On Saturday, 4 January 2020 15:54:32 GMT Graeme Gemmill wrote:
> Terry, thanks for your recent comments. I liked the reasoning about
> possible failure of the DS2490 bridge. However I swapped it over with
> its mate on the other Pi, and it appears to be working perfectly. The
> DS18B20 has been replaced but has not been recognised as a 1-wire
> device, so that needs a bit more investigation. Furthermore, there are
> signs of corrosion on the RG45 conections of those sensors that are
> outside (protected in a box with loose plastic cover, but nevertheless....)
Clearly if the DS2490 bridge isn't connecting to the Sensors properly then the
Pi wouldn't be able to 'see' the device. That has to be the first port of
call.
Just to clarify, this is the male RJ45 connector that plugs into the sensor on
the Hobby Boards PCB? I'm assuming that there is an RJ45 receptacle on the
PCB as well as on the bridge and so the cable is a simple Cat 5 drop cable?
If so, you should be able to replace that.
However, if the corrosion is on both the male half and the receptacle, then
you might find it a bit more difficult. I'm afraid the nature of the contacts
in
RJ45 connectors makes cleaning them fairly difficult.
Are the sensors on their PCBs protected from the elements inside a sealed box
and if so, is the Cat45 connector protected against the ingress of moisture
(both the liquid stuff and humidity)? If not and this is the problem, it is
likely to recur.
--
Terry Coles
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