Figure 8. Vertical guarding with reference contour monitoring
Typical considerations for vertical guarding:
• In the example shown, the objective is to prevent an individual from entering an area; detecting the body (torso) is
required.
• In this example, physical damage is not expected because the SX5 is mounted above and away from the probable
path of the forklift. If impact is possible, a mechanical guard/shroud can be added to protect the SX5 without
blocking the Safety Zones.
• The typical manufacturing setting is well within the SX5's environmental ratings.
• The size and coverage of the Safety Zone must ensure that unrestricted or accidental entry to the work cell is
prevented. Two SX5s are used to create four Safety Zones to cover each end of the pallet load/unload station (e.g.
left side SZ, right side SZ, and both sides SZ). When no pallets are at the station, the front SX5 has a Safety Zone
that covers both sides; the rear SX5 can be muted to allow pallets to be fed into the station (such as pallets exiting
the cell). As pallets are loaded, sensors monitoring the pallet position switch the Zone Sets to "turn off" the front
Scanner's right side and "turn on" (and unmute) the rear SX5's Safety Zone for that side (as shown). This allows the
forklift to pick up the pallet and remove it.
• When the front Safety Zone is inactive, the pallet must completely block the opening to prevent access. When the
pallet is removed, that Safety Zone must immediately be re-activated.
• The use of the Reference Points is required for vertical guarding applications (e.g. the blue points).
• In this example, no factors would require an increase in the safety distance.
• For this example, assume a machine stopping time of 200 ms, SX5 response time of 62 ms; safety interfacing
device (UM-FA-9A safety module) response time is 25 ms. The resolution can be either 40 or 70 mm, since only
body detection 70mm can be selected, the Dpf adder is equal to 900 mm (U.S. formula). This gives a safety distance
of: Ds = 1600 mm/s x (0.2s + 0.062s + 0.025s) + 900 mm = 1359 mm (53.5 in). In other words, the plane of the rear
Protective Field must be no closer than 1359 mm (53.5 in) from the nearest hazard (assuming no hazard inside the
load station).
• Configure the SX5 for start/restart interlock (manual reset) to ensure that if an individual interrupts an active Safety
Zone while attempting to enter the guarded area that the SX5's OSSD safety outputs remain OFF until manually
reset after the individual exits the cell.
• For the purpose of this example, the UM-FA-9A Universal Input Safety Module was used and interfaced in a control
reliable (category 3 or 4) method as described by Section 3 and Figure 3-19.
Mobile Area Guarding with Side Vertical Guarding
Vertically guarding the sides of transfer carts, material-handling trolleys, and Automated Guided Vehicles (AGVs) prevents
contact with objects that may have overrun the stop position of a conveyor, which could result in damage to the mobile
vehicle and the conveyor. This type of guarding can also be used for situations that with a crushing/trapping hazard, for
example, a distance less than 500 mm (20 in) between the sides of the SX5 and a physical structure.
Two SX5s are positioned to create horizontal Safety Zones, to prevent running over objects or individuals in the path of the
vehicle. A second pair of vertically mounted SX5s is positioned to detect objects at or above the horizontal plane of the
SX5s that are looking ahead of, and behind the vehicle. In this configuration, the "leading edge" of the Safety Zone is now
provided by the vertical edges on the sides of the SX5. These edges will detect the torso of an individual; 70 mm resolution
is typically selected.
SX5 Safety Laser Scanner
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