Analog value representation
4.4 Effect on analog value representation
2AI TC HF analog electronic module (6ES7134-4NB01-0AB0)
Manual, 04/2007, A5E01076892-01
25
4.4
Effect on analog value representation
4.4.1
Effect of the supply voltage and the operating state on analog input values
The input values of the analog modules are dependent on the supply voltage for
electronics/encoders and on the operating state of the PLC (CPU of the DP master). This is
illustrated by the table below.
Table 4-14 Relationship between the analog input values for the operating state of the PLC (CPU of
the DP master) and the supply voltage L+
Operating state of the PLC
(CPU of the DP master)
Supply voltage L+ on
ET 200S (power
module)
Input value of the electronic module with
analog inputs (evaluation possible on the
CPU of the DP master)
Process values
L+ present
7FFF
H
until first conversion after startup, or
after assignment of parameters for the
module is completed.
POWER ON RUN
L+ missing
7FFF
H
L+ present
Process value
POWER ON STOP
L+ missing
7FFF
H
L+ present
-
POWER OFF -
L+ missing
-
4.4.2
Effect of the value range on the 2AI TC HF analog input
The way electronic modules respond to analog inputs depends on where the input values fall
within the value range. This is illustrated by the table below.
Table 4-15 Response of the analog modules, depending on where the analog input value falls within the range of values
Measured value within ...
Input value in SIMATIC S7 format
Input value in SIMATIC S5 format
Nominal range
Measured value
Measured value
Over-/underrange
Measured value
Measured value
Overflow
7FFF
H
End of the overshoot range +1 plus
overflow bit
Underflow
8000
H
End of the underrange -1 plus overflow
bit
Prior to parameter assignment, or
incorrect parameter assignment
7FFF
H
7FFF
H
