DMU380ZA Series
User’s Manual
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Doc# 7430-3810 Rev.02
Page 17
rate over-ranges result in unrecoverable errors in roll and pitch outputs. An unrecoverable
error is one where the EKF can not stabilize the resulting roll and pitch reading. If the
over-ranges are expected to be of short duration (<1 sec) and a modest percentage over
the maximum operating range, it is recommended that the restart on over range setting
be turned off. Handling of an inertial rate sensor over-range is controlled using the
restartOnOverRange switch. If this switch is off, the system will flag the overRange status
flag and continue to operate through it. If this switch is on, the system will flag a
masterFail error during an over-range condition and continue to operate with this flag until
a quasi-static condition is met to allow for an algorithm restart. The quasi-static condition
required is that the absolute value of each low-passed rate sensor fall below 3 deg/sec to
begin initialization. The system will then attempt a normal algorithm start.
Dynamic
Motion
ON
The default setting is ON for the VG380ZA. Turning off the dynamic motion setting results
in a higher gain state that uses the accelerometer feedback heavily. During periods of
time when there is known low dynamic acceleration, this switch can be turned off to allow
the attitude estimate to quickly stabilize.
Turn Switch
threshold
10.0
deg/sec
With respect to centripetal or false gravity forces from turning dynamics (or coordinated
turn), the VG380ZA monitors the yaw-rate. If the yaw rate exceeds a given Turnswitch
threshold, the feedback gains from the accelerometer signals for attitude correction are
reduced because they are likely corrupted.
BIT
See 4.3.2
4.3.2
VG380ZA Built-In Test
As with the IMU380ZA, the VG380ZA Built-In Test capability allows users of the
VG380ZA to monitor health, diagnostic, and system status information of the unit in real-
time. The Built-In Test information consists of a BIT word (2 bytes) transmitted in every
measurement packet.
In addition, there is a diagnostic packet ‘T0’ that can be requested
via the Get Packet ‘GP’ command which contains a complete set of status for each
hardware and software subsystem in the VG380ZA. See Sections 6-8 for details on the
‘T0’ packet.
The BIT word contained within each measurement packet is detailed below. The LSB
(Least Significant Bit) is the Error byte, and the MSB (Most Significant Bit) is a Status
byte with programmable alerts. Internal health and status are monitored and
communicated in both hardware and software. The ultimate indication of a fatal problem
is the masterFail flag.
The masterStatus flag is a configurable indication that can be modified by the user. This
flag is asserted as a result of any asserted alert signals which have been enabled. See
Advanced BIT (Section 9) for details on configuring the masterStatus flags. Table 9
shows the BIT definition and default settings for BIT programmable alerts in the
VG380ZA.
Table 9 VG380ZA Default BIT Status Definition
BITstatus Field
Bits
Meaning
Category
masterFail
0
0 = normal, 1 = fatal error has occurred
BIT
HardwareError
1
0 = normal, 1= internal hardware error
BIT
comError
2
0 = normal, 1 = communication error
BIT
softwareError
3
0 = normal, 1 = internal software error
BIT
Reserved
4:7
N/A
masterStatus
8
0 = nominal, 1 = one or more status alerts
Status
hardwareStatus
9
Disabled
Status
