IDEC FL1E SmartRelay - Manual (Page 50)

IDEC SmartRelay installation and wiring
36 IDEC SmartRelay Manual 
Sensor connections
Connecting glow lamps and 2-wire proximity switches
(Bero) to FL1E-H12RCC/FL1E-B12RCC or FL1B-
M08C2R2 (AC)
The figure below shows how you connect a switch with a
glow lamp to IDEC SmartRelay. The current that flows
through the glow lamp allows IDEC SmartRelay to detect a
“1” signal even though the switch contact is not closed. If,
however, you use a switch the glow lamp of which is fitted
with a power supply, this response does not occur.
L1
N
N L1
C
X-capacitor 2.5 kV, 100 nF
Take into account the quiescent current of any 2-wire
proximity switches used. The level of the quiescent current
of some 2-wire proximity switches is high enough to trigger a
logical ”1” signal at the IDEC SmartRelay input. You should
therefore compare the quiescent current of the proximity
switches with the technical data of inputs in Appendix A.
Remedy
To suppress this response, use an X capacitor rated at

100 nF and 2.5 kV. In a destructive situation, this type of
capacitor safely disconnects. You must choose the voltage
level for which the capacitor is rated such that it is not
destroyed in the case of overvoltage!
At 230 V AC, the voltage between N and an input I(n) must
not be greater than 40 V to guarantee a ”0” signal. You can
connect approximately ten glow lamps to the capacitor.
Restrictions
Signal status transitions 0  1 / 1  0:
After a 0 to 1 or 1 to 0 transition, the signal must remain
constant at the input at least for the duration of one program
cycle, so that IDEC SmartRelay can detect the new signal
status.
The program execution time is determined by the size of the
circuit program. Appendix B contains a benchmark test
routine that you can use to determine the current scan cycle
time.