Digital modules
3.10 Digital input module SM 321; DI 16 x 24 VDC; with hardware and diagnostic interrupts
S7-300 Automation System Module data
Manual, 08/2006, A5E00105505-04
3-31
Reaction to power failure
Failure of the SM 321; DI 16 x DC 24 power supply is always indicated by the module's SF
LED. This information is also available on the module.
The input value is initially held for the duration of 20 ms to 40 ms before the zero signal is
transferred to the CPU. Supply voltage dips <20 ms do not influence the process value (see
the table above.)
Diagnostics interrupts are triggered according to parameter settings (see
Interrupts of
SM 321; DI 16 x DC 24 V
).
Power supply failure with redundant external encoder supply
Note
When an external redundant power source is connected in parallel to the sensor supply (Vs)
and the L+ power supply fails, the module does not report failure of the encoder supply, but
rather failure of the internal and/or external auxiliary voltage, and/or a blown fuse.
Short-circuit at the encoder supply Vs
The relevant Vs LED goes dark if a short-circuit is detected at the encoder supply Vs,
irrespective of parameter settings.
3.10.5 Interrupts of SM 321; DI 16 x DC 24 V
Introduction
This chapter describes the interrupt reaction of SM 321; DI 16 x DC 24 V. We distinguish the
following interrupts:
● Diagnostic interrupt
● Hardware interrupt
For detailed information on the OBs and SFCs mentioned below, refer to the STEP 7 Online
Help.
Enabling interrupts
There is no default interrupt setting, i.e. interrupts are disabled if parameters are not set
accordingly. You can enable interrupts in STEP 7 (see the chapter
Parameters of SM 321;
DI 16 x DC 24 V
).
(6ES7321-7BH01-0AB0)