The reset switch must be mounted at a location that complies with the warning and guidelines below. If any hazardous
areas are not in view from the switch location, additional means of safeguarding must be provided. The switch should be
protected from accidental or unintended actuation (for example, through the use of rings or guards).
A key-actuated reset switch provides some operator or supervisory control, as the key can be removed from the switch and
taken into the guarded area. However, this does not prevent unauthorized or inadvertent resets due to spare keys in the
possession of others, or additional personnel entering the guarded area unnoticed. When considering where to locate the
reset switch, follow the guidelines below.
WARNING: Reset Switch Location
When considering where to locate the reset switch, you must follow the guidelines outlined in this
section.
If any areas within the guarded area are not visible from the reset switch, additional safeguarding must
be provided, as described by the ANSI B11.19 series or other appropriate standards.
Failure to follow these instructions could result in serious injury or death.
All reset switches must be:
• Outside the guarded area
• Located to allow the switch operator a full, unobstructed, view of the entire guarded area while the reset is
performed
• Out of reach from within the guarded area
• Protected against unauthorized or inadvertent operation (such as through the use of rings or guards).
Important: Resetting a safeguard must not initiate hazardous motion. Safe work procedures require a start-up
procedure to be followed and the individual performing the reset to verify that the entire hazardous area is clear of all
personnel before each reset of the safeguard is performed. If any area cannot be observed from the reset switch
location, additional supplemental safeguarding must be used: at a minimum, visual and audible warnings of machine
start-up.
5.1.5 Adjacent Reflective Surfaces
WARNING: Avoid Installation Near Reflective Surfaces
Avoid locating the sensing field near a reflective surface; it could reflect sensing beam(s) around an
object or person within the sensing field, and prevent its detection by the EZ-SCREEN LS Basic. Perform
the trip test, as described in the manual, to detect such reflection(s) and the resultant optical short
circuit. Failure to prevent reflection problems will result in incomplete guarding and could result in serious
injury or death.
A reflective surface located adjacent to the defined area may deflect one or more beams around an object in the defined
area. In the worst case, an optical short circuit may occur, allowing an object to pass undetected through the defined area.
This reflective surface may result from shiny surfaces or glossy paint on the machine, the workpiece, the work surface, the
floor, or the walls. Beams deflected by reflective surfaces are discovered by performing the trip test and the periodic
checkout procedures. To eliminate problem reflections:
• If possible, relocate the sensors to move the beams away from the reflective surface(s), being careful to maintain
adequate separation distance
• Otherwise, if possible, paint, mask, or roughen the shiny surface to reduce its reflectivity
• Where these are not possible (as with a shiny workpiece or machine frame), determine the worst-case resolution
resulting from the optical short circuit and use the corresponding depth penetration factor (Dpf or C) in the Safety
Distance (Minimum Distance) formula; or mount the sensors in such a way that the receiver's field of view and/or the
emitter's spread of light are restricted from the reflective surface
• Repeat the trip test (see
Trip Test
on page 35) to verify these changes have
eliminated the problem reflection(s). If the workpiece is especially reflective and comes close to the defined area,
perform the trip test with the workpiece in place
EZ-SCREEN
®
LS Basic Safety Light Screen
24
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