Chapter 3 SPAN OperationOEM7 SPAN Installation and Operation User Manual v4 97l For the PwrPak7, the wheel sensor is connected to the HD26 COM PORTS connectorl For the IMU Enclosure (IMU-HG1900, IMU-ISA-100C, IMU-ENC-LN200 or IMU-μIMU-IC), thewheel sensor is connected to the Wheel Sensor port using the optional Wheel Sensor Cable(60723137) or a custom cable. See IMU Enclosure Wheel Sensor Cable on page 160 forinformation about the Wheel Sensor Cable and the Wheel Sensor port pinout.l For the IMU-FSAS and IMU-CPT, the wheel sensor is integrated via the IMU and wheel velo-city commands are not required.l For the IMU-IGM-A1 and IMU-IGM-S1, the wheel sensor is connected to the AUX port on theenclosure.For information about connecting a wheel sensor, refer to Wheel Sensor Installation on page 66.3.7.1 Wheel Sensor Data Collected on the PwrPak7The PwrPak7 accepts input from a wheel sensor on the HD26 COM PORTS connector. SeePwrPak7 Connectors in the PwrPak7 Installation and Operation User Manual for informationabout the COM PORTS connector.Measurement Timing and FrequencyTypical wheel sensor hardware generates wheel ticks constantly as the wheel rotates. ThePwrPak7 interface is configured to accumulate wheel sensor tick counts at a rate of 1 Hz.Wheel Sensor Update LogicWheel sensor data is available through the TIMEDWHEELDATA log. The TIMEDWHEELDATAlog can be used for applying wheel sensor updates in post-processing.The SPAN filter uses sequential TIMEDWHEELDATA logs to compute a distance traveled betweenupdate intervals (1 Hz). This information is used to constrain free inertial drift during times ofpoor GNSS visibility. The filter also contains a state for modeling the circumference of the wheelas it may change due to hardware changes or environmental conditions.The modeled wheel circumference is available in the WHEELSIZE log. Information about howthe wheel sensor updates are being used is available in the INSUPDATESTATUS log.Set up a Wheel Sensor1. Send the following command to setup the wheel sensor.SETWHEELPARAMETERS 1.0The parameters entered in the SETWHEELPARAMETERS command depend on thewheel sensor being used. For more information about this command see theSETWHEELPARAMETERS command in the OEM7 Commands and Logs Refer-ence Manual.2. Send the following commands to log the wheel sensor data.LOG WHEELSIZEB ONCHANGEDLOG TIMEDWHEELDATAB ONNEW
