Hi Anthony, great to see the SensorModbusMaster detail.
FYI for the Keller Acculevel I found they had the CRC16 bytes switched around. Its well documented in the manual “Keller CRC16.
Also, if you are looking for accurate measurement at low levels of stream depth with low temperature dependency I’ve found the Keller Nanolevel to be about +/-0.05% across TEB. It uses a capactive sensor rather than the piezo resistive sensor of the acculelvel series. However it only has a range of 0-11′, and wider sensor body.
When considering the accuracy of the Acculevel, in discussion with Keller, I found their base level accuracy TEB (Total Error Band) is for +/-30′ Full Scale – so specifying a sensor with a range of less than that, the TEB is still for +/-30′. Not so much of a problem if the water temperature is constant in deeper water, but becomes relevant for measuring low water levels were there can be significant temperature shifts over a day.
The Keller devices allow for a number of types of jackets – “Polyethelene for general purpose” ie water is now recommended. The early Acculevel datasheets and Instrumart techsupport recommended Hytrel jacket and these developed fissures after only 6months in the water, and had to be replaced – a lot of field work.