ETAS
Hardware Description
ES430.1 - User’s Guide
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The data is sent to the calibration software on the PC once acquired.
When measuring the internal resistance, the signal is filtered by a Bessel 2nd
order low-pass with a cutoff frequency of 5 Hz. The subsequent A/D converter
feeds a digital controller that controls sensor heating.
Depending on the sensor temperature, the R
i
measuring unit supplies a voltage
which, once filtered and digitized, is used as the actual value for controlling the
heating temperature of the sensor.
4.3.2
Heater Control
To operate the sensor at the nominal value of operating temperature, the cur
-
rent sensor internal resistance is permanently compared to its desired value
and the effective heating performance updated.
This control circuit can be operated independently of the digital part of the
ES430.1 and can therefore guarantee an operational sensor even when the
module is switched off.
4.3.3
Analog Output
The ES430.1 also has a port for analog output signals which can be used with
the sensor cables CBAL451.1 and CBAL4515.1.
The analog output of the ES430.1 is galvanically separated, protected against
shorts and overload (see section 8.8.4 on page 87).
4.4
Sensor Identification (TEDS)
The connected sensor must be identified which ensures that the operating
parameters of the ES430.1 correspond to the connected sensor and that errors
are impossible.
The sensor cables for the LSU4.9 contain an active component (TEDS) for
cable identification and therefore the connected Bosch Lambda Sensor
LSU4.9.
4.5
Sensor Cables
The sensor cables are equipped with a connector for the heating voltage of the
sensor as well as with a control line for the sensor heating. Sensor cables are
available both with and without an analog output socket.