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6.8 Self diagnostics: Self Zero check and Span check
The unit can check zero output and span repeatedly and do the self
diagnostics. The interval for zero and span check can be set with parameters 8
and 9 (see Table 2. Parameter Change Table).
Parameter 8 sets the time period for the reference check. The period can be
from 0 to 99 hours (value 0 means: No reference check).
Parameter 8 :
Reference check Interval (hours) -> from 0 to 99 hour
Parameter 9 sets the alarm time if the reference check indicates an internal
error in the unit. The alarm time can be from 0 to 8 minutes (parameter 9 is set
to a value of from 0 to 8). If parameter 9 is set to value 0 then no alarm signal
will be given even if there is an error. If parameter 9 is set to value 9 then an
alarm is given continuously until the operator resets it.
If there is some internal error in the unit the reference check gives an alarm.
The alarm is given by setting mA output signal to 2 mA the period of time
depending on parameter 9 (0 - 8 minutes, or continuously until reset). The unit
compares the zero and the span values with the expected reference values
and gives an alarm if there is more than 2 % deviation compared to the full
scale. During self zero check and span check the relays are set to the service
mode. (Chapter 6.2)
Parameter 9:
Alarm time if reference check gives an alarm -> from 0 to 8 minutes or
continuously.
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