Accu-Chek Aviva Owner's Booklet page 22

9. Press to set the control level in the meter.
Chapter 2: Control Testing
10. The control result and "OK" alternate on the
display if the result is in range. The range is
printed on the test strip container label. The
control result and "Err" alternate on the display if
the result is out of range. Remove and discard the
used test strip.
20
in range
example
out of range
example