Discrepancy between SST digital and temp graph

[southatlantic]

I have a NaveNet 3D System including 4 displays and a DFF1. The digital temperature shown in one of the user-defined data boxes is very accurate (checked against a thermometer at the same depth and position as the transducer ) - Great!
The bad news is, the graph that shows on the screen of the fish finder (very useful to find temperature breaks ) shows a temperature about 0.6 degrees C lower. :questions Is there a way to calibrate the scale of this graph without disrupting the digital readout? I assume both temps come from the same source - the transducer (an Airmar SST270W) . The same discrepancy shows in the two screens that display the fish finder

 

[Anonymous]

No, there's no way to adjust the scale of the temperature scale on the screen. You are correct that the temperature graph information is based on the same temp coming from the transducer and being displayed in the data box. The current data from the transducer is displayed on the far right side of the screen and all the information that's moving from right to left is "history". Having said that, the temp reading on the temp graph that should be compared to the data box reading is the pixel that is on the far right side of the screen. As the temp scale is displayed on the far left side of the screen, I'm not sure how accurate a reading can be determined by "line of sight". In other words by the time the graph line intersects with the temp scale, it's already many seconds behind the temp data being displayed in the data box.

 

[southatlantic]

Thank you for your reply, TheReaper. I last measured the discrepancy (6 separate measurements, all very consistent) with the boat at the dock, so the graph was very constant/horizontal.
In any case it is not a big problem, I guess I will use the graph just for trends and discontinuities that might indicate currents and get used to looking at the data box for the actual value.
Thanks again.