly automation to warehousing and conveyor
systems, packaging machines, surveillance and safety technology
For applications in which a on-beam optical detector is enough,
there is wide spectrum of light grids available; they are used for
the profile control of boxes, pallets, monitoring of lift doors
and much more.
The law prescribes protective measures wherever a machine in
normal operation or the occurence of one or several errors might
cause pose a hazard to people or equipment.
These measures are based on European law (Directive
89/392/EC) and the Machinery Directive; risk assessment
according to EN 1050 (ISO 14121 A standard) evaluates the
complete or partial loss of the safety function, which is caused by
errors. The basic idea of the European safety standardisation is to
determine the risk of plant or a machine. This risk assessment is
based on EN 1050, typical hazards include:
- Mechanical hazards
- S Severity of the injury
- S1 Slight (usually reversible) injury
- S2 Serious (usually irreversible) injury, including death
- F Frequency and/or duration of the exposure to hazard
- F1 Rarely to more often and/or short duration of the exposure
- F2 Frequently to continuously and/or long duration of the
exposure
- P Possibility to avoid the hazard
- P1 Possible under certain conditions
- P2 Hardly possible
- Burns
Depending on the results of this analysis, the plant or machine is
assigned to a certain category. This has the advantage that the
requirements on the safety system and its costs can be adpated to
the actual risk; moreover, the assessment of a category depends
on the area of application.
For the process industry, for instance, different classifications
apply than for machine engineering.