[TG] [TG11] Recalibration of wind instrument after iTc-5 software upgrade

[Tom - Raymarine - Moderator]

Hello Tmass60,

Quote:I have recently completed software upgrades on all components in my system (see attached files) including the iTC-5 which has speed, depth, and wind connected. I performed a calibration of the wind instrument (E22078 vane style) connected via iTC-5 which was working correctly before the software upgrade.

For future reference, re-calibration is not normally required after a software update, we try hard to avoid you having to do this. The one recent exception to this is when we went from v1 to v2 Evolution autopilot software, which changed enough of the internals of the pilot's function that the old calibration values no longer applied.

Quote:After calibration however the wind speed reading does not seem indicate wind speeds much more than 7 to 10 knots despite true wind conditions later in the day that were considerably more than this.

What wind speed value were you looking at: Apparent, True or Ground wind? If either True or Ground, what does Apparent show? Apparent is directly measured, True and Ground are calculated and therefore rely on other inputs (STW, GPS.)
The Apparent Wind Speed (AWS) values should not be affected by normal calibration (which is focussed on wind angle.) There is a wind speed offset, but you should normally leave it on the default 0.7 or 0.75 factor.
Assuming the wind speed cal factor hasn't been changed, the usual reason for under-reading AWS is physical: a poor contact in the signal line, moisture in the masthead connector or electrical interference on the analogue signal wire masking some of the speed pulses.
There's no simple test for these sorts of problems: you would need to look in detail at the signal voltages on the yellow wire coming into the ITC5, but you can't do this with a multimeter (which is only good enough for a basic proof-of-life test): you'd need an oscilloscope. On the off-chance you or a friend do have a 'scope, you'd be looking for a 0 - 8V square-wave with two pulses per rotation of the cups, between yellow and shield/bare.

Quote:Also, my vane offset after alignment calibration comes out as 172 degrees. Is it typical for this offset to be such a large amount?

This is perfectly normal. The original orientation is arbitrary and the required offset could be anywhere between 0 and 180 degrees.

Regards,
Tom