Mode And Communication Selection - Honeywell HG1120 Installation And Interface Manual

HG1120 Installation and Interface Manual

Mode and Communication Selection

The HG1120 supports the message protocols, data rates, and bandwidths, described in Table 2.
The HG1120 can be configured by setting discrete inputs DIO1 through DIO4. These pins are only
read upon reset or power up. State of the pins is shown in word 9 of the multiplexed status word.
The first frame of serial output data after power-application will contain a fixed pattern of 0x55s in
place of sensor data. Subsequent frames of serial output data will contain compensated sensor data.
The control bandwidth in Table 2 describes the nominal - 90° phase point. The -3dB frequency
is nominally 2x the -90° phase frequency. The bandwidth is exclusive of transmission delay.
Control data consists of the angular rates, linear acceleration, magnetic, and IMU status words in
message set {0x04, 0x05} and set {0x0C, 0x0D}. The angular and linear data is filtered and sampled
at 1800 Hz. The 1800 Hz filtered angular and linear data is decimated for 600 Hz control data.
The 300/100 Hz navigation data output consists of incremental (or "delta") angles and velocities
as shown in message IDs 0x05 and 0x0D. The navigation data is unfiltered 1800 Hz sensor data
which is summed to the navigation data rate (300 Hz or 100 Hz). Accurate attitude and position
calculations require that all messages be received and used.
Gyro and accelerometer residuals are calculated and carried forward to the next message for both
navigation and control data. The serial output FIFO is loaded with the LS byte first and LS 16-bit
word first. The sensor data (gyro, accelerometer, magnetometer, and temperature) are all signed 2's
complement integers.
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