How The Input Values Depend On The Operating Mode Of The Cpu - Siemens Simatic M7-400 Reference Manual

4.9.2 Behavior of the SM 421; DI 16
Effect of Operating Mode and Supply Voltage on the Input Values
The input values of the SM 421; DI 16
the CPU and on the supply voltage of the module.
Table 4-11 How the Input Values Depend on the Operating Mode of the CPU and on the
CPU Operating Mode
POWER ON
POWER
OFF OFF
* Depends on the parameter assignment (see Table 4–12 )
Behavior upon Failure of the Supply Voltage
Failure of the supply voltage of the SM 421; DI 16
the EXTF LED on the module. Furthermore, this information is made available on
the module (entry in diagnosis).
Triggering of the diagnostic interrupt depends on the parameter assignment (see
Section 4.9.1).
Short-Circuit of Sensor Supply Vs
Irrespective of the parameter assignment, the corresponding Vs LED goes out if a
short-circuit of the encoder supply Vs occurs.
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Supply Voltage L+ of the SM 421; DI 16
Power Supply L+
to Digital Module
RUN L+ exists
L+ missing
STOP L+ exists
L+ missing
– L+ exists
L+ missing
24 VDC
24 DC depend on the operating mode of
24 VDC
Input Value of Digital Module
Process value
0 signal *
Process value
0 signal*
–
–
24 DC is always indicated by
Digital Modules
4-29