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Release 7/2009 Ver. 1.0
3.3
ELECTRICAL INTERFACE,
OPERATION, and INSTALLATION
This section is divided into two parts. The first part
discusses the interface and operation of the GS-120
system when the basic set (emitter and receiver) is
interfaced directly to the machine control circuitry by
means of the redundant solid state outputs.
The second section discusses the interface when any
one of the various Tapeswitch control units is used.
The basic GS-120 system consists of an emitter and
receiver. The receiver unit provides two safety outputs.
These fail-safe outputs are solid-state PNP transistors
and are actively monitored and short-circuit protected.
The two outputs are independent of each other and
represent part of the redundancy of the overall light
curtain system. The outputs must always be in the
same state (i.e., both outputs either on or off). If one
output should fail in the "on" position, the other output
will remain in the "off" position until the failure is
corrected. In order to maintain redundancy both outputs
must be interfaced to independent switching devices in
the machine control circuit (i.e., safety relays,
emergency stop relay packages, fail-safe PLC'S, etc.).
Both outputs must be used. The solid state outputs
can be interfaced directly to the machine control circuit
provided this circuitry is compatible with the PNP-type
output.
A number of manufacturers produce units
containing circuits of this type. Care should be taken to
ensure that the inputs of these units can accept the PNP
outputs of the light curtain.
• The maximum current is 0.1 A.
• The output voltage, Ua, of each output is dependent
on the supply, Uv and the load and is given by the
following expression Ua > Uv - 2v.
• If the solid state outputs are used directly, the
supply voltage to the light curtain (emitter and
receiver) must be common to the supply voltage of
the device to which it will be interfaced.
• Both outputs must be used to maintain redundancy.
• Each output should be wired to independent switching
devices in the machine control circuit and SHOULD
NOT BE CONNECTED TOGETHER.
NOTE: The pair of solid state outputs are constantly
monitored and are designed to act as a single
component in a fail-safe condition (i.e., if one of the
outputs fails in the "on" position, the other output
will revert to the "off" position.
TAPESWITCH CORPORATION
100 Schmitt Boulevard
Farmingdale, New York 11735
Technical Manual: GS-120 Light Curtain Systems
This output will remain "off" until the integrity of the
other output is restored. This level of integrity must
be maintained throughout the machine control
circuit. It is the responsibility of the end user to
assure any fault within the safety circuit is detected
and that it puts the machine in a safe condition.
3.3.1
GENERAL
Both units must be supplied with 24 Vdc ± 20%. This
DC supply must be isolated by means of a safety
transformer which conforms to the requirements of
IEC61558-2-6. The emitter, receiver and interface unit
must use the same + 24V DC supply. The negative side
of the supply should be grounded and the cables should
be routed separately from power and motor drives.
The maximum cable length for each unit is 30 meters.
The power consumption is dependent on the protected
height of the system but is less than 12 VA.
The emitter and receiver should be powered by a
common DC supply and connected to the system
ground. If power is removed from the emitter only
the system may not automatically re-synchronize,
and may require power removal from the receiver as
well in order to establish optical communication and
synchronization. Power can be removed from the
receiver unit without any consequence to the
synchronization.
Power should be applied to both units at the
same time. If power is removed from the
emitter unit, power must also be removed
from the receiver unit.
3.3.2
EMITTER UNIT
3.3.2.1 General
The emitter unit has a five-pin male quick-disconnect
connector. Two pins for the DC supply, two for the test
input (see 3.3.2.2), and one for the ground. (protective
earth PE)
To connect to the emitter, a 5-pin female molded cable
assembly is necessary. This cable assembly is supplied
separately and is available in lengths of 15 feet (p/n
0972), 30 feet (p/n 0973), or 98 feet (p/n 0976). This
cable has an insulated jacket with color coded wires.
The cable has a fixed molded connector on one end and
flying leads at the other. The colors and corresponding
functions are shown in Figures 28 and 29.
27
IMPORTANT
Phone: 631-630-0442
Fax: 631-630-0454
www.tapeswitch.com
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