Ensuring a wire break check is carried out
To ensure that a wire break check is carried out, you require an external sensor circuit using
a resistor of 10 to 18 kΩ. The resistor should be connected parallel to the contact and should
be arranged as closely as possible to the sensor.
This additional resistor is not required in the following cases:
● If 2-wire BEROs are used
● If you do no configure the "Wire break" diagnostics
Setting the input delay for channel groups
You can only set the input delay for each group of channels. In other words, the setting for
channel 0 applies to inputs 0 to 7 and the setting for channel 8 applies to inputs 8 to 15.
Note
The parameters that are entered for the remaining channels (1 to 7 and 9 to 15) must be equal
to the value 0 or 8, otherwise those channels will be reported as being incorrectly configured.
Any hardware interrupts that have occurred in the meantime will be reported after
acknowledgement.
Optimum signal propagation delays
You can achieve the fastest signal propagation delay with the following settings:
● Both channel groups are configured with an input delay of 50 µs
● All the diagnoses (load voltage error, wire break) are deactivated
● Diagnostic interrupt is not enabled
See also
Digital modules
4.8 Digital input module SM 421; DI 16 x DC 24 V (6ES7421-7BH01-0AB0)
S7-400 Automation System Module Data
106
Reference Manual, Ausgabe 11/2016, A5E00850736-08