May 22, 2023
EZ-SCREEN SLS Safety Light Curtain Instruction Manual
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WARNING:
OSSD Interfacing
Failure to properly interface the OSSD Outputs to the guarded machine could result in serious in-
jury or death.
To ensure proper operation, the Banner device output parameters and machine input parameters
must be considered when interfacing the Banner device OSSD outputs to machine inputs. Design
machine control circuitry so that all of the following are true:
The maximum load resistance value is not exceeded.
The maximum specified OSSD OFF-state voltage does not result in an ON condition.
Final switching devices (FSDs) take many forms. The most common are forced-guided devices, mechanically linked relays,
or interface modules. The mechanical linkage between the contacts allows the device to be monitored by the external device
monitoring (EDM) circuit for certain failures.
Depending on the application, the use of FSDs can facilitate controlling voltage and current that differs from the OSSD out-
puts of the
EZ-SCREEN SLS. FSDs can also be used to control an additional number of hazards by creating multiple safety
stop circuits.
A protective stop (safety stop) allows for an orderly cessation of motion for safeguarding purposes, which results in a stop of
motion and removal of power from the MPCEs (assuming this does not create additional hazards).
A protective stop circuit typically comprises a minimum of two normally open contacts from forced-guided, mechanically
linked relays, which are monitored through External Device Monitoring (EDM) to detect certain failures to prevent the loss of
the safety function. Such a circuit can be described as a "safe switching point". Typically, protective stop circuits are either
single-channel, which is a series connection of at least two normally open contacts; or dual-channel, which is a separate con-
nection of two normally open contacts. In either method, the safety function relies on the use of redundant contacts to control
a single hazard. If one contact fails On, the second contact arrests the hazards and prevents the next cycle from occurring.
See
The interfacing of the protective stop circuits must be accomplished so that the safety function cannot be suspended, overrid-
den, or defeated unless accomplished in a manner of the same or greater degree of safety as the machine’s safety-related
control system that includes the
EZ-SCREEN SLS
.
The normally open safety outputs from an interface module provide a series connection of redundant contacts that form pro-
tective stop circuits for use in either single-channel or dual-channel control. See
.
Dual-channel control provides the ability to electrically extend the safe switching point beyond the FSD contacts.
With proper monitoring, this method of interfacing is capable of detecting certain failures in the control wiring between the
safety stop circuit and the MPCEs. These failures include a short-circuit of one channel to a secondary source of energy or
voltage, or a loss of the switching ability of one of the FSD outputs. Such failures may lead to a loss of redundancy, or to a
complete loss of safety, if not detected and corrected.
The possibility of a failure to the wiring increases as the physical distance between the FSD safety stop circuits and the
MPCEs increases, as the length or the routing of the interconnecting wires increases, or if the FSD safety stop circuits and
the MPCEs are located in different enclosures. For this reason, dual-channel control with EDM monitoring should be used in
any installation where the FSDs are located remotely from the MPCEs.
Single-channel control uses a series connection of FSD contacts to form a safe switching point.
After this point in the machine’s safety-related control system, failures can occur that would result in a loss of the safety func-
tion (such as a short-circuit to a secondary source of energy or voltage). For this reason, single-channel control interfacing
should be used only in installations where FSD safety stop circuits and the MPCEs are mounted within the same control pan-
el, adjacent to each other, and are directly connected to each other; or where the possibility of such a failure can be exclud-
ed. If this cannot be achieved, then dual-channel control should be used.
Final Switching Devices (FSD) Interfacing Connections
5.9.2
Protective Stop (Safety Stop) Circuits
Dual-Channel Control
Single-Channel Control
© Banner Engineering Corp.
Содержание EZ-SCREEN SLS
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