ETAS ES4440.2 - Relay or MOSFET; Duration of the Failure State; Simulating Loose Contacts; Number of Possible Active Failure States

ES4440.2 Compact Failure Simulation Module - User’s Guide22
Hardware Features ETAS
2.2.3 Relay or MOSFET
Using MOSFETs has the advantage of disappearing switching times – minimal
leakage currents are usually no problem for most types of failure. If, however,
they are, you can use relays to generate failures.
Please note, however, that failure modes which are switched via MOSFETs, can
only be realized individually (see Fig. 2-1 on page 20 and Fig. 2-2 on page 21).
Relay Specifications
The relays and the conductors of the ES4440.2 are designed to simulate failures
with ECUs – usually, the corresponding output stages are disabled only a few μs
after an failure has occurred.
Currents of 20 A (high-current channels) are possible in continuous operation –
in addition, the current paths are protected with fuses (exception: see row 4 in
Tab. 2-1).
2.2.4 Duration of the Failure State
The period of time for which an failure is active can be of interest for measuring
latencies of the diagnostic system. For example, the ES4440.2 can simulate a
specific failure for 20 ms, but the ECU software requires at least 30 ms to gener-
ate an failure memory entry.
The required duration of the failure state is set in the LABCAR-PINCONTROL user
interface. The selectable duration is between 20 ms and 60 s for relays and
between 1 ms and 60 s for MOSFETs – it can be set in intervals of 20 ms for relays
or 1 ms for MOSFETs.
2.2.5 Simulating Loose Contacts
Certain types of failure on high-current channels can not only be realized as fail-
ures with a defined duration but also as loose contacts. These failures are con-
trolled by a pulse-width modulation with a switching frequency of 3 Hz - 100 Hz
and a duty cycle of 1% - 99% (2 Hz with a duty cycle of 50%).
2.2.6 Number of Possible Active Failure States
With failures which are switched by relays, a maximum of ten failures can be
activated simultaneously (e.g. open loads on ten channels). For the shorts to the
battery voltages, it is also possible to simulate other failures at the same time –
these cannot, however, be selected freely. If you are using LABCAR-PINCONTROL
for failure simulation, failures which cannot be selected are excluded from the
selection in the user interface.
If, however, you address the ES4440.2 automatically by Ethernet or CAN, you
should ensure that the selected types of failure are also possible simultaneously
as otherwise an failure message will be issued. Take a look at Fig. 2-3 to see
which failures can be activated at the same time.