Banner MMD-TA-11B Muting Modules - Manual (Page 53)

P/N 116390 rev. C
51
Banner Engineering Corp. • Minneapolis, U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
MMD-TA-11B / MMD-TA-12B Muting Module
Instruction Manual
Appendix B
Power Press Applications
Muting is allowed on power presses only during the non-
hazardous portion of the cycle (e.g. the upstroke), per
OSHA1910.217, ANSI B11.1, B11.2, and B11.3. The mute
permits the insertion or removal of material into the press
that would otherwise block the sensing field of the safety
light screen, causing the press to stop. Muting should not be
confused with “Inch” or “Jog” modes, whose manual selection
may bypass the safety light screen within the machine control.
For the proper application of muting on a power press, at a
minimum, two (or four) independent position switches (such as
cam-operated limit switches, inductive prox sensors, or pressure
switches) must be used to initiate the mute during the non-
hazardous portion of the machine cycle. These position switches
would be mute devices M1/M2 (and M3/M4 if used). Typically,
these switches have normally open contacts, which are held (or
actuated) closed during the mute cycle.
These switches must be mounted separately to prevent
misadjustment, misalignment, or a single common mode failure,
which would result in an improper mute cycle or otherwise
unsafe condition. They must be installed so that they can not
be easily defeated or bypassed, and their adjustment should be
under supervisory control.
The two (or four) muting devices must be properly adjusted (or
positioned) so that they close only after the hazard no longer
exists and then open when the cycle is complete (top of stroke)
or when the hazard is again present. If improperly adjusted or
positioned, injury or death could result.
If the machine has reversing capability where a hazard is
possible during a muted condition, the control must include
an automatic means through which muting is permitted in the
forward (non-hazardous) direction only. A “Mute Enable” signal
from the machine control, motor drive, or other machine logic, is
a means to assist in meeting this requirement.
WARNING . . . Proper Installation
The user has the responsibility to ensure that
all local, state, and national laws, rules, codes,
and regulations in any particular application
are satisfied. It is extremely important to be sure that all
appropriate agency requirements have been met. See inside
back cover for appropriate standards.
In muting applications involving an operator, all pass-through
hazards must be eliminated so that the operator is continually
detected when in the defined area. This ensures that if a
hazard arises, causing the mute cycle to end while the operator
is present, the safety light screen will immediately issue a
stop. (See pass-through hazard information below.)
A “pass-through hazard” is associated with applications that
allow personnel to pass through a safeguard, which removes or
stops the hazard(s), and then allows the individual to continue
into the hazardous area. Subsequently the individual’s presence
is no longer detected, and the safeguard can not prevent the
start or restart of the machine. A pass-through can be created
by as little as 75 mm (3") space between the defined area and
machine frame. If the safety light screen is muted while the
individual passes through the defined area, a stop command will
not be issued and the hazard cannot be eliminated; the individual
must be detected while entering the safeguarded area and
the hazardous motion must stop immediately. This is typically
accomplished by supplemental safeguarding such as described
in ANSI B11 standards or other appropriate standards.