In perimeter safeguarding, devices such as the SICK M4000 Multiple Beam Perimeter Safety Device are used to detect workers entering a specific area. Once through the perimeter, a person is no longer detected, but the machine will not restart when the safeguard is cleared. Manual resets are almost always used with perimeter safeguards. The reset button is placed well outside the area safeguarded and is used after all workers have exited the area within the perimeter safeguard. After reset, the manual restart of the machine can be initiated.

Perimeter safeguards are appropriate for applications where machines work without operator intervention. For machines where operator intervention is vital (e.g., replacing or moving parts), a light curtain might be a more appropriate safeguard. (See note below about using a light curtain as a perimeter safeguard.)

Perimeter safeguarding uses lower resolution sensing, which can detect torsos as opposed to hands, fingers or arms. Given this, the Safety Distance (Dpf) increases. The optics of perimeter safeguards is specially designed for longer distances. As a general rule, perimeter safeguards are cost-effective. Some of the special features of perimeter safeguarding include multiside and entry/exit safeguarding.

Check out the SICK line of L4000 single-beam perimeter safety devices as well as the M4000 multi-beam safety devices.