а вот инфа
The AD-converter-test consists of the low-idle test pulse process and the ADC-testvoltage-check:
For this AD-converter-test, the low-idle test pulse process is used which contains a cyclic value and update check. Here, the voltage at the
AD-channel is switched to mass in cyclical intervals of 320ms. During this action, it is checked, whether the AD-converter is capable of converting
this voltage. In the present case, the internal controller hardware at the ADC-input is used for switching operation.
The ADC-testvoltage-check reads a fixed testvoltage and checks the converted value for valid values. By this check particularly reference faults
and amplification faults of the ADC are detected.
The AD-converter-test with low-idle test pulse process serves to detect faults through which no update of the converted values is performed.
These faults cannot be detected by means of a plausibility check of two AD-channels, as they are plausible towards each other. Furthermore, it
is detected, whether the AD-converter is capable of converting voltage values below a defined threshold. Thus it is checked, if a drivers demand
'low-idle' can be converted
для чего это делается