Banner MMD-TA-11B Muting Modules - Manual (Page 16)

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P/N 116390 rev. C
Banner Engineering Corp. • Minneapolis, U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
MMD-TA-11B / MMD-TA-12B Muting Module
Instruction Manual
System Installation
3.1.4 Pass-Through Hazards
A “pass-through hazard” is associated with applications where
personnel may pass through a safeguard (at which point the
hazard stops or is removed), and then may continue into the
hazardous area. Subsequently, their presence is no longer
detected, and the safeguard can not prevent the start or restart
of the machine. The related danger is the unexpected start or
restart of the machine while personnel are within the hazardous
area.
In the use of safety light screens, a pass-through hazard
typically results from large separation/safety distances calculated
from long stopping times, large defined area resolution, reach
over, reach through, or other installation considerations. A
pass-through hazard can be generated with as little as 75 mm
(3") between the defined area and the machine frame or hard
guarding.
Reducing or Eliminating Pass-Through Hazards
Measures must be taken to eliminate or reduce pass-through
hazards. One solution is to ensure that personnel are
continually sensed while within the hazardous area. This can be
accomplished by using supplemental safeguarding, including:
safety mats, area scanners, and horizontally mounted safety
light screens. While it is recommended to eliminate the pass-
through hazard altogether, this may not be possible due to cell
or machine layout, machine capabilities, or other application
considerations.
An alternate method is to ensure that once the safeguarding
device is tripped it will latch, and require a deliberate manual
action to reset. This type of supplemental safeguarding relies
upon the location of the reset switch as well as safe work
practices and procedures to prevent an unexpected start or
restart of the guarded machine.
The reset switch or actuating control must be positioned outside
the guarded area, and provide the switch operator with a full
unobstructed view of the entire guarded area and any associated
hazards as the reset is performed. The reset switch or actuating
control must not be reachable from within the guarded area and
must be protected (through the use of rings or guards) against
unauthorized or inadvertent operation. A key-actuated reset
switch provides some operator control, as it can be removed
by the operator 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 safeguarded area unnoticed.
The reset of a safeguard must not initiate hazardous motion.
Also, before each reset of the safeguard is performed, safe
work procedures require that a start-up procedure be followed
and that the individual performing the reset verify that the entire
hazardous area is clear of all personnel. If any areas can not be
observed from the reset switch location, additional supplemental
safeguarding must be used: at a minimum, visual and audible
warnings of machine start-up.
WARNING . . . Pass-Through Hazards,
Presence-Sensing Safeguarding
Devices, and Muting
If the presence-sensing safeguarding device
(PSSD) is guarding an application in which personnel
have access into the sensing area or field (for example,
a machine operator at the point of operation) while
the PSSD is muted, all pass-through hazards must be
eliminated. The individual must be sensed continually
while in the safeguarded area; this will prevent initiation
of a machine cycle if the mute ends while the individual is
within the hazardous area. See Appendix B for examples.
If the pass-through hazard cannot be eliminated, as in
entry/exit applications, the individual must be detected
entering the safeguarded area and the hazardous motion
must stop immediately.
3.2 Installing the Module
The Muting Module mounts to a standard 35 mm DIN-rail track.
The Module must be installed inside an enclosure rated NEMA 3
(IEC IP 54) or better. It can be mounted in any orientation. It
must be used with a properly installed and applied safeguard
(e.g., safety light screen, interlocked barrier guard). The user
must comply with all instructions contained within product
manuals and relevant regulations.
For reliable operation, the user must ensure that the operating
specifications are not exceeded. The enclosure must provide
adequate heat dissipation, so that the air closely surrounding the
Module does not exceed its maximum operating temperature.
Methods to reduce heat build-up include venting, forced air flow
(e.g., exhaust fans), adequate enclosure exterior surface area,
and spacing between Modules and other sources of heat. (See
Specifications, “Operating Conditions.”)
Mount the Module in a convenient location that is free from
heavy impulse force and high-amplitude vibration.
Electrostatic Discharge (ESD) can cause damage to electronic
equipment. To prevent this, follow proper ESD handling
practices such as:
• Wear an approved wrist strap or other approved grounding
products.
• Touch a grounded object before handling the Module.
See ANSI/ESD S20.20 for further information about managing
ESD.