Behavior Of The Analog Inputs And Outputs During Operation And In The Event Of Faults - Siemens SIMATIC ET 200X Manual

7.21.6 Behavior of the analog inputs and outputs during operation and
in the event of faults
This chapter deals with the following topics:
S The dependency of the analog input and output values on the supply voltage of
the expansion module and the operating modes of the PLC
S The behavior of the analog expansion modules as a function of the position of
the analog values in the relevant value range
S The effect of errors on the analog inputs/outputs
Effect of the supply voltage and the operating mode
The input and output values of the analog modules are dependent on the supply
voltage for electronic components/sensors and on the operating mode of the PLC
(CPU of the DP master).
Table 7-59 How the analog input/output values depend on the operating mode of the PLC (CPU of the DP
master) and the supply voltage L +
Operating mode Supply vol-
of the PLC (CPU tage L + to
of the DP master)
Power RUN L + applied
on
L + not applied
Power STOP L + applied
on
L + not applied
Power – L + applied
off
L + not applied
ET 200X Distributed I/O Device
EWA 4NEB 780601602-06
Input value of the expansion
module with analog inputs
ET 200X and (evaluation possible in
the CPU of the DP master)
Process value
7FFF until the first conversion
H
after the module is switched on
or after the module is
parameterized
0 mA/0 V
0 mA/0 V
0 mA/0 V
–
–
Technical Specifications
Output value of the expan-
sion module with analog out-
puts
PLC value
Until the first conversion ...
S
after the module is
switched on, a signal of
0 mA or 0 V is output.
S
after the module is
parameterized, the
previous value is output.
0 mA/0 V
Substitute value/last value
(default: 0 mA/0 V)
0 mA/0 V
0 mA/0 V
0 mA/0 V
7-103