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Muting module
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MM-TA-12B Muting Module
Instruction Manual
WARNING . . .
Avoid Hazardous
Installations
Two or four independent position
switches (at M1-M2 or M3-M4)
must be properly adjusted or posi-
tioned so that they close only after
the hazard no longer exists, and
open again when the cycle is com-
plete or the hazard is again pres-
ent. If improperly adjusted or posi-
tioned, injury or death could
result.
The user has the responsibility to
satisfy all local, state, and national
laws, rules codes, and regulations
relating to the use of safety equip-
ment in any particular application. It
is extremely important to be sure
that all appropriate agency require-
ments have been met and that all
installation and maintenance
instructons contained in the appro-
priate manuals are followed.
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sources. These sources must be mounted separately in order to prevent an
unsafe muting condition resulting from misadjustment, misalignment, or a sin-
gle common mode failure. (For example, physical damage to the mounting
surface could cause both muting devices to be knocked out of alignment,
resulting in false muting input signals.) Only one of these sources may pass
through, or be affected by, a programmable logic controller or similar device.
4) The muting devices must be installed so that they can not be easily defeated
or bypassed.
5) The muting devices must be mounted so that their physical position and align-
ment can not be easily changed.
6) It must not be possible for environmental conditions to initiate a mute condi-
tion (e.g., extreme airborne contamination).
7) The muting devices must not be set to use any delay or other timing functions
(unless such functions are accomplished so that no single component failure
prevents the removal of the hazard, subsequent machine cycles are prevented
until the failure is corrected, and no hazard is created by extending the muted
period).
3.5.2.2 Examples of Muting Sensors and Switches
Photoelectric Sensors (Opposed Mode)
Opposed-mode sensors, which initiate the muted condition when the beam path
is blocked, should be configured for dark operate and have open (non-conduct-
ing) output contacts in a power OFF condition.
Photoelectric Sensors (Polarized Retroreflective Mode)
The user must ensure that false "proxing" (activation due to shiny or reflective
surfaces) is not possible. Banner "LP" sensors with linear polarization can greatly
reduce or eliminate this effect.
Configure sensors for Light Operate (LO or N.O.) if initiating a mute when the
retroreflective target or tape is detected (e.g., home position). Configure sensors
for Dark Operate (DO or N.C.) when a blocked beam path initiates the muted con-
dition (e.g., entry/exit). Both situations must have open (non-conducting) output
contacts in a power OFF condition.
Positive-Opening Safety Switches
Two (or four) independent switches, each with a minimum of one closed safety
contact to initiate the mute cycle are typically used. An application using a single
switch with a single actuator and two closed contacts could result in an unsafe
situation.
Inductive Proximity Sensors
Typically, inductive proximity sensors are used to initiate a muted cycle when a
metal surface is detected. Due to excessive leakage current causing false ON con-
ditions, two-wire sensors are not to be used. Only three- or four-wire sensors
that have discrete PNP, NPN, or hard-contact outputs that are separate from the
input power can be used.
System Installation

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