iTC-5 log accuracy

[billc42]

I've installed an iTC-5 to connect my wind, speed and depth transducers into my network. This allowed me to remove five wires from my helm pod and replace them with one STng cable when I upgraded to p70, i50, i60, i70. Every time I turn off my instruments, the iTC-5 is dropping the tenths value from the log (distance). If I travel 15.6 NM, after I turn my instruments back on the log reads 15.0 NM; .6 is lost. If I travel another 20.8 NM, the next time I turn my instruments back on the log will read 35.0. The .8 is lost, now totaling 1.4 lost. If the average distance tenths value is .5, that means after 10 cycles (perhaps days, trips or legs) of the power switch I could be losing 5 miles. If power is cycled 100 times (a short season), that's 50 miles my log is missing.
The issue is with the iTC-5. The i50 Tridata, i70 and e95 all reflect this loss. The only thing impacting this is power to the iTC-5 as powering any of the other devices does not drop the tenths.
Will there ever be more updates to the iTC-5? My iTC-5 version is at v1.12 (2014).
Thank you.

[Steve - Raymarine - Moderator]

At this point, the log data is rounded when power cycled. I have forwarded your suggestion as a feature request, for a possible future software upgrade change. With log data counting when not moving in current, the log data has always been know as non-specific distance counter, to understand a general distance traveled.

[billc42]

Thanks for the reply.
Okay, for your statement regarding “non-specific distance counter”. STW from a transducer (hence Trip and Log calculations) is affected by tide, current, leeway, mounting, etc. My e95 MFD presents four Ground Trip values and Ground Log. These are from GPS SOG? Transducer derived distance can certainly measure differently than GPS measured distance. The Ground Log and Ground Trip are perhaps better for navigation.

Thanks again!

[Steve - Raymarine - Moderator]

Yes, Ground log and trip are from the GPS. It is a little more specific, but with the movement (orbit) of satellites above, you can be registering little movement with the boat sitting. But much less then all the external factors affecting a speed transducer.