product must be thoroughly familiar with all applicable standards, some of which are listed within the specifications.
Banner Engineering Corp. makes no claim regarding a specific recommendation of any organization, the accuracy or
effectiveness of any information provided, or the appropriateness of the provided information for a specific application.
Overview
Use the SI-LS83xxx Series Safety Limit (Position) Switches to monitor the position of a guard to detect the movement,
opening, or removal. A "guard" can be a gate, door, cover, panel, barrier or other physical means that separates an
individual from a hazard. Safety Switches will issue a signal to the machine control system to prevent or stop (halt)
hazardous situations when the guard is not in the proper position. These Safety Switches are designed for non-locking
guarding applications, unless another means of locking is provided.
The SI-LS83xxx Series Safety Limit (Position) Switches are considered a Type 1 interlocking device per ISO 14119 that are
mechanically actuated by an uncoded rotary or linear actuator (cam or "dog") typically mounted on or part of the guard. A
variety of actuating systems are available: plunger (dome), roller plunger, spindle-mount lever roller, and lever.
Installation 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 and comply with all necessary
requirements. See ANSI B11.19, or ISO 14119 and ISO 14120, or the appropriate standard.
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.
Locate the guard an adequate distance from the danger zone (so the hazard has time to stop before the guard is opened
sufficiently to provide access to the hazard). Guard locking or supplemental safeguarding must be used if the overall
stopping time of the machine or the time to remove the hazard is greater than the time to access the guarded area. The
guard 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. The installation must prevent personnel from reaching over,
under, around or through the guard to access the hazard. Any openings due to positioning, movement, or misalignment in
the guard must not allow access to the hazard—see ANSI B11.19, ISO 13855, ISO 13857, or the appropriate standard.
The guard must be strong enough and designed to protect personnel and contain hazards within the guarded area that can
be ejected, dropped, or emitted by the machine. Mount them securely so that their physical position cannot shift, using
reliable fasteners that require a tool to remove. Mounting slots in the housing, if provided, are for initial adjustment only;
final mounting holes (round) must be used for permanent location. The switches, actuating systems, and actuators must
not be used as a mechanical or end-of-travel stop.
The normally closed safety contacts are of a "positive-opening" design. Positive-opening operation causes the contacts to
be forced open, without the use of springs, when the actuator is disengaged or moved from its home position. In addition,
the switch(es) must be mounted in a "positive mode", to move/disengage the actuating system and actuator from its
home position and open the normally closed contact, when the guard opens.
See Mechanical Installation, Electrical Installation, Switching Diagrams, and Specifications for additional information.
Design and install the safety switches and actuators so that they cannot be easily defeated. Measures to minimize defeat
(bypassing) of interlocking safety switches include:
• Minimizing motivation for defeating interlocking by providing training, supervision, and efficient means for machine
setup/adjustment, operation and maintenance
• Limiting accessibility to the interlocking device, such as mounting out of reach, mounting behind a physical
obstruction, mounting in a concealed position
• Preventing actuation by readily available objects or tools
• Preventing the switch or the actuator from being disassembled or repositioned that compromises the safety
function. (for example, welding, one-way screws, riveting)
• Control system monitoring of cyclic switch functioning and redundant means of interlocking
• Using hardware that requires a tool to remove that is not readily available.
WARNING: Interlocked Guards
The user must refer to the relevant regulations and comply with all necessary requirements. See ANSI
B11.19, or ISO 14119 and ISO 14120, or the appropriate standard. At a minimum, the interlocked
guard must prevent hazards when not fully closed and must also prevent access to the hazards through
any opening in the guard. The safety switches and actuators must be designed and installed so that
they cannot be easily defeated, and are not used as a mechanical or end-of-travel stop. At least one
switch must be mounted in a positive mode and open the normally closed contact when the guard
opens. Failure to follow these guidelines may result in serious bodily injury or death.
Safety Limit Switches
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