Velodyne Acoustics HDL-64E S2 - Manual (Page 13)

Control Spin Rate
Change Spin Rate in Flash Memory
The sensor can spin at rates ranging from 300 RPM (5 Hz) to 1200 RPM (20 Hz). The default is 600 RPM (10 Hz). Changing the spin rate
does not change the data rate – the unit sends out the same number of packets (at a rate of ~1.3 million data points per second) regardless
of its spin rate. The horizontal image resolution increases or decreases depending on rotation speed.
See the Angular Resolution section found in Appendix I for the angular resolution values for various spin rates.
To control the sensor’s spin rate, issue a serial command of the case sensitive format #HDLRPMnnnn$ where nnnn is an integer between
0300 and 1200. The sensor immediately adopts the new spin rate. You don’t need to power cycle the unit, and the new RPM is retained
with future power cycles.
Change Spin Rate in RAM Only
If repeated and rapid updates to the RPM are needed, such as for synchronizing multiple sensors controlled by a closed loop application,
you can adjust the sensors’ spin rates without storing the new RPM in flash memory (this preserves flash memory over time).
To control the sensor’s spin rate in RAM only, issue a serial command of the case sensitive format #HDLRPNnnnn$ where nnnn is an
integer between 0300 and 1200. The sensor immediately adopts the new spin rate. You shouldn’t power cycle the sensor as the new RPM
is lost with future power cycles, which returns to the last known RPM.
Limit Horizontal FOV Data Collected
The sensor defaults to a 360° surrounding view of its environment. It may be desirable to reduce this horizontal Field of View (HFOV) and,
hence, the data created.
To limit the horizontal FOV, issue a serial command of the case sensitive format #HDLFOVsssnnn$ where:
• sss = starting angle in degrees; sss is an integer between 000 and 360
• nnn = ending angle in degrees; nnn is an integer between 000 and 360
The HDL unit immediately adopts the new HFOV angles without power cycling and will retain the new HFOV settings upon power cycle.
Regardless of the FOV setting, the lasers will always fire at the full 360° HFOV. Limiting the HFOV only limits data transmission to the HFOV
of interest.
The following diagram shows the HFOV from the top view of the sensor.
Examples
Case 1: FOV 0° to 360°
FOV command: #HDLFOV000360$
Case 2: FOV 0° to 90°
FOV command: #HDLFOV000090$
Case 3: FOV -90° to 90°
FOV command: #HDLFOV270090$
Top view of Sensor
[ 10 ]
HDL-64E S2 and S2.1 User’s Manual
usaGe