5.6.2
Effect of supply voltage and operating mode
Overview
The IO values of analog modules are determined by the CPU operating state and the module's
supply voltage.
Table 5-38
Dependencies of the analog IO values on the CPU's operating State and on the L+ supply voltage
CPU operating state
Supply voltage L+ at the an‐
alog module
Output value of the
analog output module
Input value of the
analog input module*
POWER
ON
RUN
L+ present
CPU values
Measured value
Until the first conversion...
● after power-up has been
completed, a signal of 0 mA or
0 V is output.
● after programming is
successfully completed, it
outputs the previous value.
7FFF
H
, until the first conversion
after POWER ON is completed,
or when the module has been
programmed.
L+ missing
0 mA / 0 V
POWER
ON
STOP
L+ present
Substitution value / last value
(default: 0 mA / 0 V)
Measured value
7FFF
H
, until the first conversion
after POWER ON is completed,
or when the module has been
programmed.
L+ missing
0 mA / 0 V
POWER
OFF
-
L+ present
0 mA / 0 V
-
L+ missing
0 mA / 0 V
-
* L+ only required with 2-wire sensors
Behavior on failure of the supply voltage
Failure of the load power supply L+ of the diagnostics-capable analog module is indicated in
the case of configured 2-wire sensors by the EXTF LED on the module. This information is
also available on the module (in the diagnostic buffer data.)
Diagnostics interrupt triggering is based on parameter settings.
See also
General information about parameter assignment (Page 199)
Analog modules
5.6 Behavior of the analog modules
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08
193