Chapter 3 SPAN Operation
OEM7 SPAN Installation and Operation User Manual v14
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Figure 32: DMI to UIC Setup
DMI Data Collected on UIC
Typical DMI hardware generates wheel ticks constantly as the wheel rotates. When a DMI is connected to the
UIC, the wheel ticks are accumulated in the UIC. The accumulated wheel ticks, along with the raw data
received from the IMU, are sent the OEM7 receiver though the serial communication line.
DMI Update Logic
DMI data is available through the
RAWDMI
log. The
RAWDMI
log can be used for applying DMI updates in
post-processing.
The SPAN filter uses sequential
RAWDMI
logs to compute a distance traveled between update intervals (1 Hz).
This information is used to constrain free inertial drift during times of poor GNSS visibility. The filter also contains
a state for modeling the circumference of the wheel as it may change due to hardware changes or environmental
conditions.
Information about how the DMI updates are being used is available in the
INSUPDATESTATUS
log.
Connect the DMI to the UIC
To connect a DMI to the UIC:
1. Install the SPAN system components using the instruction in
When creating the UIC cabling, ensure the wheel sensor inputs on the UIC Receiver Communications Con-
nector (J102) are brought out to a separate connector or wire bundle.
2. Connect the DMI to the UIC wiring harness.
3. Connect an external power supply to the DMI.
The power required for the DMI depends on the DMI used. Refer to the DMI user documents for more inform-
ation.
