Specifications

Presence Sensing Safety Devices
Selection Tips
2-3
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Publication S117-CA001A-EN-P
GeneralPrinciples
2-Selection
Criteria
Safety SwitchesOperator
Interface
LogicPower
R
Selection Tips
Is the hazardous area stationary or mobile?
What do we mean by full- versus partial-body access?
Object to be Detected/Protected Resolution
Finger (vertical field) 14 mm
Hand (vertical field) 30 mm
Limb (horizontal field for leg detection) 50 mm, 70 mm
Full Body (horizontal fields) 150 mm
Blind Spots
Is the shape of the hazardous area rectangular?
Other Application Considerations
Safety Mats Safety Scanner
Point of Operation
Control
Perimeter Access
Control
Partial Body Detection
Finger Detection 14 mm
Hand Detection 30 mm 30 mm
Limb Detection 50/70 mm
Full Body Detection
 
Uneven Floor

Horizontally Mounted
Corrosive Chemicals

High-Pressure Washdowns

IP67/IP69K Enclosure IP67 Enclosure
Steam, Dust Environment

Reflections, Bright Ambient Light

A stationary hazard refers to a fixed machine or work cell where one or more mechanical hazards exist. A mobile hazard is generally a fixed-
rail linear transfer mechanism (e.g., a transfer cart or conveyor) or an Automatic Guided Vehicle (AGV). Use of a safety device on a mobile
hazard generally relates to collision avoidance with personnel or surrounding machinery.
In the instance that the hazard moves toward the operator (such as with powered doors) as opposed to the operator moving toward the
hazard, a pressure-sensitive safety edge can be mounted to the leading edge of the door. Any contact between the door and personnel will
stop the machine before injury can occur.
Full-body access generally refers to the requirement for a person to be standing or walking in (or have access to) the hazardous area around
a machine that does not require frequent interaction between personnel and the hazard during regular operation; generally this is for
maintenance and troubleshooting. Full-body perimeter or area access control (PAC or AAC, respectively) is achieved through the use of a
vertical or horizontal safety field, either opto-electronic (i.e., a light curtain or scanner) or by contact (safety edges and mats).
Partial-body access, on the other hand, is required for applications where an operator must regularly reach into a machine hazard as part of
the process at the point of operation (known as POC or Point of Operation Control). In the case of opto-electronic safety devices such as
light curtains and area scanners, full- or partial-body detection is directly related to the resolution of the safety device. Below is the
relationship of sensing field resolution to the type of detection:
In some cases it may be possible for a person to enter the guarded area and be lost from view, potentially allowing the guard door to be shut
and the machine started by another person. Often used in conjunction with hard guarding and a gate outfitted with an interlock switch,
presence sensing safety devices such as pressure-sensitive safety mats, and laser scanners can be used to check for the presence of a
person anywhere within the enclosed safety area.
When the hazardous area to be monitored is a rectangle (or a shape consisting of contiguous rectangles), access to the area can be easily—
and cost-effectively—controlled with a standard safety mat. When the hazardous area is irregularly shaped, a custom mat is a viable option,
but not necessarily the most cost-effective or readily available. In such a case, a safety scanner is the best option because its scanning field
can be easily programmed to scan irregular areas and ignore obstacles (walls, columns) while detecting moving objects (people, AGVs, etc.)
as required.