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.
Tocarry out a speed calibration, start the Intermediate calibration
procedureand use the speed key to proceed to the Calibration run length
screen(see sheet 1 of the Speed calibration flow chart). Proceed with the
speedcalibration as follows:
1. Withthe Calibration Run Length screen displayed, press the trip and
reset keystogether to enter adjust mode. In this mode, the displayed
runlength flashes on and off.
2. Setthe length of the intended calibrationrun, using either the trip key
todecrement or the reset key to increment the run length value. You
canset any value between 0.25 and 2.50.
3. Presstrip and reset keys together to commence the speed calibration.
TheCal status screen is displayed.T het ext att hebottom of the screen
alternatesbetween Strt 1 and the calibration factor(CF) currently
applied.
4. Startfirst outward leg of the calibration run and as you passt he start
point,press the speed key, so that the text outshows at the bottom of
thescreen. As the calibration run proceeds, the displayed value will
increment.
5. Atthe end of the measured distance on the outward leg, press the
speedkey again so that:
• Thetext rEtrn is flashing at the bottom of the screen.
• Thedisplayed distance freezes. Note that this value will not be the
sameas the measured distance due to errors introduced by tidal
flow.
6. Turnthe vessel round, start the return leg and as you do so, press the
speedkey so the rEtrn legend stops flashing and the displayed value
increments.
7. Atthe end of the return leg, press the speed key to endthe calibration
run.At this point:
• Thetext Strt 2 alternating with the new calibration fac tor is dis-
playedat the bottom of the screen.
• Thedisplayed distance freezes. This value should be very close to
theactual (measured) distance of the calibration run.
8. Pressthe depth and speed keys together, to store the new calibration
factor.
81040_1.book Page36 Thursday, November7, 2002 10:21AM