Special Interfacing Considerations - Tapeswitch GS-120 Technical Manual

Release 7/2009 Ver. 1.0
CAUTION
Arc Suppressors must not be connected
across safety relay contacts.
Machine
Control
Voltage
Safety
Output
1
Safety
Fuse
Figure 40 - Interfacing a Machine with 1 MPCE
Machine
Control
Voltage
Safety
Output
1
Safety
Fuse
Safety
Output
2
Safety
Fuse
Figure 41 - Interfacing a Machine with Dual
Identical MPCEs
SAFETY FUSES: It is good practice to protect the
safety relays against welding due to a current surge.
This can be done by current limiting designs in the
machine's controls, or by simple fusing as shown in
Figure 40 and 41. The current through the safety
output contacts should be limited to a level below that
TAPESWITCH CORPORATION
100 Schmitt Boulevard
Farmingdale, New York 11735
Arc
Suppres s or
Safety
Output
2
MPCE
1
Arc
Suppres s or
MPCE
1
Arc
Suppres s or
MPCE
2
Technical Manual: GS-120 Light Curtain Systems
which could cause the contact to weld. Fuses with a
current rating less than that of the output contacts
should be used.
On the BSRSA Interface Unit, these safety (output
protection) fuses are part of the unit. All of the other
interface units do not provide safety fuses (output
protection) and these fuses should be supplied
externally by the user.

4.1.2 SPECIAL INTERFACING CONSIDERATIONS

4.1.2.1 PNP Version Manual Reset
It may be possible to connect the GS-120 directly to the
Machinery Primary Control Elements (MPCE). The GS-
120 in this configuration provides the Start/Restart
function necessary to avoid unintended initiation of the
machine.
4.1.2.2 PNP Version Auto Reset
The GS-120 can be used in Auto Restart mode. If this
mode is selected, the Manual Restart function must be
provided elsewhere in the machine safety control
system (for example, in the SRUB interface unit).
4.1.2.3 SSR Version
The interfacing of a GS-120 light curtain with SSR
outputs requires a controller that is compatible with
these devices. Care should be taken to ensure that the
inputs of this unit can accept the volt-free outputs of the
light curtain, and that the outputs of the light curtain are
wired with one channel "pull up" and one channel "pull
down" so as to maintain the failure mode integrity.
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Fax: 631-630-0454
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