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 calibration run, 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 status screen is displayed. The text at the bottom 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 displayed distance freezes. This value should be 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.