Banner MM-TA-12B Instruction Manual page 26

System Installation
3.5.5.2 USSI/MSSI Interlocked Safety Gate Hookup
The USSI (or MSSI) may be used to monitor interlock safety gates or guards.
Requirements vary widely for the level of control reliability or safety category per
ISO 13849 (EN954-1) in the application of interlocked guards. While Banner
Engineering always recommends the highest level of safety in any application, it
is the responsibility of the user to safely install, operate and maintain each safety
system and comply with all relevant laws and regulations. Of the following two
applications, Figure 3-13 meets or exceeds the requirements for OSHA control
reliability and Safety Category 3 or 4, per ISO 13849 (EN954-1).
Safety Interlocking Switch Requirements
The following general requirements and considerations apply to the installation of
interlocked gates and guards for the purpose of safeguarding. In addition, the
user must refer to the relevant regulations to be sure to comply with all neces-
sary requirements.
Hazards guarded by the interlocked guard must be prevented from operating until
the guard is closed; a stop command must be issued to the guarded machine if
the guard opens while the hazard is present. Closing the guard must not, by
itself, initiate hazardous motion; a separate procedure must be required to initiate
the motion. The safety switches must not be used as a mechanical or end-of-
travel stop.
The guard must be located an adequate distance from the danger zone (so that
the hazard has time to stop before the guard is opened sufficiently to provide
access to the hazard), and it must open either laterally or away from the hazard,
not into the safeguarded area. The guard also should not be able to close by itself
and activate the interlocking circuitry. In addition, the installation must prevent
personnel from reaching over, under, around or through the guard to the hazard.
Any openings in the guard must not allow access to the hazard (see OSHA
29CFR1910.217 Table O-10 or the appropriate standard). The guard must be
strong enough and designed to protect personnel and contain hazards within the
guarded area, which may be ejected, dropped or emitted by the machine.
The safety interlocking switches and actuators used with the MM-TA-12B Muting
Module must be designed and installed so that they cannot be easily defeated.
They must be mounted securely, so that their physical position can not shift,
using reliable fasteners that require a tool to remove them.
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MM-TA-12B Muting Module
Instruction Manual
WARNING . . .
Hard Guarding
It must not be possible
for personnel to reach any hazard
point through an opened guard (or
any opening) before hazardous
machine motion has completely
stopped.
Please reference OSHA CFR
1910.217 and ANSI B11 standards
(see Appendix C) for information on
determining safety distances and
safe opening sizes for your guard-
ing devices.