Resolved AC4040 Fan

I have a similar problem with my AC4040FSI. When the weather was warmer, the fan ran but was very irregular in its speed. I now find that in -20C weather it can turn off completely and not come back on when it needs to maintain it's set point. I also have a AC4040BSI that does not vary anywhere near as much, but it runs at ambient of no less than -5C.

I have tried to set the fan speed from auto to one of the presets - low, med, or high but it seems to still fluctuate a lot. I am wondering if these presets are a maximum and the fan speed still varies with a range. The problem seems to get worse if I leave the camera on 24/7. I like to leave the camera always powered up, cooler off, in the coldest months. When I do so the fan is more stubborn to come on. Last night it refused to and would not reach it's setpoint of -30C and could only reach -25C or so with cooling at 100%, fan not running. I powered it down and today it is working in its variable way. My FPGA Revision is 15, Wifi revision is blank, DLAPI is 2.7.1.0, Windows 10 up to date.

My questions are:
1) Should I not be leaving my camera powered up in very cold weather?
2) Is it normal that the fan speed varies even when a preset is selected?

 

Up until yesterday I have always run both cameras on auto fan. The BSI camera behaves smoothly. It’s the FSI whose fan speed varies from slow to high to slow again, sometimes within 10-15 seconds. The sensor temperature is either slowly reaching its set point, or constant once there, it’s just that the 2 cameras behave differently. Perhaps there is a reason and that’s fine.

So sticking with the FSI, the night before last after having been powered up for 3 days the fan was completely off in -20C ambient. I attempted to cool my chip to -30C. The cooler came on and slowly went to 100% as the chip temperature dropped but only to about -25C. I expected the fan to kick in but it did not. I tried setting the fan to high but it did not respond. I think it was in a funky state because of the cold ambient. I gave up and powered down.
Last night, same ambient, I powered up and set the fan speed to high. Although the fan did not immediately go to high it did and ran flawlessly for at least 8 hours set at -30C. When I was done and in warm up mode I set the fan to auto and it immediately dropped down in speed so I know now a bit more of how it reacts to fan speed adjustment. I am thinking I will find a good fan speed for the conditions and set it to manual in the future, especially since you mentioned that it will override if things overheat. So I think my 2nd question has been answered.

The answer to my first question regarding whether it is better to leave my camera powered up in cold weather is still unclear to me. I get mostly temperatures from 0C to -25C with elevated humidity for several months. My thinking is it is better for the electronics to stay warm and flush the humidity than to be powered down. I believe I was connected to MAXIM with the cooler off in the above scenario. Maybe it is better to be disconnected? The above case was not the only time I had trouble getting the fan going. It happened before, when left it powered up in cold weather. The fan off when I started the session, and the fan stubborn to come on, but it always eventually did. Maybe I was not patient enough last time, but I did wait several minutes during which I was trying to turn on the fan manually. Maybe that put it in a funk? Anyway, just a recommendation to “power on or power off“ during cold weather is all that I expect until I can produce better details.

Sorry for the rambling but Colin did ask for more details

 

Camera SN: AC4040M-23110303.
The fan has behaved like this from day one, which was about 4 months ago. It sounds good, like my BSI (like a plane taking off), just varies a lot more.
Thanks for the advice about leaving it powered up, but disconnected from the software.
I will pay more attention to the fans behaviour and report anything significant.
Many thanks for your reply.

 

Last night I tried the things you mentioned. So starting with the camera powered up for 5 hours not connected to Maxim:

1) The fan, that was running when I powered it up, was off.
2) I started Maxim, set the fan speed to “high”, connected the camera, and set the cooler to -30C, no fan yet.
3) The cooler slowly went to 100%, chip temp slowly to -26C, no fan yet.
4) When the Heatsink hit 18.5C the fan came on, fluctuating a lot, and the chip stated to reach -30C.
5) The cooler % slowly dropped to 37%, when the Heatsink hit -9C the fan went off.
6) It repeated the cycle at basically the same temperatures, not maintaining -30C but going to about -26C at the peak.
7) It did this, fan on and off, in 15 minutes intervals for the duration of my 3 hour session.
8) At the end of my session, I hit the “warmup” button, and the fan came on high!!! Surprised, I waited 2 minutes, enjoying the sound.
9) I hit cooler off, fan continued on high, waited 2 more minutes, then disconnected, fan still going.
10) I then went to play with my fan speed and found that the fan immediately responded to the changes as they should.
11) I set the fan to auto, disconnected the camera, and closed Maxim. The fan was running.
12) This morning the fan was off. I started Maxim, connected the camera, but it had returned to the odd behaviour.
13) I tried hitting cooler “warm up” which had triggered the fan the night before, and “cooler off”, no fan.
14) I tried to set the fan manually, no response.
15) When I disconnected the camera the fan came on, and I was able again the set the speed manually.
16) I have reconnected the camera and am running it on medium now. Its fan speed varies a bit but not much. I will leave it running for now.

I differ to you on what to do next. You may login to my system if you wish to check things for yourself.

 

-15C to -20C
It is running now at -3C ambiant, set at -10C, 30% cooler, Heatsink 9C, fan steady on medium and I can still access the fan speed.
I will take calibration darks tonight, disconnect it, and leave it powered on. It will be warmer than last night. I will see if the fan turns off again and whether it goes back into a funk.
Let me know if there are other tests you want me to perform. It will be back down to -20C at night on Friday.

 

Last night I stared Maxim, set the fan to high, and connected the camera.
The fan did not run on high. Readings were:
Ambient -4C, set at -30C, cooler 100%, chip -26C, Heatsink 14C, fan low to medium.
I warmed up the chip….7%
2 hours later the fan was now running on high so I tried again:
Ambient -6C, set at -30C, cooler 70%, chip -30C, Heatsink 5C, fan on high.
It ran steady for 1.5 hrs taking images, and then the fan started varying - low/med/high:
Ambient -6C, set at -30C, cooler 80%, chip -30C, Heatsink 8C, fan on high varying L/M/H.
I let it go and it completed the calibration images and seems to have maintained the chip at -30C.
This morning the fan was running on high again, and I was able to access the fan speed.
I set the fan to auto, and shut down Maxim. Still powered on fan was now running on low.

To summarized, sometimes I cannot access the fan speed. I change the value but the fan does not react. It seems hitting “warm”, “off”, or disconnecting the camera jolts it into allowing me to change the speed. However, even when I can access the speed and set it to say high, it decides to vary the speed on its own. Originally I thought the very cold ambient temperatures brought on the problem, but -6C is not that cold. It seems that when it is colder and the fan goes off completely, it is slower to come back on and does not maintain its set temperature. When I received the camera in the Fall, I was always running on auto and was not paying attention to fan speed before, happy that it maintained its temperature. But as I said in the beginning of this thread, I did notice that the fan has always varied much more than my AC4040BSI.

 

From the first posting…
My FPGA Revision is 15, Wifi revision is blank, DLAPI is 2.7.1.0, Windows 10 up to date.

 

I also note that it is now powered up, cooler off, disconnected, on auto fan, -1C ambient, and the fan is varying between low and medium.

 

After servicing the problem was resolved, thx.