Topic: Weird solar radiation values

[kobuki]

I've been observing weird values coming from my ISS where there's no solar sensor installed (it's connected to the ATK SIM). It's transmitting a value around 1600 W/m². I've never experienced this before. The weather is cold, rainy and cloudy. Could it be caused by some kind of short or rather, a measurable resistance caused by moisture mistaken for a solar sensor by the SIM board? Has anyone experienced something similar? I was able to fix it for now as I have my own receiver and driver for WeeWx, but in any case I want to get to the bottom of it. Thanks for any ideas in advance.

[galfert]

Next time it happens wipe down the sensor that is probably wet on the outside. If there is a water drop on top of the sensor it can act as a lens and magnify the light intensity and throw off the sensor.

[kobuki]

Next time it happens wipe down the sensor that is probably wet on the outside. If there is a water drop on top of the sensor it can act as a lens and magnify the light intensity and throw off the sensor.

It's happening on the station where there is NO solar sensor. It's on the ATK and data coming from there is fine. That aside I doubt a small drop of water would have any effect as the amount of irradiation doesn't change on the diffusor, but rather just transmitted to the diode unevenly.

[galfert]

Oh ....I misread what you originally wrote, as I read too fast. Oh wow...no sensor.  Hmmm...electrical short? I have no clue.

[galfert]

Have you taken it apart and visually inspected? Sometimes little critters (ants, bugs, etc.) can make nests and mess things up.

[kobuki]

Have you taken it apart and visually inspected? Sometimes little critters (ants, bugs, etc.) can make nests and mess things up.

Not yet, will sometime this week.

[kobuki]

OK... The rain stopped a few hours ago so I went and checked the SIM. To my surprise there was water in the sensor sockets and on the board. I don't really get it. I recently replaced the cover with a brand new one from Scaled Instruments. I have never seen water in the SIM shelter box, this is a first. I might have made a mistake last time when I replaced it and misaligned it or left an opening. In any case I soaked up the water in the sockets and around them using some dry cloth, applied compressed air to drive out the leftovers as much as I could and put back the cover. I triple checked the cover placement now. In any case, the weird values stopped coming from the transmitter. There was literally water in the socket, possibly causing false values of sunlight. If we're lucky we'll have some sunshine tomorrow so I can open the box again and let it dry a bit more...

[galfert]

Well only two ways in. I would clean the gasket and use some gasket lubricant. Then make sure the foam where the cables come in is also clean and and making a good seal. Lastly make sure the cover is fully seated down all the way. Maybe throw in a silica packet to reduce moisture inside the box.

[kobuki]

I think unless I screwed up putting the lid in place, there should be no way for an average rain to enter the box. It's designed so the water is nicely flowing around the edges. For about 5 years I had zero problems. I'm betting on my own fault with the previous lid (mis)placement.

[kobuki]

Today the unconnected UV sensor data is acting up in the same way. I opened the box, and found it was completely dry. I haven't removed the protective cover above the supercap and the electronics yet, I might do that a bit later, but I'm suspecting a failed board.

*sigh* time to get a spare, it seems...