Crosstalk Between Channels - Siemens SIMATIC ET 200AL System Manual

What you should know about analog technology

2.13 Crosstalk between channels

2.13 Crosstalk between channels
Origin of the term
The term crosstalk/XT was originally used in the field of telecommunication to denote
unwanted coupling of voice signals between two cable conductors of different subscribers.
Definition
Crosstalk between signal channels denotes the interactive influence between two
independent channels as a result of leakage currents and capacitive or inductive coupling.
Crosstalk between the channels changes the signal by the value of the amplitude of the
crosstalk signal.
Causes
Technically, it is not feasible to totally isolate the module channels from environmental
conditions. This means that it is always possible for leakage currents or disturbance coupling
having an interactive effect.
Figure 2-18
The diagram shows the effects of crosstalk for the user with two channels (Ch
analog module. The crosstalk value is the factor by which the utility signal at a second
channel U
be calculated using the following equation:
34
Crosstalk between two channels
is affected by the signal at the first channel U
a2
/Ch
1
. The measuring error (U
e1
Analog value processing
Function Manual, 06/2014, A5E03461439-AC
) of an
2
) can
a1