2
7
1
6
9
5
2
0
1
7
-1
2
24
SLCT* and SLCT*/35 safety light curtains
Installation
4.4.2
Signal Inputs on the Transmitter Unit
Test input
Connect the test input to 24 VDC via an NC contact. The test function is triggered
by opening the contact.
The test input is used to start a complete test of the safety light curtain. During this
process, the OSSDs are switched off and all system components are checked.
Error messages from the transmitter unit are acknowledged by initiating a test.
The time constraints of the test signal must be maintained for a test to be
successful (
see Figure 4.5 on page 24). On an SLCT30-600 safety light
curtain, for example, the time between the test requirement and the response to
the OSSDs is a minimum of 6 ms and a maximum of 18 ms. A test input actuation
time of fewer than 0.02 s or more than 2.4 s switches the transmitter unit to a fault
state.
Figure 4.5
Graphs of the OSSD switching states when initiating a test or reset
A/B mode input
If the input is open or connected to 0 V, the safety light curtain operates in mode A.
The inputs must be connected to the supply voltage 24 VDC to switch to mode B.
Note!
During operation without a startup/restart interlock, the test time must be limited to
150 ms.
Note!
A complete test is also carried out when the operating voltage is switched on. This
also applies to the receiver unit, which does not have a test input.
Note!
In case of a fault, a fault reset can be triggered by activating the input between
1.2 s and 2.4 s.
Min. 0,4 x response time
Max. 0,8 x response time
Min. 0,4 x response time
Max. 1,2 x response time
min. 20 ms / max. 2,4 s
high
low
ON
OFF
OSSDs
Test
