Remedy; Restrictions; Special Features Of Logo! 12/24 Rc/Rco And Logo! 24/24O - Siemens Logo! Manual

LOGO! installation and wiring
Take the quiescent current of any 2-wire proximity switches
used into account. The level of the quiescent current of
some 2-wire proximity switches is high enough to trigger a
logical "1" signal at the LOGO! input. You should therefore
compare the quiescent current of the proximity switches
with the technical data of inputs Appendix A.

Remedy

To suppress this response, use Siemens components with
the following order number: Capacitor 3SB 1420–3D. As an
alternative, you can also 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

S
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 LOGO! 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.

Special features of LOGO! 12/24 RC/RCo and LOGO! 24/24o

S
High-speed inputs: I5 and I6
These versions are also equipped with high-speed counting
inputs (Up/down counters, Threshold triggers). The
restrictions mentioned earlier do not apply to these
high-speed inputs.
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LOGO! Manual
A5E00380835-01