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8 007 487/ 10-10-99 Technical Description • LGT © SICK AG • Safety Systems • Germany • All rights reserved
Operating mode
Action
Indicators
„Without restart inhibit“
Break the protective field again
LGTN lights up green
Switch the voltage on and off
LGTN lights up green
„With restart inhibit“
Press the control switch
LGTN lights up green
5.3.5 Test input
The test input is used to initiate a
test cycle
(Fig. 19)
. In doing so, the
LGT including the main relay and
response time are monitored to
ensure that they are functioning
correctly. If a safety-relevant error is
detected during the test, the
switching ouputs remain open. The
machine, therefore, cannot resume
operation. A break contact must be
connected to the test input.
5.3.6 Contactor monitor
The external contactor monitor
monitors the contacts of connected
contactors to ensure that they are
do not stick (weld). These must be
connected to the LGT as shown in
the connection diagram
(Fig. 20)
.
The contactor monitor monitors
the
static
rest position of the exter-
nal contactors. If a
dynamic
contac-
tor monitor is specified, the moni-
tor must be integrated into the
higher-order controller.
3
4
+24V
1.2 k
Test contact
U
high
> 15V
U
low
< 5V
Contact closed:
Contact open:
no test
test
5
6
+24V
U
high
> 15V
U
low
< 5V
1.2 k
K1 K2
Contactor
Fig. 19. Test input circuit
Fig. 20. Contactor monitor circuit
Note
Safety can only be guaranteed if the
test input is used (installed in the
machine controller).
Note
If the protective field is broken very
briefly, a lockout together with the
error message 14 may occur in the
case of heavily rebounding contacts
(Table, below). The "Action" col-
umn gives the required measures.
If the contact monitoring is pro-
vided by externally connected de-
vices, terminals 5 and 6 must be
bridged.
