WARNING: Series Connection of Safety Interlock Switches
Monitoring multiple guards with a series connection of safety interlock switches may result in a failure be-
ing masked or not detected at all. When such a configuration is used, periodic checks must be performed
regularly to verify proper operation. All failures must be immediately corrected ( e.g. immediately replacing
a failed switch), or the loss of the safety stop signal or an inappropriate reset could lead to serious injury or
death.
As shown, a normally-closed safety contact (i.e., a safety contact
that is closed when the actuator is engaged) from each of two
safety switches per interlock guard must connect to a 2-channel
safety module or safety interface to achieve a control reliable inter-
face to the master stop control elements of a machine. Examples
of appropriate safety modules include 2-channel emergency stop
(E-stop) safety modules and gate monitor safety modules.
Two functions of the safety module or safety interface are to:
1. provide a means of monitoring the contacts of both safety
switches for contact failure, and to prevent the machine from
restarting if either switch fails; and
2. provide a reset routine after closing the guard and returning
the safety switch contacts to their closed position. This pre-
vents the controlled machinery from restarting by simply
closing the guard. This necessary reset function is required
by ANSI B11 and NFPA 79 machine safety standards.
Use only the positively driven, normally closed safety contact (be-
tween pins 1 and 2) from each switch for connection to the safety
module. A typical use is to communicate with a process controller.
Refer to the installation instructions provided with the safety mod-
ules for more information regarding the interface of the safety mod-
ule to the machine stop control elements.
Safety Switch
#1
Safety Switch
#2
Input Channel
#1
Input Channel
#2
2-channel Safety Module
(2-channel E-stop Module
2-channel Gate Monitor Module, etc.)
Single gate
or guard
1
2
1
2
Figure 2. Hinge Wiring to Safety Module
Connect two redundant safety switches per interlock guard to an
appropriate 2-channel input safety module.
Refer to the installation instructions provided with the safety mod-
ule for information regarding the interface of the safety module to
the machine stop control elements.
Periodic Checks
A designated person should perform the following safety switch checks at each shift change or machine setup.
A designated person is identified in writing by the employer as being appropriately trained to perform a specified checkout procedure.
1. Check the switch body for damaged or broken parts.
2. Confirm the safety switch is not being used as an end stop.
3. Verify it is not possible to reach any hazard point through an opened guard (or any opening) before hazardous machine motion has
completely stopped.
4. Verify the hinge swings freely throughout its total operating range.
5. Tighten any loosened mounting hardware.
6. Check for signs of deterioration or damage.
7. Check for signs of tampering or defeat to the switch or to the wiring interface to the machine.
Repairs
Do not attempt any repairs to the Module. It contains no field-replaceable components. Return it to the factory for warranty repair
or replacement by contacting Banner Factory Application Engineering. They will attempt to troubleshoot the system from your description
of the problem. If they conclude a component is defective, they will issue a return merchandise authorization (RMA) number for your
paperwork and give you the proper shipping address.
Pack the Module carefully. Damage that occurs in return shipping is not covered by warranty.
Hinge Wing Safety Interlock Switches
4 www.bannerengineering.com - tel: 763-544-3164 P/N 046735 Rev. C