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QHY600 Problem: CCD temp rises despite cooling power ist a 100% with bias frames

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Hi QHY600 fans on linux (Ubuntu 22.04)

I start capturing reference images.
I cool the camera down to -10 degrees and it stabilized there. Cooling power is about 65%
If I take lights, temperature stays constant at -10
If I take a bias frame with 0,001s exposure time, temperature rises continuously but cooler power goes to 100%.
This behavior is observable in any SDK

Any ideas why this happens ? Currently I'm not able to gather bias frames

Michel
1 year 5 months ago #87011

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Reading out the camera does produce heat, and if you do BIAS you read out at a high rate, due to the short exposure time. You could either try to take the BIAS in a fridge, or add a delay to the image acquisition to reduce the heat production....
1 year 5 months ago #87013

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Agree reading does cause heat. But I only do a single bias frame, which causes this behavior and a single 1s light frame does not. So I would suspect another reason for this.

Michel
1 year 5 months ago #87014

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Uuh, with a single frame? Indeed, that must be something completely different and rather sounds like a firmware or hardware issue, as you write it happens with various SDKs probably the latter :(
1 year 5 months ago #87015

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I have found the temperature control to be quite wonky. Sometimes when I set it to -10 it goes there, sometimes the heater goes to 100% but it warms up. Sometimes it initially appears to cool but changes direction for no apparent reason. If I restart indi and try again I can eventually get it cooling and controlling but it can take a couple of attempts. I see this with my QHY600 but not my QHY268?
1 year 5 months ago #87048

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I got the same behavior when taking BIAS but with QHY268M.
1 year 5 months ago #87050

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I think it is due to the default behavior of the firmware to start with cooling at a low level and wait until you take a longer duration image. This is supposed to be fixed in more recent firmware but on ubuntu 22.04 the firmware update doesn't work:

Sep 10 17:23:53 plutoniborg systemd-udevd[37181]: 4-1.2:1.0: Process '/sbin/fxload -t fx3 -I /lib/firmware/qhy/QHY600.img -D ' failed with exit code 255.
Sep 10 17:23:53 plutoniborg systemd-udevd[37181]: 4-1.2:1.0: Process '/bin/sh -c 'test -f /sys/module/usbcore/parameters/usbfs_memory_mb && test $(cat /sys/modul>


The version of fxload in ubuntuclaims to support fx3 (usb3) but it doesn't work.
1 year 5 months ago #87051

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BTW temperature shouldn’t matter for bias frames
1 year 5 months ago #87060

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