Moog Crossbow GNAV540 - Manual (Page 98)

Page 98
GNAV540 Use nual
7430‐0808‐01 Rev. B
r Ma
Chapter 11. Built In Test (BIT)
The Built‐In Test capability allows users to monitor health, diagnostic, and system status information of the unit in
real‐tim
ion e. Built‐In Test informat is transmitted in each measurement packet.
NOTE: A diagnostic test packet (T2) can be requested via GP. To contains a complete set of status for each hardware
and software subsystem. For more information, refer to Test 2 (Detailed BIT and Status) Packet on page 72
and Get Packet Request on page 68.
BIT Status Fields
Error by A BIT word consists of two bytes: te and Status byte.
The first byte (bits 0–7) is the Error byte: signaled results from internal checks. Four intermediate signals determine
when to assert masterFail and the hardware BIT signal. These signals are controlled by three categories of systems
checks: hardware (hardwareError), communication (comError) and software (softwareError). Instantaneous soft
the si nals
e has occur
failures from any category triggers g : a flag is raised. masterFail is not triggered until persistency
conditions are met or a hard failur red.
The second byte (bits 8–15) is the Status byte: signaled status alerts. Four intermediate signals determine when to
assert the masterStatus flag: hardwareStatus, sensorStatus, comStatus, and softwareStatus. masterStatus is the
logical OR of these intermediate signals. Each intermediate signal has a separate field with an indication flag. Each
indication flag can be enabled or disabled by the user. Any enabled indication flag will trigger the associated
tus flag. intermediate signal and masterSta
he BIT fields are summarized in T
s
Table 77 below. Table 78 provides additional information about the programmable
tatus field.
Table 77 Default BIT Status Values
BITstatus Field Bits Value Configurable
Error Byte fields (BIT) N
masterFail 0 0: normal
1: fatal error
rFail flag is thrown when either a hard failure (fatal
or a soft failure (persistent problem) occurs. The maste
condition)
N
hardwareError 1 0: normal
hardware error 1: internal
N
comError 2 0: normal
ication error 1: commun
N
softwareError 3 0: normal
1: internal software error or magAlignOutofBounds
NOTE: In AHRS and NAV modes, this bit provides information about
of magnetic alignment. If the unit has not been properly
lly calibrated, a softwareError will be indicated
the status
magnetica
N
GPSError 4 0: normal
1: GPS failure
N