Thommen AD20 - 2.4.2 Built-in-Test

REVUE THOMMEN AG
CH-4437 Waldenburg
AD20 Standby Altimeter
Page 32 of 72
07-Sep-2009 Document No: AD-INSOP-800 Revision: 1.6
2.4.2 Built-in-Test
2.4.2.1 BIT Overview
BIT When? Action Duration
Startup BIT primary, emergency or
battery power switched on
after power off condition
(reset released)
- display all LCD segments
- find pointer null
- test internal circuits
- test lightings white/amber
- display battery charge
- display Config ID
- display selected A/C type
As long as pointer
resets
< 10 s totally
Initiated BIT TEST (EXTERNAL)
activated
- same as Startup BIT - same as Startup BIT
Continuous BIT Background operation,
once within 10 s
- test internal circuits and
operating cond.
--
Table 2-10 Built-in Test Overview
2.4.2.2 Start Up BIT
The flight instrument has a start-up built in Test (BIT) function, which is activated upon the application
of primary power to the instrument.
2.4.2.3 Initiated BIT
The flight instrument can be initiated for built in Test (BIT) function, by pushing the “TEST” button.
Then the Startup LCD including Startup BIT sequence is repeated.
2.4.2.4 Continuous BIT
The flight instrument has internally the continuous BIT sequence function, which is all the time active
during normal operation of the instrument.