Siemens Simatic M7-400 Reference Manual page 247

5.5 Behavior of the Analog Modules
Introduction
In this section, you will find information on:
• How the analog input and output values depend on the operating modes of the
CPU and the supply voltage of the analog module
• The behavior of the analog modules depending on where the analog values lie
within the value range
• The effect of errors on analog modules with diagnostics capability
• The effect of the operational limit of the analog module on the analog input and
output value, as illustrated by an example
5.5.1 Effect of Supply Voltage and Operating Mode
The input and output values of the analog modules depend on the operating mode
of the CPU and on the supply voltage of the module.
Table 5-38 Dependencies of the Analog Input/Output Values on the Operating Mode of the CPU and the
Supply Voltage L+
CPU Operating Supply Voltage L+ at
Mode Analog Module
POWER RUN L+ present
ON ON
L+ missing
POWER STOP L+ present
ON ON
L+ missing
POWER – L+ present
OFF OFF
L+ missing
* L+ only required with 2-wire transmitters
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Output Value of the Analog
Output Module
CPU values
Until the first conversion...
•
after power-up has been
completed, a signal of 0
mA or 0 V is output.
•
after parameter
assignment has been
completed, the previous
value is output.
0 mA/0 V
Substitute value/last value
(default values: 0 mA/0 V) (default values: 0 mA/0 V)
0 mA/0 V
0 mA/0 V
0 mA/0 V
Analog Modules
Input Value of the
Analog Input Module*
Measured value
7FFF until the first
H
conversion following
power-up or after
parameter assignment of
the module has been
completed
Measured value
7FFF until the first
H
conversion following
power-up or after power-up or after
parameter assignment of
the module has been
completed
–
–
5-31