ES31x.1 User’s Guide
19
ETAS
Functional Description
5
Functional Description
This chapter contains information about the following topics:
• "Sensor Connections" on page 19
• "Data Transmission" on page 20
• "Tool Integration" on page 23
• "Firmware Update" on page 23
5.1
Sensor Connections
All sensor connections of ES31x feature identical designs. Each sensor connec-
tion consists of the function groups
signal processing
and
filter
as well as sensor
power supply.
5.1.1
Signal Processing and Filter
In every sensor connection, a capacitively compensated voltage divider limits the
level of the input signal after the overvoltage protection. An amplifier matches
the input signal to the following analog anti-aliasing filter according to the selec-
tion of the input voltage range.
An A/D converter digitizes the output signal of the analog filter. The separate A/
D converter that is integrated in every sensor connection ensures the synchro-
nous sampling of the measuring signals.
A digital filter then processes the digital signal. The digital filter can be config-
ured in the application program. At the output of the digital filter, the data is
written into a data buffer, where they are available for the query by the applica-
tion program.
Scaling of the measuring ranges
Depending on the channel, different measuring ranges are available which can
be configured on an individual basis.
Adjustability of the filter
To avid aliasing effects, a hardware filter can be activated. The hardware filter is
especially recommended for measuring periodic signals.
Averaging (moving average) smoothes undesirable signal jumps or noise compo-
nents.
The software filter enables an additional signal filtering. For this purpose, the
filter type and the cutoff frequency are selected.
5.1.2
Electrical Isolation
The sensor connections and the individually adjustable sensor supply voltages are
electrically isolated to each other, to the other channels, to the supply voltage
and to the CAN bus.