5. PERFORM INITIAL TEST—LOW-GAIN MODE
Test for basic system functionality as follows:
a. Set up the physical layout of the testing environment.
i. Position the LRF to target an object within 10 meters.
ii. Ensure no highly reflective object is within 10 meters of
the LRF; such an object may damage the receiver.
b. Set the LRF to low-gain mode: Command
“:GN 0”. The command and response are
shown right.
Ensure consistent calibration and false-
alarm rate (FAR) are set for the LRF—
functionality of the LRF and flex cable within—as follows:
i. Query the low-
voltage detection threshold (vThLo):
Command “:CL”
ii. Verify the response is between 983 and
to a vThLo range
of 0.48V–0.56V;
“1025”, shown,
correlates to a
vThLo = 0.5V.
iii. Measure the
FAR: Command
“:FL”.
iv. Confirm the FAR is 100 – 500 Hz (factory default FAR).
v. Repeat steps (i) – (iv) several times.
vi. Verify the responses are consistent.
d. (Optional, if an IR card is available)
Confirm the laser is firing:
i. Place an IR card in front of
the laser.
ii. Issue a series of range
requests (command “:RR”
several times).
iii. Verify the laser pulse is
visible on the IR card.
e. Ensure the laser delay is in the
range of 1.0 – 2.2-ms at room
temperature:
i. Request the range (:RR).
ii. Request the laser delay (:RD).
iii. Read the laser delay value.
Laser delays vary by laser type;
typical is < ~2 ms. In the example
shown, the delay is 1.1 ns (“1139” in the response syntax).
f. Verify consistent/proper LRF
functioning:
i. Issue several more range
commands (:RR).
ii. Monitor the response from
the LRF.
In this configuration—because
the LRF will not resolve returns < 10 meters—the LRF respons
e
is “~RR no hits [1001] Errors”, as shown.
g. If there is a false hit—a non-zero
value (typically < 2 km) received
when zero is expected—check
the pulse width of the laser:
i. Request the pulse-width:
Command “:PW”.
In response to this request,
the pulse width of the
outgoing (T0) pulse is listed
first, followed by any return pulse widths; e.g., “
344404, 6072 OK” indicates the T0 pulse
ns and the return is 6 ns.
ii. Verify that the pulse width of the T0 pulse is hundreds of ns
and verify that any false return value is much smaller
the T0 value. A typical false return is about 10 ns (or less).
the LRF does not pass testing, contact Voxtel:
Engineering support, support@voxtel-inc.com
6. PERFORM INITIAL TEST—HIGH-GAIN MODE
Test for functionality at a distance as provided below. This process repeats several of the low-gain
command sequences in a higher-gain mode for a target at a greater distance.
a. Set up the physical layout of the testing environment:
Position the LRF to target an object at a 50 – 200-meter
range.
b. Set the LRF to high-gain mode: Command “:GN 1”.
c. Ensure consistent calibration and FAR:
i. Query vThLo: Command “:CL”.
ii. Verify the response is between 983 and 1148.
iii. Measure the FAR: Command “:FL”.
iv. Verify the FAR is 100 – 500 Hz.
v. Repeat steps (i) – (iv) several times.
vi. Verify the responses are consistent.
d. Ensure the laser delay is 1.0 – 2.2 ms at room temperature:
i. Issue a range request: Command “:RR”.
ii. Issue a laser delay request: Command “:RD”.
iii. Read the laser delay value.
e. Verify consistent/proper LRF functioning:
i. Issue several more range requests: Command “:RR”.
ii. Monitor the response.
iii. Verify that the LRF responds with non-zero values
that are consistent with the target distance.
f. If there are multiple returns/false hits, or if lighting
conditions change, reset the calibration and FAR. To reset
the calibration and FAR, repeat step (c).
g. Verify that the pulse width of
the T0 laser pulse is greater
than the pulse width of the
return(s):
i. Issue a range request:
Command “:RR”.
ii. Check the pulse width of
the returns: Command “:PW”.
The T0 pulse is reported first, followed by the return pulse(s).
A typical output for high-gain testing to a 105-meter target is
shown. Also included is an example of the return pulse widths
showing an 87.4-ns T0 pulse, a 97.5-ns return, and a typical
11.7-ns pulse-width false return.
If the LRF passes initial testing in high-gain mode:
The LRF is functioning as intended. Additional testing can be
conducted. For additional questions regarding communication
with the system board or troubleshooting, refer to the LRF
Software ICD and/or the LRF User Manual.
If the LRF does not pass testing, contact Voxtel:
Engineering support, support@voxtel-inc.com
