Technical Data - ABB REG650 Technical Manual

1MRK 502 034-UEN -
16.2.5
Technical Manual
IEC05000296 V2 EN
Figure 239: Simplified drawing of A/D converter for the IED.
The technique to split the analog input signal into two A/D converters with
different amplification makes it possible to supervise the incoming signals under
normal conditions where the signals from the two converters should be identical.
An alarm is given if the signals are out of the boundaries. Another benefit is that it
improves the dynamic performance of the A/D conversion.
The self-supervision of the A/D conversion is controlled by the ADx_Controller
function. One of the tasks for the controller is to perform a validation of the input
signals. This is done in a validation filter which has mainly two objects: First is the
validation part that checks that the A/D conversion seems to work as expected.
Secondly, the filter chooses which of the two signals that shall be sent to the CPU,
that is the signal that has the most suitable level, the ADx_LO or the 16 times
higherADx_HI.
When the signal is within measurable limits on both channels, a direct comparison
of the two channels can be performed. If the validation fails, the CPU will be
informed and an alarm will be given.
The ADx_Controller also supervise other parts of the A/D converter.

Technical data

Table 404: Self supervision with internal event list
Data
Recording manner
List size
Basic IED functions
ADx
Adx_Low
x
1
u
1
x
2
Adx_High
x
1
u
1
x
2
Value
Continuous, event controlled
40 events, first in-first out
Section 16
Adx
Controller
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