36 ST60 Tridata Instrument Owner’s Manual
Note: It is recommended that the speed calibration procedure is carried
out in conditions of minimum tidal drift.
To carry out a speed calibration, start the Intermediate calibration
procedure and use the
speed key to proceed to the Calibration run length
screen (see sheet 1 of the Speed calibration flow chart). Proceed with the
speed calibration as follows:
1. With the Calibration Run Length screen displayed, press the
trip and
reset keys together to enter adjust mode. In this mode, the displayed
run length flashes on and off.
2. Set the length of the intended calibrationrun, using either the
trip key
to decrement or the
reset key to increment the run length value. You
can set any value between 0.25 and 2.50.
3. Press trip and reset keys together to commence the speed calibration.
The Cal statusscreen is displayed.Thetext atthebottom of the screen
alternates between Strt 1 and the calibration factor (CF) currently
applied.
4. Start first outward leg of the calibration run and as you pass the start
point, press the
speed key, so that the text out shows at the bottom of
the screen. As the calibration run proceeds, the displayed value will
increment.
5. At the end of the measured distance on the outward leg, press the
speed key again so that:
• The text rEtrn is flashing at the bottom of the screen.
• The displayed distance freezes. Note that this value will not be the
same as the measured distance due to errors introduced by tidal
flow.
6. Turn the vessel round, start the return leg and as you do so, press the
speed key so the rEtrn legend stops flashing and the displayed value
increments.
7. At the end of the return leg, press the
speed key to end the calibration
run. At this point:
• The text Strt 2 alternating with the new calibration factor is dis-
played at the bottom of the screen.
• The displayeddistance freezes. This value shouldbe very close to
the actual (measured) distance of the calibration run.
8. Press the
depth and speed keys together, to store the new calibration
factor.
81040_1.book Page 36 Thursday, November 7, 2002 10:21 AM