Compass Calibration Verification; Figure 10. Bbtalk Command History Box - RD Instruments WorkHorse User Manual

9.2

Compass Calibration Verification

Compass calibration verification is an automated built-in test that measures
how well the compass is calibrated. The procedure measures compass pa-
rameters at every 5º of rotation for a full 360º rotation. When it has col-
lected data for all required directions, the Workhorse computes and displays
the results.
NOTE. Verify the compass if you have just replaced the memory module,
or any ferrous metals is relocated inside or around the Workhorse housing.
Calibrate the compass if the batteries have been replaced (see "Compass
Calibration Procedure," page 20).
a. Prepare the ADCP for calibration (see
18).
b. Using BBTalk, send a Break to wake up the Workhorse.
c. On the Transfer menu, click Command History. In the Enter a
Command box, enter AX and click OK.
Figure 10.
d. When prompted, rotate the Workhorse slowly 360 degrees (approxi-
mately 5 degrees per second). Pay particular attention to the Overall Er-
ror. For example;
HEADING ERROR ESTIMATE FOR THE CURRENT COMPASS CALIBRATION:
OVERALL ERROR:
Peak Double + Single Cycle Error (should be < 5():
DETAILED ERROR SUMMARY:
Single Cycle Error:
Double Cycle Error:
Largest Double plus Single Cycle Error:
RMS of 3rd Order and Higher + Random Error:
If the overall error is less than 2°, the compass does not require alignment.
You can align the compass to reduce the overall error even more (if de-
sired).
P/N 957-6169-00 (April 2005)
BBTalk Command History Box
WorkHorse Mariner ADCP User's Guide
"Preparing for Calibration," page
( 1.55(
( 1.54(
( 0.07(
( 1.61(
( 0.31(
page 19