BigDave wrote:This is true, and should indeed be a consideration.
The sensitivity of the sensor however is quite high. I understand that it relies on some form of comparator, meaning that even a highly resistive connection between the two terminals would trigger the relay. In fact, on reflection, I think that some means to prevent rainwater from above from bridging the contacts might be necessary.
I agree with you.
BigDave wrote:On further thought though, I'm not too sure how well the contacts of this sensor type would hold up to permanent immersion in water. As far as I am aware, they're not stainless steel so will probably corrode (but I don't know that for a fact).
The sensor body can be made from water resistant plastic or polymer, see below.
BigDave wrote:These sensors are really designed to be "normally dry" as far as I am aware, but I'm sure that versions exist which are designed to be permanently (or nearly permanently) immersed.
There is sensors available to be permanently water immersed, like this:
P7280501.JPG
P7280506.JPG
This sensor was spare from a project that I´m was partner a few years ago, this sensor particularly, was installed inside a telecom cabinet, about two centimeters near the floor, then connected to the on cabinet remote alarm system, to give us an alarm in the Network Control Center in case of cabinet flooding. (We have also other alarms: fire, open doors, power systems fail, etc..)
BigDave wrote:Not sure that contamination in the water course would prevent a device which works by conductivity from working though. What particular contaminants did you have in mind which might prevent it from working?
In a natural water course there is a plenty of "contaminants" can gave problems to a contact sensor: algae, fishes, floating leaves...even stones..to pinpoint a few..
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