Manual

SF11 Laser altimeter
Product manual
p: Confirm lost signal (0.0 ... 120.0 seconds)
Menu item <p> is used to set how long a lost signal is permitted before the out of range condition selected in menu item n: is
applied. When operating close to the measuring limit of of the SF11 or over water, signals may be lost intermittently. Rather than
jumping between the measured altitude and the out of range condition, this menu item can be set to hold the last valid altitude for
the entered time. If the lost signal persists for longer than this time then the out of range condition is applied. The lost signal time
can also be changed using the serial port or I2C command set.
q: Enable or disable the median filter menu (ON / OFF)
Menu item <q> is used to enable the median filter that can be used to reject transient changes in altitude caused by rough terrain,
bushes, fences, ditches or other small obstacles. This improves flight stability during automatic terrain following. The median filter
can also be enabled or disabled using the serial port or I2C command set.
Figure 12 :: Median Filter Response graph
r: Median filter size (3 … 32 results)
Menu item <r> sets the number of readings that are used by the median filter array. A bigger array will ignore unwanted objects for a
longer time.
The median filter size can also be changed using the serial port or I2C command set.
Item
HMI
Type
Serial
I2C
Lost signal timeout
menu item <p>
0 ... 120 sec
read
?FC<CR><LF>
.write(22) .read(a,b)
?FC 1<CR><LF>
timeout = (a*256+b)/100
write
#FC,1<CR><LF>
.write(23,a,b)
#FC,1 1<CR><LF>
a = (byte)(timeout*100 >> 8)
b = (byte)(timeout*100 & 0xff)
Item
HMI
Type
Serial
I2C
Median filter enable
menu item <q>
off ... on
read
?FM<CR><LF>
.write(24) .read(a)
?FM 1<CR><LF>
enable = a
write
#FM,1<CR><LF>
.write(25, a)
#FM,1 1<CR><LF>
a = 0 or 1
Item
HMI
Type
Serial
I2C
Median filter size
menu item <r>
3 ... 32
read
?FS<CR><LF>
.write(26) .read(a)
?FS 8<CR><LF>
size = a
write
#FS,8<CR><LF>
.write(27, a)
#FS,8 8<CR><LF
a = 3 .. 32
SF11 Laser altimeter - Product manual - Revision 9 | of | © LightWare Optoelectronics (Pty) Ltd, 2019 | www.lightware.co.za 14 20