Banner AG4 Series - Needle- and Cone-Shaped Protective Field Contours

Banner AG4 Series Safety Laser Scanner
3.3.2 Needle- and Cone-Shaped Protective Field Contours
CAUTION . . . NEEDLE- AND CONE-SHAPED PROTECTIVE FIELD CONTOURS
Any safety distance calculations must consider and resolve the effects of needle- or cone-shaped Protective Fields. Boundaries or
contours that rely on too few measurement points (e.g., one or two) may not reliably turn OFF the OSSDs when an object is present.
Needle- and cone-shaped Protective Field boundaries are not recommended, because they may not reliably
detect and respond to objects (i.e., turn OFF the OSSDs), compared with smooth-field boundaries made up of multiple
measurement points. Two effects are to be considered:
1. Not identifying the proper size of the detected object (outward cone shapes), and
2. An increase in resolution (inward cone shapes).
Outward Needle- and Cone-Shaped Field Contours
An object equal to or greater than the stated resolution (e.g., 70 mm) will be detected at point A (Object 1) in Figure 3-4,
because enough sensing points are present at that location to detect the full 70 mm size of the object.
Objects 2 or 3 may not be identified as being larger than the resolution because at that distance, the angle is too narrow
(and has too few sensing points) to detect the full 70 mm resolution size.
Inward Needle- and Cone-Shaped Field Contours
The effect of an inward cone-shape is to increase the effective resolution immediately adjacent to the shape. For the
Scanner to identify that an object is equal to or greater than the stated resolution (e.g., 70 mm), the entire object must be
within the Protective Field to turn OFF the OSSDs (e.g., Object 4). When an object enters the unmonitored cone-shaped
area, the start/restart inhibit function will enable a reset as soon as the object portion within the Protective Field is
smaller than the stated resolution (Objects 5 and 6). This will turn ON the OSSDs if the configuration is set to ―automatic
start/restart (auto reset)‖, or if the reset switch is actuated.
To prevent a safety distance that is too short at that point, the increased effective resolution must be used to determine
the Dpf or C factor in the respective safety distance formulas (see Sections 3.3.4 and 3.3.5). If a cone-shaped field must
be used and the safety distance cannot be complied with, additional supplemental safeguarding must be used. Refer
also to the previous section, ―Shadowing Within the Protective Field,‖ for more information.
To verify Protective Field effectiveness, perform a trip test (see Section 3.6.3).
Figure 3-4. Example of inward and outward cone-shaped fields
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