Siemens SIMATIC ET 200SP HA Equipment Manual page 30

Parameters/address space
5.2 Description of parameters
Diagnostics: Wire break
Enables the wire break test. The wire break test must be activated for wire break detection to take
place.
Input delay (ms)
To suppress injected interference, you can set an input delay for a channel or channel pair.
Interference pulses whose pulse time is less than the set input delay (in ms) are suppressed.
Suppressed interference pulses are not visible in the process image input (PII).
A long input delay suppresses longer interference pulses but results in a longer response time.
Dependencies:
• The values available for the input delay depend on the "Time for short-circuit test (ms)" of the
configured sensor supply.
• The value "Time for short-circuit test (ms)" must be more than twice as large as the
configured "Input delay (ms)".
• The "Input delay (ms)" of a channel must be less than the configured "Discrepancy time (ms)"
if the "1oo2 evaluation, equivalent" or "1oo2 evaluation, non-equivalent" option is selected
for the "Sensor evaluation" parameter in the respective channel pair.
In 1oo2 evaluation, the input delay of the lower-order channel (channel n) also applies
automatically to the higher-order channel (channel n+8).
Note
Due to physical properties, crosstalk of signals can occur on longer unshielded signal wires (see
section "Electromagnetic compatibility" in system manual Distributed I/O System ET 200SP HA
(https://support.industry.siemens.com/cs/ww/en/view/109761547)).
Adjust the input delay or use shielded signal wires to avoid possible passivation of fail-safe digital
inputs and shutdown of the sensor supply.
Pulse stretching (s)
Pulse stretching is a function for extending a digital input signal. A pulse on a digital input is
extended to at least the configured length. If the input pulse is already longer than the
configured length, the pulse is not changed.
How the fail-safe input module works:
The fail-safe input module only stretches pulses with the value "0". That is because the safety
concept is based on existence of a safe state for all process variables. For digital F-I/O, this is the
value "0". This applies to sensors and actuators. Impulses with the value "1" are ignored.
With "1oo2" evaluation, the first pulse with value "0" triggers pulse stretching.
After pulse stretching starts, further impulses with the value "0" are ignored.
Principle:
The following figure shows pulse stretching of the fail-safe input module.
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Equipment Manual, 08/2021, A5E45647528-AD
F-DI 16x24VDC HA