SF30 Accelerated laser rangefinder
Product manual
9. The alarm interface
The alarm output is a 0 V to 3.3 V signal that becomes active low when the distance reading falls below a preset distance. The
distance value used to calculate the alarm state is taken from the analog port settings. However, the maximum range selection of
the analog port does not limit the operational range of the alarm.
Figure 8 :: Alarm interface connections
The “8: Alarm activation distance” setting determines the distance below which the alarm signal becomes active (low).
The “9: Alarm hysteresis” setting determines how far the distance needs to travel over the activation distance in order to change
state from activated to deactivated or deactivated to activated.
The “A: Alarm latch” selection turns on or off a latching function that keeps the alarm in an active state until a reset command is
received. The reset can be initiated from the USB port by sending an X.
10. USB port settings
The “9: USB port update rate” setting allows the user to adjust the update rate of the distance readings to make them more
readable in the Terminal window.
Setting
Values
Description
8: Alarm activation distance
0.5 m … 254 m
Sets the distance below which the alarm signal will change to a low state.
9: Alarm hysteresis
0.06 m … 50 m
The distance the reading needs to travel from the “8: Alarm activation
distance"
before the alarm is activated or deactivated.
A: Alarm latch
ON or OFF
Enables the alarm signal latch. This keeps the alarm in the active low state after
an alarm event until it is cleared by sending “X” over the USB port.
Setting
Values
Description
3: USB port output rate
39 … 625 readings / sec
Set the rate at which new results are output from the USB port when it is
selected using “1: Output type”.
The maximum value is limited to 625 readings per second, or the exposure
time - whichever is smaller.
SF20 Rangefinder - Product manual - Revision 8
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