2023-12-11 at 10:57 AM #18226
Hello, I have issues with particular rain gauge. Hopefuly someone has already encountered something like this.
The rain gauge is mechanical “tipping” one, but it does not have two containers for water / two stable states.
It has just one “spoon” which collects water and once it is full it should tip and empty itself and return to default state with empty spoon in upper position. Problem is that sometimes after tipping it does not return back and it can take hours, days, even week or more till some random thing happens and the bucket/spoon returns back to its position.
This is not nice behavior, but ok. Much worse is that this rain gauge is connected to datalogger which is designed for tipping rain gauge and thus expects just short pulses on rain gauge input. This datalogger can’t handle well permanent on state (short circuit) on its rain gauge input. It just seems to be stuck in some loop and does not do anything till the rain gauge recovers.
I am looking for ideas how to handle such unfortunate scenario.
Three solutions are on my mind:
- just throw away those cheap rain gauges and use proper ones, cause they are missing some precipitation when stuck anyway
- try to modify firmware for the logger as I am able to access source code and I don’t understand why the rain gauge input is handled so badly.
- connect some simple circuitry between logger and rain gauge. Rain gauge is connected between 3.3V voltage source and 10kOhm pull down resistor. In default state, the datalogger input is zero/low. I could use some integrator i guess.
Problem is, of course, that i dont have that much time to tinker with it.
Rain gauges were cleaned and it did not help with the issue. It is just not the most reliable design.
Thank you for help.
2023-12-12 at 10:33 PM #18233Shannon HicksModerator
Can you share the model number and manufacturer of the rain gage, or attach a picture of it that shows the tipping mechanism?
2023-12-13 at 10:15 AM #18234
It is ECRN-50 by Meter Group. There is “spoon” stuck in lower position in the picture.
2023-12-13 at 11:23 AM #18236Shannon HicksModerator
There should be little adjustment screws or stops that allow you to calibrate the sensor to tip at exactly one millimeter of rainfall (which is 5.0 ml of water). Did you try adjusting them and doing the calibration procedure before deployment? You also have to ensure that the sensor is installed completely level and that it is mounted to a firm pole or mount that doesn’t move. If any tipping bucket rain sensor is installed unlevel, it can cause accuracy issues and improper operation. We’ve also encountered spiders that make webs during dry periods that can cause them to not tip properly during rain events (I don’t think that’s your current issue, but it’s something to watch out for on long deployments.)
2023-12-14 at 1:38 PM #18240
Thank you very much for the answer. No, the rain gauge was deployed as it came out of the box. The sensor was leveled during installation, but the pole was not re-leveled since then and it was there for two or three years. I was asking Meter for help and asked them directly if there is some posibility to adjust it and they said “no” so I am bit surprised there might be calibration possible. But i doubt it would help as the spoon gets stuck in lower position where there is no “endstop”. Unfortunately I don’t have the rain gauge here and I can’t check it now. Spiders and so on are not the cause of this as rain gauges were cleaned well and the issue is still there. I was thinking if some hydrophobic treatment on the spoon surface would not help to drain the spoon properly. They told me in Meter to clean tipping point/axis with isopropyl alcohol. If you are also using ECRN-50 or similar product, you might have the same issue, just dont know about it, because your loggers behave better and you just miss some precepitation here and there without noticing.
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